View source for Biology:Human

{{Short description|Species of hominid in the genus Homo}}
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{{Speciesbox
| name = Human<ref name=msw3>{{MSW3 Groves |pages= |id=12100795 |name-list-style=vanc }}</ref>
| fossil_range = {{Fossil range|0.300|0}} <small>[[Earth:Chibanian|Chibanian]] – [[Earth:Holocene|present]]</small>
| image = Akha cropped hires.JPG <!--The choice of image has been discussed at length. Please don't change it without first obtaining consensus. Also used at Akha people (section Dress)-->
| image_caption = [[Biology:Adult|Adult]] humans, Thailand, 2007
<!--T| status = LC
| status_system = IUCN3.1-->| taxon = Homo sapiens
| authority = [[Biography:Carl Linnaeus|Linnaeus]], 1758
| subdivision_ranks = Subspecies
| range_map = World human population density map.png
| range_map_caption = ''Homo sapiens'' population density (2005)
| synonyms = 
}}

'''Humans''' ('''''Homo sapiens''''') or '''modern humans'''  are the most common and widespread [[Biology:Species|species]] of [[Biology:Primate|primate]], and the last surviving species of the genus ''[[Biology:Homo|Homo]]''. A [[Biology:Hominidae|great ape]] characterized by their [[Biology:Prehistory of nakedness and clothing#Evolution of hairlessness|hairlessness]], bipedalism, and high [[Philosophy:Human intelligence|intelligence]], humans have large [[Biology:Human brain|brains]], enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex [[Engineering:Tool|tools]], and form complex social structures and [[Social:Civilization|civilization]]s. Humans are [[Biology:Sociality|highly social]], with individual humans tending to belong to a [[Biology:Level of analysis|multi-layered]] network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and [[Earth:State (polity)|political states]]. As such, social interactions between humans have established a wide variety of values, social norms, [[Social:Language|language]]s, and traditions (collectively termed institutions), each of which bolsters human [[Organization:Society|society]]. Humans are also highly curious: the desire to understand and influence [[Philosophy:Phenomenon|phenomena]] has motivated humanity's development of [[Science|science]], [[Engineering:Technology|technology]], [[Philosophy:Philosophy|philosophy]], mythology, [[Religion:Religion|religion]], and other frameworks of [[Philosophy:Knowledge|knowledge]]; humans also study themselves through such domains as [[Social:Anthropology|anthropology]], [[Social:Social science|social science]], [[History:History|history]], [[Social:Psychology|psychology]], and [[Medicine:Medicine|medicine]]. As of January 2024, there are more than 8 billion humans alive.

Although some scientists equate the term "humans" with all members of the genus ''[[Biology:Homo|Homo]]'', in common usage it generally refers to ''Homo sapiens'', the only extant member. Extinct members of the genus ''Homo'' are known as [[Biology:Archaic humans|archaic humans]], and the term "modern human" is used to distinguish ''Homo sapiens'' from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from ''[[Biology:Homo heidelbergensis|Homo heidelbergensis]]'' or a similar species. Migrating [[Biology:Recent African origin of modern humans|out of Africa]], they gradually replaced and [[Biology:Hybrid|interbred]] with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species [[Biology:Neanderthal extinction|such as Neanderthals]] include competition, violence, or interbreeding with ''Homo sapiens'', or inability to adapt to climate change. 

For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting [[Philosophy:Behavioral modernity|behavioral modernity]] about 160,000–60,000 years ago. The [[History:Neolithic Revolution|Neolithic Revolution]], which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of [[Earth:Agriculture|agriculture]] and permanent human settlement; in turn, this led to the [[Social:Cradle of civilization|development of civilization]] and kickstarted a period of continuous (and ongoing) population growth and rapid [[Engineering:Technological change|technological change]]. Since then, a number of civilizations have risen and fallen, while a number of [[Social:Sociocultural evolution|sociocultural]] and [[History:History of technology|technological]] developments have resulted in significant changes to the human lifestyle.

[[Biology:Gene|Gene]]s and the environment influence human biological variation in visible characteristics, [[Biology:Physiology|physiology]], disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are [[Philosophy:Sex differences in humans|sexually dimorphic]]: generally, [[Biology:Man|males]] have greater body strength and females have a higher body fat percentage. At puberty, humans develop secondary sex characteristics. Females are capable of [[Medicine:Pregnancy|pregnancy]], usually between puberty, at around 12 years old, and [[Medicine:Menopause|menopause]], around the age of 50.

Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have [[Biology:Control of fire by early humans|used fire]] and other forms of heat to prepare and cook food since the time of ''[[Biology:Homo erectus|Homo erectus]]''. Humans can survive for up to eight weeks without food and several days without [[Chemistry:Water|water]]. Humans are generally [[Biology:Diurnality|diurnal]], [[Biology:Sleep|sleeping]] on average seven to nine hours per day. [[Medicine:Childbirth|Childbirth]] is dangerous, with a high risk of complications and [[Biology:Death|death]]. Often, both the mother and the father provide care for their children, who are helpless at birth.

Humans have a large, highly developed, and complex [[Biology:Prefrontal cortex|prefrontal cortex]], the region of the [[Biology:Brain|brain]] associated with higher cognition. Humans are highly [[Philosophy:Intelligence|intelligent]] and capable of [[Biology:Episodic memory#In animals|episodic memory]]; they have flexible facial expressions, [[Philosophy:Self-awareness|self-awareness]], and a [[Philosophy:Theory of mind|theory of mind]]. The human mind is capable of [[Philosophy:Introspection|introspection]], private [[Philosophy:Thought|thought]], [[Imagination|imagination]], [[Philosophy:Volition (psychology)|volition]], and forming views on [[Philosophy:Existence|existence]]. This has allowed [[History:History of technology|great technological advancements]] and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through [[Social:Language|language]].

Humans' advanced technology has enabled them to spread to all the continents of the globe as well as to [[Astronomy:Outer space|outer space]], and to command profound influence on the biosphere and environment. The latter has prompted some geologists to demarcate the time from the emergence of human civilization till present as a separate geological epoch: the Anthropocene (with ''anthropo-'' deriving from the [[Social:Ancient Greek|Ancient Greek]] word for "human", ''ἄνθρωπος).''

== Etymology and definition ==
[[File:Carl von Linné, 1707-1778, botanist, professor (Alexander Roslin) - Nationalmuseum - 15723.tif|thumb|upright|Carl Linnaeus coined the name ''Homo sapiens'' and is the type specimen of the species]]
All modern humans are classified into the [[Biology:Species|species]] ''Homo sapiens'', coined by [[Biography:Carl Linnaeus|Carl Linnaeus]] in his 1735 work ''[[Biology:Systema Naturae|Systema Naturae]]''.<ref>{{cite journal| vauthors = Spamer EE |date=29 January 1999|title=Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758|journal=Proceedings of the Academy of Natural Sciences |volume=149 |issue=1 |pages=109–114 |jstor=4065043}}</ref> The generic name "''[[Biology:Homo|Homo]]''" is a learned 18th-century derivation from Latin {{lang|la|homō}}, which refers to humans of either sex.<ref>{{cite book|author=Porkorny|year=1959|title=IEW|at=s.v. "g'hðem" pp. 414–116}}</ref><ref>{{cite encyclopedia |title=Homo |dictionary=Dictionary.com Unabridged (v 1.1) |publisher=Random House |url=https://dictionary.reference.com/browse/Homo |date=23 September 2008 |archive-url=https://web.archive.org/web/20080927011551/https://dictionary.reference.com/browse/homo |archive-date=27 September 2008 |url-status=live}}</ref> The word ''human'' can refer to all members of the ''Homo'' genus,<ref name="auto">{{cite web |title=We don't know which species should be classed as 'human' |url=https://www.bbc.com/earth/story/20160111-what-is-it-that-makes-you-a-human-and-not-something-else |url-status= |archive-url=https://web.archive.org/web/20210826223800/http://www.bbc.com/earth/story/20160111-what-is-it-that-makes-you-a-human-and-not-something-else |archive-date=26 August 2021 |access-date=31 March 2021 |website=BBC |language=en |first=Colin|last=Barras|date=11 January 2016}}</ref> although in common usage it generally just refers to ''Homo sapiens,'' the only [[Biology:Neontology|extant]] species.<ref>{{cite web|title=Definition of human|url=https://www.merriam-webster.com/dictionary/human|access-date=31 March 2021|website=Merriam-Webster|language=en|archive-date=11 February 2021|archive-url=https://web.archive.org/web/20210211000740/https://www.merriam-webster.com/dictionary/human|url-status=live}}</ref> The name "''Homo'' ''sapiens''" means 'wise man' or 'knowledgeable man'.<ref>{{Cite journal|vauthors=Spamer EE|date=1999|title=Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758|url=https://www.jstor.org/stable/4065043|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|volume=149|pages=109–114|issn=0097-3157|jstor=4065043|access-date=30 July 2022|archive-date=8 April 2022|archive-url=https://web.archive.org/web/20220408045630/https://www.jstor.org/stable/4065043|url-status=live}}</ref> There is disagreement if certain extinct members of the genus, namely [[Biology:Neanderthal|Neanderthal]]s, should be included as a separate species of humans or as a [[Biology:Subspecies|subspecies]] of ''H. sapiens''.<ref name="auto" />

''Human'' is a [[Social:Loanword|loanword]] of [[Social:Middle English|Middle English]] from [[Social:Old French|Old French]] {{lang|fro|humain}}, ultimately from [[Social:Latin|Latin]] {{lang|la|hūmānus}}, the adjectival form of {{lang|la|homō}} ('man' – in the sense of humankind).<ref>{{cite book|title=OED|at=s.v. "human"}}</ref> The native English term ''man'' can refer to the species generally (a synonym for ''humanity'') as well as to human males. It may also refer to individuals of either sex.<ref>{{cite web |url=https://www.merriam-webster.com/dictionary/man |title=Man |quote=Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination |work=Merriam-Webster Dictionary |archive-date=22 September 2017 |archive-url=https://web.archive.org/web/20170922050822/https://www.merriam-webster.com/dictionary/man |url-status=live |access-date=14 September 2017}}</ref>

Despite the fact that the word ''animal'' is colloquially used as an [[Opposite (semantics)|antonym]] for ''human'',<ref>{{Cite web |title=Thesaurus results for human |url=https://www.merriam-webster.com/thesaurus/human |access-date=21 May 2022 |website=Merriam-Webster Dictionary |language=en |archive-date=28 June 2022 |archive-url=https://web.archive.org/web/20220628010110/https://www.merriam-webster.com/thesaurus/human |url-status=live}}</ref> and contrary to a common biological misconception, humans are animals.<ref>{{Cite web |date=19 September 2021 |title=Misconceptions about evolution – Understanding Evolution |url=https://evolution.berkeley.edu/teach-evolution/misconceptions-about-evolution/ |access-date=21 May 2022 |language=en-US |archive-date=6 June 2022 |archive-url=https://web.archive.org/web/20220606191558/https://evolution.berkeley.edu/teach-evolution/misconceptions-about-evolution/ |url-status=live|website=University of California, Berkeley }}</ref> The word ''[[Philosophy:Person|person]]'' is often used interchangeably with ''human'', but philosophical debate exists as to whether [[Philosophy:Personhood|personhood]] applies to all humans or all sentient beings, and further if one can lose personhood (such as by going into a [[Medicine:Persistent vegetative state|persistent vegetative state]]).<ref>{{Cite web|title=Concept of Personhood |url=https://medicine.missouri.edu/centers-institutes-labs/health-ethics/faq/personhood |access-date=4 July 2021 |website=University of Missouri School of Medicine |archive-date=4 March 2021 |archive-url=https://web.archive.org/web/20210304011726/https://medicine.missouri.edu/centers-institutes-labs/health-ethics/faq/personhood |url-status=live}}</ref>

== Evolution ==
{{Main|Biology:Human evolution}}
Humans are apes ([[Biology:Hominoidea|superfamily Hominoidea]]).<ref>{{Cite book|vauthors=Tuttle RH |title=International Encyclopedia of Biological Anthropology |date=4 October 2018 |publisher=John Wiley & Sons, Inc. |isbn=978-1-118-58442-2 |veditors=Trevathan W, Cartmill M, Dufour D, Larsen C |place=Hoboken, New Jersey, {{wipe|United States}}|pages=1–2|language=en|chapter=Hominoidea: conceptual history|doi=10.1002/9781118584538.ieba0246|s2cid=240125199|access-date=26 May 2021|chapter-url=https://doi.wiley.com/10.1002/9781118584538.ieba0246}}</ref> The [[Biology:Lineage (evolution)|lineage]] of apes that eventually gave rise to humans first split from [[Biology:Gibbon|gibbon]]s (family Hylobatidae) and [[Biology:Orangutan|orangutan]]s (genus ''Pongo''), then [[Biology:Gorilla|gorilla]]s (genus ''Gorilla''), and finally, [[Biology:Chimpanzee|chimpanzee]]s and [[Biology:Bonobo|bonobo]]s (genus ''[[Biology:Pan (genus)|Pan]]''). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch.<ref>{{cite journal |vauthors=Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, Benson P, Slightom JL |display-authors=6 |title=Primate evolution at the DNA level and a classification of hominoids |journal=Journal of Molecular Evolution |volume=30 |issue=3 |pages=260–266 |date=March 1990 |pmid=2109087 |doi=10.1007/BF02099995 |s2cid=2112935 |bibcode=1990JMolE..30..260G}}</ref><ref name="Ruvolo1997">{{cite journal|vauthors=Ruvolo M |date=March 1997 |title=Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets |journal=[[Biology:Molecular Biology and Evolution|Molecular Biology and Evolution]] |volume=14 |issue=3 |pages=248–265|doi=10.1093/oxfordjournals.molbev.a025761|pmid=9066793|doi-access=free}}</ref> During this split, [[Biology:Chromosome 2|chromosome 2]] was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes.<ref name="fusion">{{cite web|title=Human Chromosome 2 is a fusion of two ancestral chromosomes |url=https://www.evolutionpages.com/chromosome_2.htm |archive-url=https://web.archive.org/web/20110809040210/https://www.evolutionpages.com/chromosome_2.htm |archive-date=9 August 2011 |access-date=18 May 2006 |work=Evolution pages |vauthors=MacAndrew A}}</ref> Following their split with chimpanzees and bonobos, the [[Biology:Hominini|hominins]] diversified into many species and at least two distinct genera. All but one of these lineages{{snd}}representing the genus ''[[Biology:Homo|Homo]]'' and its sole extant species ''Homo sapiens''{{snd}}are now extinct.<ref>{{Cite web |last=McNulty |first=Kieran P. |year=2016 |title=Hominin Taxonomy and Phylogeny: What's In A Name? |url=https://www.nature.com/scitable/knowledge/library/hominin-taxonomy-and-phylogeny-what-s-in-142102877/ |access-date=11 June 2022 |website=Nature Education Knowledge |language=en |archive-date=10 January 2016 |archive-url=https://web.archive.org/web/20160110013134/https://www.nature.com/scitable/knowledge/library/hominin-taxonomy-and-phylogeny-what-s-in-142102877/ |url-status=live}}</ref>

[[File:Lucy Skeleton.jpg|thumb|left|upright|Reconstruction of [[Biology:Lucy (Australopithecus)|Lucy]]'','' the first ''Australopithecus afarensis'' skeleton found]]
The genus ''Homo'' evolved from ''[[Biology:Australopithecus|Australopithecus]]''.<ref>{{cite journal |vauthors=Strait DS |title=The Evolutionary History of the Australopiths |journal=Evolution: Education and Outreach |date=September 2010 |volume=3 |issue=3 |pages=341–352 |doi=10.1007/s12052-010-0249-6 |s2cid=31979188 |url=https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-010-0249-6 |language=en |issn=1936-6434 |access-date=30 July 2022 |archive-date=31 May 2022 |archive-url=https://web.archive.org/web/20220531204050/https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-010-0249-6 |url-status=live |doi-access=free }}</ref><ref>{{cite journal |vauthors=Dunsworth HM |title=Origin of the Genus Homo |journal=Evolution: Education and Outreach |date=September 2010 |volume=3 |issue=3 |pages=353–366 |doi=10.1007/s12052-010-0247-8 |s2cid=43116946 |url=https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-010-0247-8 |language=en |issn=1936-6434 |access-date=30 July 2022 |archive-date=23 May 2022 |archive-url=https://web.archive.org/web/20220523050858/https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-010-0247-8 |url-status=live |doi-access=free }}</ref> Though fossils from the transition are scarce, the earliest members of ''Homo'' share several key traits with ''Australopithecus''.<ref>{{cite journal |vauthors=Kimbel WH, Villmoare B |title=From Australopithecus to Homo: the transition that wasn't |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume =371 |issue=1698 |page=20150248 |date=July 2016 |pmid=27298460 |pmc=4920303 |doi=10.1098/rstb.2015.0248 |s2cid=20267830}}</ref><ref name=Villmoare2015>{{cite journal |vauthors=Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, Braun DR, Arrowsmith JR, Reed KE |display-authors=6 |title=Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia |journal=Science |volume=347 |issue=6228 |pages=1352–1355 |date=March 2015 |pmid=25739410 |doi=10.1126/science.aaa1343 |doi-access=free |bibcode=2015Sci...347.1352V}}</ref> The earliest record of ''Homo'' is the 2.8 million-year-old specimen [[Biology:LD 350-1|LD 350-1]] from Ethiopia, and the earliest named species are ''[[Biology:Homo habilis|Homo habilis]]'' and ''[[Biology:Homo rudolfensis|Homo rudolfensis]]'' which evolved by 2.3 million years ago.<ref name=Villmoare2015 /> ''[[Biology:Homo erectus|H. erectus]]'' (the African variant is sometimes called ''H. ergaster'') evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia.<ref>{{cite journal |vauthors=Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, Rao Z, Hou Y, Xie J, Han J, Ouyang T |display-authors=6 |title=Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago |journal=Nature |volume=559 |issue=7715 |pages=608–612 |date=July 2018 |pmid=29995848 | doi=10.1038/s41586-018-0299-4 |bibcode=2018Natur.559..608Z |s2cid =49670311}}</ref> ''H. erectus'' also was the first to evolve a characteristically human [[Biology:Body plan|body plan]]. ''Homo sapiens'' emerged in Africa around 300,000 years ago from a species commonly designated as either ''[[Biology:Homo heidelbergensis|H. heidelbergensis]]'' or ''[[Biology:Homo rhodesiensis|H. rhodesiensis]]'', the descendants of ''H. erectus'' that remained in Africa.<ref>{{cite journal | vauthors=Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, Bergmann I, Le Cabec A, Benazzi S, Harvati K, Gunz P |display-authors=6 |title=New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens |journal=Nature |volume=546 |issue=7657 |pages=289–292 |date=June 2017 |pmid=28593953 |doi=10.1038/nature22336 |bibcode=2017Natur.546..289H |s2cid=256771372 |url=https://kar.kent.ac.uk/62267/1/Submission_288356_1_art_file_2637492_j96j1b.pdf |access-date=30 July 2022 |archive-date=8 January 2020 |archive-url=https://web.archive.org/web/20200108234003/https://kar.kent.ac.uk/62267/1/Submission_288356_1_art_file_2637492_j96j1b.pdf |url-status=live}}</ref> ''H. sapiens'' migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans.<ref>{{cite journal |author=<!--Staff writer(s); no by-line.--> |date=13 May 2005 |title=Out of Africa Revisited |journal=Science |type=This Week in ''Science'' |volume=308 |issue=5724 |page=921 |doi=10.1126/science.308.5724.921g |issn=0036-8075 |s2cid=220100436}}</ref><ref>{{cite journal |vauthors=Stringer C |title=Human evolution: Out of Ethiopia |journal=Nature |volume=423 |issue=6941 |pages=692–693, 695 |date=June 2003 |pmid=12802315 |doi=10.1038/423692a |s2cid=26693109 |bibcode=2003Natur.423..692S}}</ref><ref>{{cite web |vauthors=Johanson D |author-link=Donald Johanson |date=May 2001 |title=Origins of Modern Humans: Multiregional or Out of Africa? |url=https://www.actionbioscience.org/evolution/johanson.html |access-date=23 November 2009 |website=[[Biology:Actionbioscience|actionbioscience]] |publisher=[[Organization:American Institute of Biological Sciences|American Institute of Biological Sciences]] |location=Washington, DC |archive-date=17 June 2021 |archive-url=https://web.archive.org/web/20210617010349/http://www.actionbioscience.org/evolution/johanson.html |url-status=dead}}</ref> Humans began exhibiting [[Philosophy:Behavioral modernity|behavioral modernity]] about 160,000–70,000 years ago,<ref name="Marean et al 2007">{{cite journal |last1=Marean |first1=Curtis |display-authors=0 |date=2007 |title=Early human use of marine resources and pigment in South Africa during the Middle Pleistocene |journal=Nature |volume=449 |issue=7164 |pages=905–908 |bibcode=2007Natur.449..905M |doi=10.1038/nature06204 |pmid=17943129 |s2cid=4387442|url=http://doc.rero.ch/record/15550/files/PAL_E2962.pdf }}</ref> and possibly earlier.<ref name="Brooks">{{Cite journal |vauthors=Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB |year=2018 |title=Long-distance stone transport and pigment use in the earliest Middle Stone Age |journal=Science |volume=360 |issue=6384 |pages=90–94 |bibcode=2018Sci...360...90B |doi=10.1126/science.aao2646 |pmid=29545508 |doi-access=free}}</ref>

The [[Biology:Recent African origin of modern humans|"out of Africa" migration]] took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ([[Earth:Southern Dispersal|Southern Dispersal]]) around 70,000 to 50,000 years ago.<ref name="Posth">{{cite journal |vauthors=Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, Valentin F, Thevenet C, Furtwängler A, Wißing C, Francken M, Malina M, Bolus M, Lari M, Gigli E, Capecchi G, Crevecoeur I, Beauval C, Flas D, Germonpré M, van der Plicht J, Cottiaux R, Gély B, Ronchitelli A, Wehrberger K, Grigorescu D, Svoboda J, Semal P, Caramelli D, Bocherens H, Harvati K, Conard NJ, Haak W, Powell A, Krause J |display-authors=6 |title=Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe |journal=[[Biology:Current Biology|Current Biology]] |volume=26 |issue=6 |pages=827–833 |date=March 2016 |pmid=26853362 |doi=10.1016/j.cub.2016.01.037 |hdl-access=free |s2cid=140098861 |hdl=2440/114930}}</ref><ref>{{cite journal |vauthors=Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, Rootsi S, Ilumäe AM, Mägi R, Mitt M, Pagani L, Puurand T, Faltyskova Z, Clemente F, Cardona A, Metspalu E, Sahakyan H, Yunusbayev B, Hudjashov G, DeGiorgio M, Loogväli EL, Eichstaedt C, Eelmets M, Chaubey G, Tambets K, Litvinov S, Mormina M, Xue Y, Ayub Q, Zoraqi G, Korneliussen TS, Akhatova F, Lachance J, Tishkoff S, Momynaliev K, Ricaut FX, Kusuma P, Razafindrazaka H, Pierron D, Cox MP, Sultana GN, Willerslev R, Muller C, Westaway M, Lambert D, Skaro V, Kovačevic L, Turdikulova S, Dalimova D, Khusainova R, Trofimova N, Akhmetova V, Khidiyatova I, Lichman DV, Isakova J, Pocheshkhova E, Sabitov Z, Barashkov NA, Nymadawa P, Mihailov E, Seng JW, Evseeva I, Migliano AB, Abdullah S, Andriadze G, Primorac D, Atramentova L, Utevska O, Yepiskoposyan L, Marjanovic D, Kushniarevich A, Behar DM, Gilissen C, Vissers L, Veltman JA, Balanovska E, Derenko M, Malyarchuk B, Metspalu A, Fedorova S, Eriksson A, Manica A, Mendez FL, Karafet TM, Veeramah KR, Bradman N, Hammer MF, Osipova LP, Balanovsky O, Khusnutdinova EK, Johnsen K, Remm M, Thomas MG, Tyler-Smith C, Underhill PA, Willerslev E, Nielsen R, Metspalu M, Villems R, Kivisild T |display-authors=6 |title=A recent bottleneck of Y chromosome diversity coincides with a global change in culture |journal=Genome Research |volume=25 |issue=4 |pages=459–466 |date=April 2015 |pmid=25770088 |pmc=4381518 |doi=10.1101/gr.186684.114}}</ref> ''H. sapiens'' proceeded to colonize all the continents and larger islands, arriving in [[Earth:Eurasia|Eurasia]] 125,000 years ago,<ref>{{cite journal |vauthors=Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP |title=The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia |journal=Science |volume=331 |issue=6016 |pages=453–456 |date=January 2011 |pmid=21273486 |doi=10.1126/science.1199113 |url=https://www.sciencenews.org/view/generic/id/69197/title/Hints_of_earlier_human_exit_from_Africa |url-status=live |access-date=1 May 2011 |bibcode=2011Sci...331..453A |s2cid=20296624 |archive-url=https://web.archive.org/web/20110427201317/https://www.sciencenews.org/view/generic/id/69197/title/Hints_of_earlier_human_exit_from_Africa |archive-date=27 April 2011}}</ref><ref>{{cite web |vauthors=Rincon P |url=https://www.bbc.co.uk/news/science-environment-12300228 |title=Humans 'left Africa much earlier' |archive-url=https://web.archive.org/web/20120809051349/https://www.bbc.co.uk/news/science-environment-12300228 |archive-date=9 August 2012 |work=BBC News |date=27 January 2011}}</ref> Australia around 65,000 years ago,<ref>{{cite journal |vauthors=Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, Roberts RG, Hayes E, Lowe K, Carah X, Florin SA, McNeil J, Cox D, Arnold LJ, Hua Q, Huntley J, Brand HE, Manne T, Fairbairn A, Shulmeister J, Lyle L, Salinas M, Page M, Connell K, Park G, Norman K, Murphy T, Pardoe C |display-authors=6 | title=Human occupation of northern Australia by 65,000 years ago |journal=Nature |volume=547 |issue=7663 |pages=306–310 |date=July 2017 |pmid=28726833 |doi=10.1038/nature22968 |bibcode=2017Natur.547..306C |s2cid=205257212 |hdl=2440/107043|hdl-access=free }}</ref> the Americas around 15,000 years ago, and remote islands such as [[Earth:Hawaiian Islands|Hawaii]], Easter Island, {{wipe|Madagascar}}, and [[Earth:New Zealand|New Zealand]] in the years 300 to 1280 CE.<ref name="Lowe">{{cite web|vauthors=Lowe DJ |year=2008 |title=Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update |url=https://researchcommons.waikato.ac.nz/bitstream/10289/2690/1/Lowe%202008%20Polynesian%20settlement%20guidebook.pdf |url-status=live |archive-url=https://web.archive.org/web/20100522032853/https://researchcommons.waikato.ac.nz/bitstream/10289/2690/1/Lowe%202008%20Polynesian%20settlement%20guidebook.pdf |archive-date=22 May 2010 |access-date=29 April 2010 |publisher=[[Organization:University of Waikato|University of Waikato]]}}</ref><ref>{{cite journal |vauthors=Appenzeller T |title=Human migrations: Eastern odyssey |journal=Nature |volume=485 |issue=7396 |pages=24–26 |date=May 2012 |pmid=22552074 |doi=10.1038/485024a |bibcode=2012Natur.485...24A |doi-access=free}}</ref>

Human evolution was not a simple linear or branched progression but involved [[Biology:Interbreeding between archaic and modern humans|interbreeding between related species]].<ref name="pmid21179161" /><ref>{{cite journal |url=https://www.grochbiology.org/EarlyHominidInterbreeding.pdf |title=Human Hybrids |archive-url=https://web.archive.org/web/20180824034550/https://www.grochbiology.org/EarlyHominidInterbreeding.pdf |archive-date=24 August 2018 |vauthors=Hammer MF |journal=Scientific American |date=May 2013 |volume=308 |issue=5 |pages=66–71 |doi=10.1038/scientificamerican0513-66 |pmid=23627222 |bibcode=2013SciAm.308e..66H}}</ref><ref>{{cite journal |vauthors=Yong E |date=July 2011 |title=Mosaic humans, the hybrid species |journal=New Scientist |volume=211 |issue=2823 |pages=34–38 |bibcode=2011NewSc.211...34Y |doi=10.1016/S0262-4079(11)61839-3|doi-access=free }}</ref> Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution.<ref name="Ackermann 2015">{{cite journal |vauthors=Ackermann RR, Mackay A, Arnold ML |date=October 2015 |title=The Hybrid Origin of "Modern" Humans |journal=Evolutionary Biology |volume=43 |issue=1 |pages=1–11 |doi=10.1007/s11692-015-9348-1 |s2cid=14329491}}</ref> [[Biology:DNA|DNA]] evidence suggests that several genes of [[Biology:Neanderthal|Neanderthal]] origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as [[History:Denisovan|Denisovan]]s, may have contributed up to 6% of their [[Biology:Genome|genome]] to present-day non sub-Saharan-African humans.<ref name="pmid21179161">{{cite journal |vauthors=Reich D, Green RE, Kircher M, Krause J, Patterson N, Durand EY, Viola B, Briggs AW, Stenzel U, Johnson PL, Maricic T, Good JM, Marques-Bonet T, Alkan C, Fu Q, Mallick S, Li H, Meyer M, Eichler EE, Stoneking M, Richards M, Talamo S, Shunkov MV, Derevianko AP, Hublin JJ, Kelso J, Slatkin M, Pääbo S |display-authors=6 |title=Genetic history of an archaic hominin group from Denisova Cave in Siberia |journal=Nature |volume=468 |issue=7327 |pages=1053–1060 |date=December 2010 |pmid=21179161 |pmc=4306417 |doi=10.1038/nature09710 |bibcode=2010Natur.468.1053R |hdl=10230/25596 |author-link1=David Reich (geneticist) }}</ref><ref name="pmid20439435">{{cite journal |vauthors=Noonan JP |title=Neanderthal genomics and the evolution of modern humans |journal=Genome Research |volume=20 |issue=5 |pages=547–553 |date=May 2010 |pmid=20439435 |pmc=2860157 |doi=10.1101/gr.076000.108}}</ref><ref name="10.1126/science.1209202">{{cite journal |vauthors=Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, Babrzadeh F, Gharizadeh B, Luo M, Plummer FA, Kimani J, Carrington M, Middleton D, Rajalingam R, Beksac M, Marsh SG, Maiers M, Guethlein LA, Tavoularis S, Little AM, Green RE, Norman PJ, Parham P |display-authors=6 |title=The shaping of modern human immune systems by multiregional admixture with archaic humans |journal=Science |volume=334 |issue=6052 |pages=89–94 |date=October 2011 |pmid=21868630 |pmc=3677943 |doi=10.1126/science.1209202 |bibcode=2011Sci...334...89A}}</ref>

Human evolution is characterized by a number of [[Biology:Morphology|morphological]], developmental, physiological, and behavioral changes that have taken place since the split between the [[Biology:Chimpanzee–human last common ancestor|last common ancestor of humans and chimpanzees]]. The most significant of these adaptations are [[Biology:Prehistory of nakedness and clothing#Evolution of hairlessness|hairlessness]],<ref>{{cite journal |last1=Sandel |first1=Aaron A. |title=Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness |journal=American Journal of Physical Anthropology |date=30 July 2013 |volume=152 |issue=1 |pages=145–150 |doi=10.1002/ajpa.22333 |pmid=23900811 |hdl=2027.42/99654 |url=https://onlinelibrary.wiley.com/doi/10.1002/ajpa.22333 |access-date=22 July 2023|hdl-access=free }}</ref> obligate bipedalism, increased brain size and decreased [[Biology:Sexual dimorphism|sexual dimorphism]] ([[Biology:Neoteny|neoteny]]). The relationship between all these changes is the subject of ongoing debate.<ref name="Boyd2003">{{cite book |vauthors=Boyd R, Silk JB |url=https://archive.org/details/howhumansevolved03edboyd |title=How Humans Evolved |publisher=Norton |year=2003 |isbn=978-0-393-97854-4 |location=New York |url-access=registration}}</ref>
{{clade|{{clade
       |1=Hylobatidae ([[Biology:Gibbon|gibbon]]s)
       |label2=Hominidae (hominids, great apes)
       |2={{clade|label1=[[Biology:Ponginae|Ponginae]] |1={{clade
         |label1=Pongo ([[Biology:Orangutan|orangutan]]s)
           |1={{clade
           |1=''Pongo abelii''
           |label2=
           |2={{clade
             |1=''Pongo tapanuliensis''
             |2=''Pongo pygmaeus''
             }}
           }} }}
         |label2=[[Biology:Homininae|Homininae]] (hominines)
          |2={{clade|label1=[[Biology:Gorillini|Gorillini]]  |1={{clade
             |label1=Gorilla ([[Biology:Gorilla|gorilla]]s)
             |1={{clade
               |1=''Gorilla gorilla''
               |2=''[[Biology:Gorilla beringei|Gorilla beringei]]''
             }} }}
             |label2=[[Biology:Hominini|Hominini]] (hominins)
             |2={{clade
                |label1=[[Biology:Panina|Panina]]
                |1={{clade|label1=Pan ([[Biology:Chimpanzee|chimpanzee]]s)|1={{clade
                   |1=''Pan troglodytes''
                   |2=''Pan paniscus''
                }} }}
                |2={{clade|label1=[[Biology:Hominina|Hominina]] (homininans)|1='''''Homo sapiens''''' (humans)}}
             }}
         }}
      }}
   }}|style1=font-size:80%; line-height:80%|label1=[[Biology:Hominoidea|Hominoidea]] (hominoids, [[Biology:Ape|ape]]s)}}

== History ==
{{Main|History:Human history||}}
===Prehistory===
{{Main|History:Prehistory}}
[[File:Early migrations mercator.svg|thumb|350px|Overview map of the peopling of the world by [[Biology:Early human migrations|early human migration]] during the Upper Paleolithic, following to the Southern Dispersal paradigm]]
Until about 12,000 years ago, all humans lived as [[Biology:Hunter-gatherer|hunter-gatherer]]s.<ref>{{Cite book |last1=Little |first1=Michael A. |chapter=Hunter-Gatherers |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780128026526000232 |title=Basics in Human Evolution |pages=323–335 |year=2015 |editor-last=Muehlenbein |editor-first=Michael P. |place=Boston |publisher=Academic Press |language=en |isbn=978-0-12-802652-6 |last2=Blumler |first2=Mark A. |access-date=30 July 2022 |archive-date=3 July 2022 |archive-url=https://web.archive.org/web/20220703085714/https://www.sciencedirect.com/science/article/pii/B9780128026526000232 |url-status=live }}</ref><ref>{{Cite book |last=Scarre |first=Chris |title=The Human Past: World Prehistory and the Development of Human Societies |publisher=Thames & Hudson |year=2018 |isbn=978-0-500-29335-5 |editor-last=Scarre |editor-first=Chris |edition=4th |location=London |pages=174–197 |chapter=The world transformed: from foragers and farmers to states and empires |author-link=Chris Scarre}}</ref> The [[History:Neolithic Revolution|Neolithic Revolution]] (the invention of [[Earth:Agriculture|agriculture]]) first took place in Southwest Asia and spread through large parts of the [[Earth:Old World|Old World]] over the following millennia.<ref>{{Cite book|vauthors=Colledge S, Conolly J, Dobney K, Manning K, Shennan S|url=https://www.worldcat.org/oclc/855969933|title=Origins and Spread of Domestic Animals in Southwest Asia and Europe.|date=2013|publisher=Left Coast Press|isbn=978-1-61132-324-5|location=Walnut Creek, CA|pages=13–17|oclc=855969933|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032846/https://www.worldcat.org/title/origins-and-spread-of-domestic-animals-in-southwest-asia-and-europe/oclc/855969933|url-status=live}}</ref> It also occurred independently in [[Place:Mesoamerica|Mesoamerica]] (about 6,000 years ago),<ref>{{cite book | vauthors = Scanes CG |date= January 2018 | chapter =The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture | veditors = Scanes CG, Toukhsati SR |title = Animals and Human Society |pages=103–131 |publisher= Elsevier |doi=10.1016/B978-0-12-805247-1.00006-X|isbn= 978-0-12-805247-1 }}</ref> China,<ref name="He2017">{{cite journal |vauthors=He K, Lu H, Zhang J, Wang C, Huan X |title=Prehistoric evolution of the dualistic structure mixed rice and millet farming in China |journal=The Holocene |date=7 June 2017 |volume=27 |issue=12 |pages=1885–1898 |doi=10.1177/0959683617708455 |bibcode=2017Holoc..27.1885H |s2cid=133660098 |url=https://www.researchgate.net/publication/317400332 |access-date=30 July 2022 |archive-date=20 November 2021 |archive-url=https://web.archive.org/web/20211120221221/https://www.researchgate.net/publication/317400332_Prehistoric_evolution_of_the_dualistic_structure_mixed_rice_and_millet_farming_in_China |url-status=live }}</ref><ref name="Lu">{{cite journal | vauthors = Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, Ye M, Zhang T, Zhang H, Yang X, Shen L, Xu D, Li Q | display-authors = 6 | title = Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 106 | issue = 18 | pages = 7367–7372 | date = May 2009 | pmid = 19383791 | pmc = 2678631 | doi = 10.1073/pnas.0900158106 | bibcode = 2009PNAS..106.7367L | doi-access = free }}</ref> Papua New Guinea,<ref>{{cite journal | vauthors = Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, Porch N, Winsborough B | display-authors = 6 | title = Origins of agriculture at Kuk Swamp in the highlands of New Guinea | journal = Science | volume = 301 | issue = 5630 | pages = 189–193 | date = July 2003 | pmid = 12817084 | doi = 10.1126/science.1085255 | s2cid = 10644185 | doi-access = free }}</ref> and the [[Place:Sahel|Sahel]] and [[Place:Sudanian savanna|West Savanna]] regions of Africa.<ref>{{cite journal | vauthors = Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, Otoo E, Sonké B, Dansi A, Djedatin G, Mariac C, Couderc M, Causse S, Alix K, Chaïr H, François O, Vigouroux Y | display-authors = 6 | title = Yam genomics supports West Africa as a major cradle of crop domestication | journal = Science Advances | volume = 5 | issue = 5 | pages = eaaw1947 | date = May 2019 | pmid = 31114806 | doi = 10.1126/sciadv.aaw1947 | pmc = 6527260 | bibcode = 2019SciA....5.1947S | doi-access = free }}</ref><ref>{{cite journal|vauthors=Winchell F|date=October 2017|title=Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group|journal=Current Anthropology|volume=58|issue=5|pages=673–683|doi=10.1086/693898|s2cid=149402650|url=https://discovery.ucl.ac.uk/id/eprint/1574602/7/Fuller_693898.pdf|access-date=30 July 2022|archive-date=23 June 2021|archive-url=https://web.archive.org/web/20210623152728/https://discovery.ucl.ac.uk/id/eprint/1574602/7/Fuller_693898.pdf|url-status=live}}</ref><ref>{{cite journal| vauthors = Manning K |date=February 2011|title=4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway |journal=Journal of Archaeological Science|volume=38|issue=2|pages=312–322|doi=10.1016/j.jas.2010.09.007 |bibcode=2011JArSc..38..312M }}</ref>

Access to food surplus led to the formation of permanent human settlements, the domestication of animals and the [[Chemistry:Chalcolithic|use of metal tools]] for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations.<ref>{{cite book|vauthors=Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E|url={{GBurl|id=Td4WAAAAQBAJ|q=western civilisation egypt|p=16}}|title=Cengage Advantage Books: Western Civilization: Beyond Boundaries|date=2013| publisher=Cengage Learning |isbn=978-1-285-66153-7|access-date=11 July 2015}}</ref><ref>{{cite book| vauthors = Spielvogel J |url={{GBurl|id=LceiAgAAQBAJ|q=western civilisation egypt|pg=PT65}}|title=Western Civilization: Volume A: To 1500|date=1 January 2014|publisher=Cenpage Learning|isbn=978-1-285-98299-1|access-date=11 July 2015}}</ref><ref>{{cite book|vauthors=Thornton B|url={{GBurl|id=fa6swJv64xkC|q=Greek Ways: How the Greeks Created Western Civilization}}|title=Greek Ways: How the Greeks Created Western Civilization|publisher=Encounter Books|year=2002|isbn=978-1-893554-57-3|location=San Francisco|pages=1–14|access-date=30 July 2022}}</ref>

===Ancient===
{{Main|History:Ancient history}}
[[File:All Gizah Pyramids.jpg|thumb|Great Pyramids of Giza, Egypt]]
An [[Social:Urban revolution|urban revolution]] took place in the [[History:4th millennium BC|4th millennium BCE]] with the development of [[Earth:City-state|city-state]]s, particularly Sumerian cities located in [[Place:Mesopotamia|Mesopotamia]].<ref>{{cite book|last=Garfinkle | first= Steven J. | chapter= Ancient Near Eastern City-States | editor1= Peter Fibiger Bang | editor1-link= Peter Fibiger Bang | editor2= Walter Scheidel | editor2-link= Walter Scheidel | title= The Oxford Handbook of the State in the Ancient Near East and Mediterranean | date= 2013 | publisher= Oxford Academic | doi= 10.1093/oxfordhb/9780195188318.013.0004 |isbn=978-0-19-518831-8 | pages= 94–119 }}</ref> It was in these cities that the earliest known form of writing, cuneiform script, appeared around 3000 BCE.<ref>{{cite book | vauthors = Woods C | chapter = The Emergence of Cuneiform Writing|date=28 February 2020 |title = A Companion to Ancient Near Eastern Languages|pages=27–46| veditors = Hasselbach-Andee R |edition=1st |publisher=Wiley|language=en|doi=10.1002/9781119193814.ch2|isbn=978-1-119-19329-6 | s2cid = 216180781}}</ref> Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation.<ref>{{cite journal | vauthors = Robinson A | title = Ancient civilization: Cracking the Indus script | journal = Nature | volume = 526 | issue = 7574 | pages = 499–501 | date = October 2015 | pmid = 26490603 | doi = 10.1038/526499a | bibcode = 2015Natur.526..499R | s2cid = 4458743 | doi-access = free }}</ref> They eventually traded with each other and invented technology such as wheels, plows and sails.<ref>{{cite book| vauthors = Crawford H |title=The Sumerian World|publisher=Routledge|year=2013|isbn=978-1-136-21911-5 |pages=447–461|chapter=Trade in the Sumerian world}}</ref><ref name="Bodnár-2018">{{cite journal|vauthors=Bodnár M|date=2018|title=Prehistoric innovations: Wheels and wheeled vehicles|url=https://www.ceeol.com/search/article-detail?id=714342|journal=Acta Archaeologica Academiae Scientiarum Hungaricae|language=English|volume=69|issue=2|pages=271–298|doi=10.1556/072.2018.69.2.3|s2cid=115685157|issn=0001-5210|access-date=30 July 2022|archive-date=23 June 2021|archive-url=https://web.archive.org/web/20210623152751/https://www.ceeol.com/search/article-detail?id=714342|url-status=live}}</ref><ref>{{cite journal|vauthors=Pryor FL|date=1985|title=The Invention of the Plow|url=https://www.jstor.org/stable/178600|journal=Comparative Studies in Society and History|volume=27|issue=4|pages=727–743|doi=10.1017/S0010417500011749|jstor=178600|s2cid=144840498|issn=0010-4175|access-date=30 July 2022|archive-date=9 April 2022|archive-url=https://web.archive.org/web/20220409092618/https://www.jstor.org/stable/178600|url-status=live}}</ref><ref name="Carter">{{cite book|vauthors=Carter R |url=https://www.academia.edu/1576775|title=A companion to the archaeology of the ancient Near East|publisher=Wiley-Blackwell|year=2012|isbn=978-1-4051-8988-0|veditors=Potts DT |location=Chichester, West Sussex|pages=347–354|chapter=19. [[Engineering:Watercraft|Watercraft]]|access-date=8 February 2014|archive-url=https://web.archive.org/web/20150428190743/https://www.academia.edu/1576775/Watercraft|archive-date=28 April 2015|url-status=live}}</ref> Astronomy and mathematics were also developed and the Great Pyramid of Giza was built.<ref>{{cite book| vauthors = Pedersen O |title=Early physics and astronomy: A historical introduction.|publisher=CUP Archive|year=1993|isbn=978-0-521-40340-5|page=1|chapter=Science Before the Greeks}}</ref><ref>{{cite book| vauthors = Robson E |title=Mathematics in ancient Iraq: A social history.|publisher=Princeton University Press|year=2008|pages=xxi}}</ref><ref>{{cite journal|vauthors=Edwards JF|date=2003|title=Building the Great Pyramid: Probable Construction Methods Employed at Giza|url=https://www.jstor.org/stable/25148110|journal=Technology and Culture|volume=44|issue=2|pages=340–354|doi=10.1353/tech.2003.0063|jstor=25148110|s2cid=109998651|issn=0040-165X|access-date=30 July 2022|archive-date=6 March 2022|archive-url=https://web.archive.org/web/20220306011135/https://www.jstor.org/stable/25148110|url-status=live}}</ref> There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations,<ref>{{cite journal | vauthors = Voosen P | title = New geological age comes under fire | journal = Science | volume = 361 | issue = 6402 | pages = 537–538 | date = August 2018 | pmid = 30093579 | doi = 10.1126/science.361.6402.537 | bibcode = 2018Sci...361..537V | s2cid = 51954326 }}</ref> with new ones appearing in the aftermath. [[History:Babylonia|Babylonia]]ns came to dominate Mesopotamia while others,<ref>{{cite book| vauthors = Saggs HW |title=Babylonians|publisher=Univ of California Press|year=2000|isbn=978-0-520-20222-1|page=7}}</ref> such as the Poverty Point culture, Minoans and the Shang dynasty, rose to prominence in new areas.<ref>{{cite journal| vauthors = Sassaman KE |date=1 December 2005|title=Poverty Point as Structure, Event, Process |journal=Journal of Archaeological Method and Theory|language=en|volume=12|issue=4|pages=335–364|doi=10.1007/s10816-005-8460-4|s2cid=53393440|issn=1573-7764}}</ref><ref>{{cite journal | vauthors = Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, Furtwängler A, Peltzer A, Posth C, Vasilakis A, McGeorge PJ, Konsolaki-Yannopoulou E, Korres G, Martlew H, Michalodimitrakis M, Özsait M, Özsait N, Papathanasiou A, Richards M, Roodenberg SA, Tzedakis Y, Arnott R, Fernandes DM, Hughey JR, Lotakis DM, Navas PA, Maniatis Y, Stamatoyannopoulos JA, Stewardson K, Stockhammer P, Pinhasi R, Reich D, Krause J, Stamatoyannopoulos G | display-authors = 6 | title = Genetic origins of the Minoans and Mycenaeans | journal = Nature | volume = 548 | issue = 7666 | pages = 214–218 | date = August 2017 | pmid = 28783727 | doi = 10.1038/nature23310 | pmc = 5565772 | bibcode = 2017Natur.548..214L }}</ref><ref>{{cite book| vauthors = Keightley DN |title=The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC |publisher=Cambridge University Press|year=1999|isbn=978-0-521-47030-8 | veditors = Loewe M, Shaughnessy EL |pages=232–291|chapter=The Shang: China's first historical dynasty}}</ref>

The [[History:Late Bronze Age collapse|Late Bronze Age collapse]] around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the [[History:Greek Dark Ages|Greek Dark Ages]].<ref>{{cite journal| vauthors = Kaniewski D, Guiot J, van Campo E |date=2015|title=Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review |journal=WIREs Climate Change |volume=6 |issue=4 |pages=369–382 |doi=10.1002/wcc.345 |bibcode=2015WIRCC...6..369K |s2cid=128460316}}</ref><ref>{{cite journal | vauthors = Drake BL |date=1 June 2012|title=The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages |journal=Journal of Archaeological Science |volume=39|issue=6|pages=1862–1870 |doi=10.1016/j.jas.2012.01.029 |bibcode=2012JArSc..39.1862D }}</ref> During this period iron started replacing bronze, leading to the [[History:Iron Age|Iron Age]].<ref>{{cite book | vauthors = Wells PS | title =European Prehistory| chapter =The Iron Age|date=2011 |pages=405–460| veditors = Milisauskas S |series=Interdisciplinary Contributions to Archaeology|place=New York, NY|publisher=Springer|language=en|doi=10.1007/978-1-4419-6633-9_11|isbn=978-1-4419-6633-9 }}</ref>

In the 5th century BCE, history started being [[History:Historiography|recorded as a discipline]], which provided a much clearer picture of life at the time.<ref>{{cite book| vauthors = Hughes-Warrington M |title=History as Wonder: Beginning with Historiography.|publisher=Taylor & Francis|year=2018|isbn=978-0-429-76315-1 |location=United Kingdom|chapter=Sense and non-sense in Ancient Greek histories}}</ref> Between the 8th and 6th century BCE, Europe entered the [[History:Classical antiquity|classical antiquity]] age, a period when {{wipe|Ancient Greece}} and [[History:Ancient Rome|ancient Rome]] flourished.<ref>{{cite web|date=2 October 2015|vauthors=Beard M|title=Why ancient Rome matters to the modern world|url=https://www.theguardian.com/books/2015/oct/02/mary-beard-why-ancient-rome-matters|access-date=17 April 2021|website=The Guardian|language=en|archive-date=14 April 2021|archive-url=https://web.archive.org/web/20210414130448/https://www.theguardian.com/books/2015/oct/02/mary-beard-why-ancient-rome-matters|url-status=live}}</ref><ref>{{cite web|vauthors=Vidergar AB|date=11 June 2015|title=Stanford scholar debunks long-held beliefs about economic growth in ancient Greece|url=https://news.stanford.edu/news/2015/june/greek-economy-growth-061115.html|access-date=17 April 2021|website=Stanford University|language=en|archive-date=18 April 2021|archive-url=https://web.archive.org/web/20210418190351/https://news.stanford.edu/news/2015/june/greek-economy-growth-061115.html|url-status=live}}</ref> Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create [[Astronomy:Maya calendar|complex calendars]].<ref>{{cite journal | vauthors = Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, García Hernández M, Beach T, Cagnato C, Aoyama K, Nasu H | display-authors = 6 | title = Monumental architecture at Aguada Fénix and the rise of Maya civilization | journal = Nature | volume = 582 | issue = 7813 | pages = 530–533 | date = June 2020 | pmid = 32494009 | doi = 10.1038/s41586-020-2343-4 | bibcode = 2020Natur.582..530I | s2cid = 219281856 }}</ref><ref>{{cite journal|vauthors=Milbrath S|date=March 2017|title=The Role of Solar Observations in Developing the Preclassic Maya Calendar|url=https://www.cambridge.org/core/product/identifier/S1045663516000043/type/journal_article|journal=Latin American Antiquity|language=en|volume=28|issue=1|pages=88–104|doi=10.1017/laq.2016.4|s2cid=164417025|issn=1045-6635|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://www.cambridge.org/core/journals/latin-american-antiquity/article/role-of-solar-observations-in-developing-the-preclassic-maya-calendar/CE9899861546A50ACE1819A6796D8694|url-status=live}}</ref> In Africa, the [[History:Kingdom of Aksum|Kingdom of Aksum]] overtook the declining [[History:Kingdom of Kush|Kingdom of Kush]] and facilitated trade between India and the Mediterranean.<ref>{{cite journal|vauthors=Benoist A, Charbonnier J, Gajda I|date=2016|title=Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida|url=https://www.jstor.org/stable/45163415|journal=Proceedings of the Seminar for Arabian Studies|volume=46|pages=25–40|jstor=45163415|issn=0308-8421|access-date=30 July 2022|archive-date=28 April 2022|archive-url=https://web.archive.org/web/20220428202622/https://www.jstor.org/stable/45163415|url-status=live}}</ref> In West Asia, the [[Place:Achaemenid Empire|Achaemenid Empire]]'s system of centralized governance became the precursor to many later empires,<ref>{{cite journal| vauthors = Farazmand A |date=1 January 1998|title=Administration of the Persian achaemenid world-state empire: implications for modern public administration |journal=International Journal of Public Administration|volume=21|issue=1|pages=25–86|doi=10.1080/01900699808525297|issn=0190-0692}}</ref> while the [[History:Gupta Empire|Gupta Empire]] in India and the Han dynasty in China have been described as golden ages in their respective regions.<ref>{{cite journal|vauthors=Ingalls DH|date=1976|title=Kālidāsa and the Attitudes of the Golden Age|url=https://www.jstor.org/stable/599886|journal=Journal of the American Oriental Society|volume=96|issue=1|pages=15–26|doi=10.2307/599886|jstor=599886|issn=0003-0279|access-date=30 July 2022|archive-date=9 April 2022|archive-url=https://web.archive.org/web/20220409092718/https://www.jstor.org/stable/599886|url-status=live}}</ref><ref>{{cite journal|vauthors=Xie J|date=2020|title=Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty|url=https://www.cambridge.org/core/product/identifier/S0066622X20000015/type/journal_article|journal=Architectural History|language=en|volume=63|pages=1–36|doi=10.1017/arh.2020.1|s2cid=229716130|issn=0066-622X|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032850/https://www.cambridge.org/core/journals/architectural-history/article/abs/pillars-of-heaven-the-symbolic-function-of-column-and-bracket-sets-in-the-han-dynasty/1B1C1C007216E36004F15A1B7D61C87F|url-status=live}}</ref>

===Medieval===
{{Main|History:Post-classical history}}
[[File:Cleric-Knight-Workman.jpg|Medieval French [[Engineering:Illuminated manuscript|manuscript illustration]] of the three classes of medieval society from the 13th-century {{lang|fr|Li Livres dou Santé}}|thumb|right|upright]]
Following the fall of the Western Roman Empire in 476, Europe entered the [[History:Middle Ages|Middle Ages]].<ref>{{cite journal| vauthors = Marx W, Haunschild R, Bornmann L |date=2018|title=Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question|journal=Climate|language=en|volume=6|issue=4|page=90|doi=10.3390/cli6040090|bibcode=2018Clim....6...90M |doi-access=free}}</ref> During this period, [[Religion:Christianity|Christianity]] and the [[Organization:Catholic Church|Church]] would provide centralized authority and education.<ref name="Oxford University Press">{{cite book|veditors=Brooke JH, Numbers RL|title=Science and Religion Around the World|date=2011|publisher=Oxford University Press|location=New York|isbn=978-0-19-532819-6|page=72|url={{GBurl|id=W6HPW1TodZwC|p=71}}|access-date=30 July 2022}}</ref> In the Middle East, [[Religion:Islam|Islam]] became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age, inspiring achievements in architecture, the revival of old advances in science and technology, and the formation of a distinct way of life.<ref name="Renima-2016">{{cite book | vauthors = Renima A, Tiliouine H, Estes RJ | title = The State of Social Progress of Islamic Societies| chapter = The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization|date=2016 |pages=25–52| veditors = Tiliouine H, Estes RJ |series=International Handbooks of Quality-of-Life|place=Cham|publisher=Springer International Publishing|language=en|doi=10.1007/978-3-319-24774-8_2|isbn=978-3-319-24774-8 }}</ref><ref>{{Cite book|title=The Harper Atlas of World History| vauthors = Vidal-Nanquet P |publisher=Harper & Row Publishers|year=1987|page=76}}</ref> The [[Religion:Christendom|Christian]] and Islamic worlds would eventually clash, with the [[History:Kingdom of England|Kingdom of England]], the [[History:Kingdom of France|Kingdom of France]] and the [[Religion:Holy Roman Empire|Holy Roman Empire]] declaring a series of [[Religion:Crusades|holy wars]] to regain control of the [[Religion:Holy Land|Holy Land]] from [[Religion:Muslim|Muslim]]s.<ref>{{cite book| vauthors = Asbridge T |title=The Crusades: The War for the Holy Land|publisher=Simon and Schuster|year=2012|isbn=978-1-84983-770-5|chapter=Introduction: The world of the crusades}}</ref>

In the Americas, complex Mississippian societies would arise starting around 800 CE,<ref>{{Cite encyclopedia|url= https://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-707|author= Adam King|title= Mississippian Period: Overview|encyclopedia= New Georgia Encyclopedia|date= 2002|access-date= 15 November 2009|archive-date= 19 August 2009|archive-url= https://web.archive.org/web/20090819042104/http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-707|url-status= dead}}</ref> while further south, the Aztecs and Incas would become the dominant powers.<ref>{{cite book| vauthors = Conrad G, Demarest AA |title=Religion and Empire: The Dynamics of Aztec and Inca Expansionism|publisher=Cambridge University Press|year=1984|isbn=0-521-31896-3|page=2}}</ref> The Mongol Empire would conquer much of [[Earth:Eurasia|Eurasia]] in the 13th and 14th centuries.<ref>{{cite book| vauthors = May T |title=The Mongol Conquests in World History| publisher=Reaktion Books |year=2013|isbn=978-1-86189-971-2 |page=7}}</ref> Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast.<ref>{{Cite encyclopedia|vauthors=Canós-Donnay S|title=The Empire of Mali|date=25 February 2019|url=https://oxfordre.com/africanhistory/view/10.1093/acrefore/9780190277734.001.0001/acrefore-9780190277734-e-266|encyclopedia=Oxford Research Encyclopedia of African History|publisher=Oxford University Press|language=en|doi=10.1093/acrefore/9780190277734.013.266|isbn=978-0-19-027773-4|access-date=7 May 2021|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020034919/https://oxfordre.com/africanhistory/view/10.1093/acrefore/9780190277734.001.0001/acrefore-9780190277734-e-266|url-status=live}}</ref> Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific.<ref>{{cite journal| vauthors = Canela SA, Graves MW |title=The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity|journal=Asian Perspectives|volume=37|issue=2|pages=135–164|url=https://www.researchgate.net/publication/46734826}}</ref>

===Modern===
{{Main|History:Early modern period|History:Late modern period}}
[[File:Maquina vapor Watt ETSIIM.jpg|thumb|James Watt's steam engine]]
The [[History:Early modern period|early modern period]] in Europe and the Near East ({{Circa|1450}}–1800) began with the final defeat of the Byzantine Empire, and the [[Place:Ottoman Empire|rise of the Ottoman Empire]].<ref>{{cite book|chapter=Ottomans and Europe|date=1 January 1994|chapter-url=https://brill.com/view/book/edcoll/9789004391659/BP000019.xml|title=Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation|pages=589–635|veditors=Brady T, Oberman T, Tracy JD|publisher=Brill|doi=10.1163/9789004391659_019|isbn=978-90-04-39165-9|access-date=17 April 2021|archive-date=2 May 2022|archive-url=https://web.archive.org/web/20220502073325/https://brill.com/view/book/edcoll/9789004391659/BP000019.xml|url-status=live|last1=Kafadar |first1=Cemal }}</ref> Meanwhile, Japan entered the Edo period,<ref>{{Cite encyclopedia|vauthors=Goree R|title=The Culture of Travel in Edo-Period Japan|date=19 November 2020|url=https://oxfordre.com/asianhistory/view/10.1093/acrefore/9780190277727.001.0001/acrefore-9780190277727-e-72|encyclopedia=Oxford Research Encyclopedia of Asian History|publisher=Oxford University Press|language=en|doi=10.1093/acrefore/9780190277727.013.72|isbn=978-0-19-027772-7|access-date=7 May 2021|archive-date=12 August 2021|archive-url=https://web.archive.org/web/20210812150712/https://oxfordre.com/asianhistory/view/10.1093/acrefore/9780190277727.001.0001/acrefore-9780190277727-e-72|url-status=live}}</ref> the Qing dynasty rose in China<ref>{{Cite journal|vauthors=Mosca MW|date=2010|title=CHINA'S LAST EMPIRE: The Great Qing|url=https://www.proquest.com/openview/a516602ac28aba8955507e46ab41483e/1?pq-origsite=gscholar&cbl=25135|journal=Pacific Affairs|volume=83|access-date=30 July 2022|archive-date=6 March 2022|archive-url=https://web.archive.org/web/20220306014457/https://www.proquest.com/openview/a516602ac28aba8955507e46ab41483e/1?pq-origsite=gscholar&cbl=25135|url-status=live}}</ref> and the Mughal Empire ruled much of India.<ref>{{Cite journal|vauthors=Suyanta S, Ikhlas S|date=19 July 2016|title=Islamic Education at Mughal Kingdom in India (1526–1857)|url=https://journal.tarbiyahiainib.ac.id/index.php/attalim/article/view/228|journal=Al-Ta Lim Journal|volume=23|issue=2|pages=128–138|doi=10.15548/jt.v23i2.228|issn=2355-7893|access-date=30 July 2022|archive-date=7 April 2022|archive-url=https://web.archive.org/web/20220407082504/http://journal.tarbiyahiainib.ac.id/index.php/attalim/article/view/228|url-status=live|doi-access=free}}</ref> Europe underwent the [[Philosophy:Renaissance|Renaissance]], starting in the 15th century,<ref>{{cite book|vauthors=Kirkpatrick R|url=https://www.worldcat.org/oclc/893909816|title=The European Renaissance, 1400–1600|date=2002|isbn=978-1-317-88646-4|page=1|oclc=893909816|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032848/https://www.worldcat.org/title/european-renaissance-1400-1600/oclc/893909816|url-status=live}}</ref> and the [[Age of Discovery]] began with the exploring and [[Social:Colonialism|colonizing]] of new regions.<ref>{{cite book|vauthors=Arnold D|url=https://www.worldcat.org/oclc/859536800|title=The Age of Discovery, 1400–1600|date=2002|isbn=978-1-136-47968-7|edition=Second|pages=xi|oclc=859536800|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032848/https://www.worldcat.org/title/age-of-discovery-1400-1600/oclc/859536800|url-status=live}}</ref> This includes the [[Place:British Empire|British Empire]] expanding to become the world's largest empire<ref>{{cite journal|vauthors=Palan R|date=14 January 2010|title=International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics|url=https://www.degruyter.com/document/doi/10.2202/1565-3404.1239/html|journal=Theoretical Inquiries in Law|volume=11|issue=1|doi=10.2202/1565-3404.1239|s2cid=56216309|issn=1565-3404|access-date=30 July 2022|archive-date=26 August 2021|archive-url=https://web.archive.org/web/20210826211616/https://www.degruyter.com/document/doi/10.2202/1565-3404.1239/html|url-status=live}}</ref> and [[History:European colonization of the Americas|the colonization of the Americas]].<ref>{{cite journal| vauthors = Dixon EJ |date= January 2001 |title=Human colonization of the Americas: timing, technology and process |journal=Quaternary Science Reviews|language=en|volume=20|issue=1–3 |pages=277–299|doi=10.1016/S0277-3791(00)00116-5|bibcode= 2001QSRv...20..277J }}</ref> This expansion led to the [[History:Atlantic slave trade|Atlantic slave trade]]<ref>{{Cite journal |vauthors=Lovejoy PE |date=1989 |title=The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature |url=https://www.jstor.org/stable/182914 |journal=The Journal of African History |volume=30 |issue=3 |pages=365–394 |doi=10.1017/S0021853700024439 |jstor=182914 |s2cid=161321949 |issn=0021-8537 |access-date=30 July 2022 |archive-date=6 March 2022 |archive-url=https://web.archive.org/web/20220306011109/https://www.jstor.org/stable/182914 |url-status=live }}</ref> and the genocide of Native American peoples.<ref>{{cite book | vauthors = Cave AA | chapter = Genocide in the Americas|date=2008 | title = The Historiography of Genocide|pages=273–295 | veditors = Stone D |place=London|publisher=Palgrave Macmillan UK|language=en|doi=10.1057/9780230297784_11|isbn=978-0-230-29778-4}}</ref> This period also marked the Scientific Revolution, with great advances in [[Mathematics|mathematics]], [[Physics:Mechanics|mechanics]], [[Astronomy:Astronomy|astronomy]] and [[Biology:Physiology|physiology]].<ref>{{cite journal | vauthors = Delisle RG | title = Can a revolution hide another one? Charles Darwin and the Scientific Revolution | journal = Endeavour | volume = 38 | issue = 3–4 | pages = 157–158 | date = September 2014 | pmid = 25457642 | doi = 10.1016/j.endeavour.2014.10.001 }}</ref>

The [[History:Late modern period|late modern period]] (1800–present) saw the Technological and [[History:Industrial Revolution|Industrial Revolution]] bring such discoveries as [[Engineering:Imaging technology|imaging technology]], major innovations in transport and [[Physics:Energy development|energy development]].<ref>{{cite web|title=Greatest Engineering Achievements of the 20th Century|url=https://www.greatachievements.org/|url-status=live|archive-url=https://web.archive.org/web/20150406160644/https://greatachievements.org/|archive-date=6 April 2015|access-date=7 April 2015| work = National Academy of Engineering }}</ref> The {{wipe|United States}} underwent great change, going from a small group of colonies to one of the global superpowers.<ref>{{Cite book|vauthors=Herring GC|url=https://www.worldcat.org/oclc/299054528|title=From colony to superpower : U.S. foreign relations since 1776|date=2008|publisher=Oxford University Press|isbn=978-0-19-972343-0|location=New York|page=1|oclc=299054528|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://www.worldcat.org/title/from-colony-to-superpower-us-foreign-relations-since-1776/oclc/299054528|url-status=live}}</ref> The Napoleonic Wars raged through Europe in the early 1800s,<ref>{{Cite journal|vauthors=O'Rourke KH|date=March 2006|title=The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815|url=https://www.cambridge.org/core/product/identifier/S1740022806000076/type/journal_article|journal=Journal of Global History|language=en|volume=1|issue=1|pages=123–149|doi=10.1017/S1740022806000076|issn=1740-0228|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032852/https://www.cambridge.org/core/journals/journal-of-global-history/article/abs/worldwide-economic-impact-of-the-french-revolutionary-and-napoleonic-wars-17931815/B5D21C47E53307E78358803D4695FCE8|url-status=live}}</ref> Spain lost most of its colonies in the [[Earth:New World|New World]],<ref>{{Cite journal|vauthors=Zimmerman AF|date=November 1931|title=Spain and Its Colonies, 1808–1820|url=https://www.jstor.org/stable/2506251|journal=The Hispanic American Historical Review|volume=11|issue=4|pages=439–463|doi=10.2307/2506251|jstor=2506251|access-date=30 July 2022|archive-date=6 March 2022|archive-url=https://web.archive.org/web/20220306014948/https://www.jstor.org/stable/2506251|url-status=live}}</ref> while Europeans continued [[Earth:Scramble for Africa|expansion into Africa]]{{snd}}where European control went from 10% to almost 90% in less than 50 years<ref>{{cite web |date=2011 |title=British History in depth: Slavery and the 'Scramble for Africa' |url=https://www.bbc.co.uk/history/british/abolition/scramble_for_africa_article_01.shtml |url-status=live |archive-url=https://web.archive.org/web/20220324121231/https://www.bbc.co.uk/history/british/abolition/scramble_for_africa_article_01.shtml |archive-date=24 March 2022 |access-date=5 May 2021 |website=BBC |language=en-GB |vauthors=David S}}</ref>{{snd}}and Oceania.<ref>{{Cite journal |vauthors=Raudzens G |date=2004 |title=The Australian Frontier Wars, 1788–1838 (review) |url=https://dx.doi.org/10.1353/jmh.2004.0138 |journal=The Journal of Military History |volume=68 |issue=3 |pages=957–959 |doi=10.1353/jmh.2004.0138 |issn=1543-7795 |s2cid=162259092}}</ref>

A tenuous [[Social:Balance of power (international relations)|balance of power]] among European nations collapsed in 1914 with the outbreak of the [[Social:World War I|First World War]], one of the deadliest conflicts in history.<ref>{{Cite book|vauthors=Clark CM|url=https://www.worldcat.org/oclc/794136314|title=The sleepwalkers : how Europe went to war in 1914|date=2012|publisher=Allen Lane|isbn=978-0-7139-9942-6|location=London|chapter=Polarization of Europe, 1887–1907|oclc=794136314|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://www.worldcat.org/title/sleepwalkers-how-europe-went-to-war-in-1914/oclc/794136314|url-status=live}}</ref> In the 1930s, [[Finance:Great Depression|a worldwide economic crisis]] led to the rise of authoritarian regimes and a [[Social:World War II|Second World War]], involving almost all of the world's countries.<ref>{{cite book |author=Robert Dahl |title=Democracy and Its Critics |url=https://archive.org/details/democracyitscrit00dahl_0 |url-access=registration |year=1989 |publisher=Yale UP |pages=[https://archive.org/details/democracyitscrit00dahl_0/page/239 239–240] |isbn=0-300-15355-4}}</ref> The war's destruction led to the collapse of most global empires, leading to widespread decolonization.

===Contemporary===
{{Main|History:Contemporary history}}
Following the conclusion of the Second World War in 1945, the [[History:Cold War|Cold War]] between the USSR and the United States saw a struggle for global influence, including a [[Engineering:Nuclear arms race|nuclear arms race]] and a [[Astronomy:Space Race|space race]], ending in the collapse of the Soviet Union.<ref>{{Cite journal| vauthors = McDougall WA |date=May 1985|title=Sputnik, the space race, and the Cold War|url=https://www.tandfonline.com/doi/full/10.1080/00963402.1985.11455962|journal=Bulletin of the Atomic Scientists|language=en|volume=41|issue=5|pages=20–25|doi=10.1080/00963402.1985.11455962|bibcode=1985BuAtS..41e..20M|issn=0096-3402}}</ref><ref>{{Cite journal|vauthors=Plous S|date=May 1993|title=The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?|url=https://journals.sagepub.com/doi/10.1177/0022343393030002004|journal=Journal of Peace Research|language=en|volume=30|issue=2|pages=163–179|doi=10.1177/0022343393030002004|s2cid=5482851|issn=0022-3433|access-date=30 July 2022|archive-date=21 February 2022|archive-url=https://web.archive.org/web/20220221155825/https://journals.sagepub.com/doi/10.1177/0022343393030002004|url-status=live}}</ref> The current [[Philosophy:Information Age|Information Age]], spurred by the development of the [[Internet]] and [[Artificial intelligence|Artificial Intelligence]] systems, sees the world becoming increasingly [[Social:Globalization|globalized]] and interconnected.<ref>{{Cite journal|vauthors=Sachs JD|date=April 2017|title=Globalization{{snd}}In the Name of Which Freedom?|url=https://link.springer.com/10.1007/s41463-017-0019-5|journal=Humanistic Management Journal|language=en|volume=1|issue=2|pages=237–252|doi=10.1007/s41463-017-0019-5|s2cid=133030709|issn=2366-603X|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://link.springer.com/article/10.1007/s41463-017-0019-5|url-status=live|doi-access=free}}</ref>

== Habitat and population ==
{{Further|Social:Human geography| Demography}}
{{Infobox
| image            = [[File:Global population cartogram.png|thumb|upright=2.05
| Mosaic [[Cartogram|cartogram]] showing the distribution of the global population based on 2018 UN data. Each of the 15,266 pixels represents the home country of 500,000 people – cartogram by Max Roser for [[Organization:Our World in Data|Our World in Data]]]]

| image2            = [[File:Population Density, v4.11, 2020 (48009093621).jpg|thumb|upright=2.05
| Choropleth showing [[Earth:Population density|Population density]] (people per square kilometer) estimates by 30 arc-second grid in 2020]]
| title            = Population statistics{{#tag:ref|The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects.<ref>{{cite web |url=https://www.cia.gov/the-world-factbook/countries/world |title=World |work=The World Factbook |publisher=CIA |date=17 May 2016 |access-date=2 October 2016 |archive-date=26 January 2021 |archive-url=https://web.archive.org/web/20210126032610/https://www.cia.gov/the-world-factbook/countries/world/ |url-status=live }}</ref><ref>{{cite web |url=https://esa.un.org/unpd/wpp/Publications/Files/WPP2017_KeyFindings.pdf |publisher=United Nations, Department of Economic and Social Affairs, Population Division |date=2017 |title=World Population Prospects: The 2017 Revision |page=2&17 |access-date=30 July 2022 |archive-date=26 June 2019 |archive-url=https://web.archive.org/web/20190626225001/https://esa.un.org/unpd/wpp/Publications/Files/WPP2017_KeyFindings.pdf |url-status=live }}</ref>|group=n}}
| label1           = World population
| data1            = {{#expr: {{data world|poptoday}} / 1e9 round 1}}&nbsp;billion
| label2           = [[Earth:Population density#Human population density|Population density]]
| data2            = {{Pop density|{{data world|poptoday}}|{{data world|pst2|total area}}|km2|sqmi|prec=0}} by total area<br />{{Pop density|{{data world|poptoday}}|{{data world|pst2|land area}}|km2|sqmi|prec=0}} by land area
| label3           = Largest cities{{#tag:ref|Cities with over 10 million inhabitants as of 2018.<ref>{{cite news|title=The World's Cities in 2018|url=https://www.un.org/en/events/citiesday/assets/pdf/the_worlds_cities_in_2018_data_booklet.pdf|access-date=|newspaper={{wipe|United Nations}}|archive-date=1 November 2018|archive-url=https://web.archive.org/web/20181101135338/http://www.un.org/en/development/desa/population/publications/pdf/urbanization/the_worlds_cities_in_2018_data_booklet.pdf|url-status=live}}</ref>|group=n}}
| data3            = [[Place:Tokyo|Tokyo]], [[Place:Delhi|Delhi]], [[Place:Shanghai|Shanghai]], São Paulo, [[Place:Mexico City|Mexico City]], [[Place:Cairo|Cairo]], {{wipe|Mumbai}}, [[Place:Beijing|Beijing]], [[Place:Dhaka|Dhaka]], {{wipe|Osaka}}, {{wipe|New York City}}-Newark, [[Place:Karachi|Karachi]], [[Place:Buenos Aires|Buenos Aires]], [[Place:Chongqing|Chongqing]], Istanbul, [[Place:Kolkata|Kolkata]], [[Place:Manila|Manila]], [[Place:Lagos|Lagos]], Rio de Janeiro, [[Place:Tianjin|Tianjin]], [[Place:Kinshasa|Kinshasa]], Guangzhou, {{wipe|Los Angeles}}-Long Beach-Santa Ana, [[Place:Moscow|Moscow]], Shenzhen, Lahore, Bangalore, [[Place:Paris|Paris]], [[Place:Jakarta|Jakarta]], Chennai, [[Place:Lima|Lima]], [[Place:Bogotá|Bogota]], [[Place:Bangkok|Bangkok]], [[Place:London|London]]
}}

Early human settlements were dependent on proximity to [[Earth:Water resources|water]] and{{snd}}depending on the lifestyle{{snd}}other [[Social:Natural resource|natural resource]]s used for subsistence, such as populations of animal prey for hunting and arable land for growing crops and grazing livestock.<ref>{{cite book|vauthors=Rector RK|url=https://www.worldcat.org/oclc/953735302|title=The Early River Valley Civilizations|date=2016|isbn=978-1-4994-6329-3|edition=First|location=New York|page=10|oclc=953735302|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://www.worldcat.org/title/early-river-valley-civilizations/oclc/953735302|url-status=live |publisher=Rosen Publishing }}</ref> Modern humans, however, have a great capacity for altering their habitats by means of technology, [[Earth:Irrigation|irrigation]], [[Engineering:Urban planning|urban planning]], construction, deforestation and [[Earth:Desertification|desertification]].<ref>{{cite web |url=https://www.westerville.k12.oh.us/userfiles/4188/Classes/7526/humanforcesthatchangeenvironment.pdf?id=448117 |title=How People Modify the Environment |author=<!--Not stated--> |publisher=Westerville City School District |access-date=13 March 2019 |archive-date=25 February 2021 |archive-url=https://web.archive.org/web/20210225132108/http://www.westerville.k12.oh.us/userfiles/4188/Classes/7526/humanforcesthatchangeenvironment.pdf?id=448117 |url-status=live }}</ref> Human settlements continue to be vulnerable to natural disasters, especially those placed in hazardous locations and with low quality of construction.<ref>{{cite web |url=https://siteresources.worldbank.org/INTLACREGTOPHAZMAN/Resources/EN_Breve_Oct03_32_Nat_Dis_EN.pdf |title=Natural disasters and the urban poor |publisher=[[Organization:World Bank|World Bank]] |date=October 2003 |url-status=live |archive-url=https://web.archive.org/web/20170809063303/https://siteresources.worldbank.org/INTLACREGTOPHAZMAN/Resources/EN_Breve_Oct03_32_Nat_Dis_EN.pdf |archive-date=9 August 2017 }}</ref> Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving [[Social:Aesthetics|aesthetics]], increasing knowledge or enhancing the exchange of resources.<ref>{{cite book|vauthors=Habitat UN|url=https://www.worldcat.org/oclc/889953315|title=The state of the world's cities 2012 / prosperity of cities.|date=2013|publisher=Routledge|isbn=978-1-135-01559-6|location=[London]|pages=x|oclc=889953315|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032849/https://www.worldcat.org/title/state-of-the-worlds-cities-2012-prosperity-of-cities/oclc/889953315|url-status=live}}</ref>

Humans are one of the most [[Biology:Adaptation|adaptable]] species, despite having a low or narrow tolerance for many of the earth's extreme environments.<ref name="Piantadosi-2003">{{cite book|vauthors=Piantadosi CA|url=https://www.worldcat.org/oclc/70215878|title=The biology of human survival : life and death in extreme environments|date=2003|publisher=Oxford University Press|isbn=978-0-19-974807-5|location=Oxford|pages=2–3|oclc=70215878|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730032850/https://www.worldcat.org/title/biology-of-human-survival-life-and-death-in-extreme-environments/oclc/70215878|url-status=live}}</ref> By using advanced tools and clothing, humans have been able to extend their tolerance to a wide variety of temperatures, [[Physics:Humidity|humidities]], and altitudes.<ref name="Piantadosi-2003" /><ref>{{cite journal |last1=Toups |first1=M.A. |last2=Kitchen |first2=A. |last3=Light |first3=J.E. |last4=Reed |first4=D.L. |year=2011 |title=Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa |journal=Molecular Biology and Evolution |volume=28 |issue=1 |pages=29–32 |doi=10.1093/molbev/msq234 |pmc=3002236 |pmid=20823373}}</ref> As a result, humans are a [[Biology:Cosmopolitan distribution|cosmopolitan]] species found in almost all regions of the world, including [[Earth:Tropical rainforest|tropical rainforest]], [[Earth:Desert|arid desert]], extremely cold arctic regions, and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability.<ref name="adapt1">{{cite web |vauthors=O'Neil D |title=Human Biological Adaptability; Overview |url=https://anthro.palomar.edu/adapt/adapt_1.htm |url-status=dead |archive-url=https://web.archive.org/web/20130306124405/https://anthro.palomar.edu/adapt/adapt_1.htm |archive-date=6 March 2013 |access-date=6 January 2013 |publisher=Palomar College}}</ref> The human population is not, however, uniformly distributed on the [[Astronomy:Earth|Earth]]'s surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like [[Earth:Antarctica|Antarctica]] and vast swathes of the ocean.<ref name="Piantadosi-2003" /><ref>{{cite web |url=https://www.bbc.co.uk/schools/gcsebitesize/geography/population/population_distribution_rev1.shtml |publisher=BBC |title=Population distribution and density |url-status=dead |archive-url=https://web.archive.org/web/20170623234027/https://www.bbc.co.uk/schools/gcsebitesize/geography/population/population_distribution_rev1.shtml |archive-date=23 June 2017 |access-date=26 June 2017 }}</ref> Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).<ref>{{cite journal |vauthors=Bunn SE, Arthington AH |title=Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity |journal=Environmental Management |volume=30 |issue=4 |pages=492–507 |date=October 2002 |pmid=12481916 |doi=10.1007/s00267-002-2737-0 |hdl-access=free |s2cid=25834286 |hdl=10072/6758}}</ref>

Within the last century, humans have explored challenging environments such as Antarctica, the [[Earth:Deep sea|deep sea]], and [[Astronomy:Outer space|outer space]].<ref name="Heim-1991">{{cite journal |vauthors=Heim BE |year=1990–1991 |title=Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica |url=https://heinonline.org/HOL/Page?handle=hein.journals/vantl23&id=831&div=&collection= |journal=Vanderbilt Journal of Transnational Law |volume=23 |page=819 |access-date=30 July 2022 |archive-date=23 June 2021 |archive-url=https://web.archive.org/web/20210623152719/https://heinonline.org/HOL/Page?handle=hein.journals%2Fvantl23&id=831&div=&collection= |url-status=live}}</ref> Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to [[Science|scientific]], military, or industrial expeditions.<ref name="Heim-1991" /> Humans have briefly visited the [[Astronomy:Exploration of the Moon|Moon]] and made their presence felt on other [[Astronomy:Astronomical object|celestial bodies]] through human-made [[Engineering:Robotic spacecraft|robotic spacecraft]].<ref>{{cite web |url=https://www.jpl.nasa.gov/missions/mars-science-laboratory-curiosity-rover-msl/ |title=Mission to Mars: Mars Science Laboratory Curiosity Rover |publisher=Jet Propulsion Laboratory |access-date=26 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20150818014850/https://www.jpl.nasa.gov/missions/mars-science-laboratory-curiosity-rover-msl |archive-date=18 August 2015 }}</ref><ref>{{cite web |url=https://www.esa.int/Our_Activities/Space_Science/Rosetta/Touchdown!_Rosetta_s_Philae_probe_lands_on_comet |title=Touchdown! Rosetta's Philae probe lands on comet |date=12 November 2014 |publisher=European Space Agency |access-date=26 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20150822055902/https://www.esa.int/Our_Activities/Space_Science/Rosetta/Touchdown!_Rosetta_s_Philae_probe_lands_on_comet |archive-date=22 August 2015 }}</ref><ref>{{cite web |url=https://science.nasa.gov/missions/near/ |title=NEAR-Shoemaker |publisher=[[Organization:NASA|NASA]] |access-date=26 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20150826173835/https://science.nasa.gov/missions/near/ |archive-date=26 August 2015 }}</ref> Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, [[Astronomy:Human presence in space|in space]] through habitation on the [[Astronomy:International Space Station|International Space Station]].<ref name="urlNASA">{{cite web |vauthors=Kraft R |title=JSC celebrates ten years of continuous human presence aboard the International Space Station |url=https://www.jsc.nasa.gov/jscfeatures/articles/000000945.html |publisher=[[Organization:Johnson Space Center|Johnson Space Center]] |work=JSC Features |date=11 December 2010 |url-status=dead |archive-url=https://web.archive.org/web/20120216221409/https://www.jsc.nasa.gov/jscfeatures/articles/000000945.html |archive-date=16 February 2012 |access-date=13 February 2012 }}</ref>

[[File:Distribution-of-earths-mammals.png|thumb|upright=1.5| Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%.<ref name="Bar-On" />]]

Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million.<ref>{{cite book |vauthors=Tellier LN |url={{GBurl|id=cXuCjDbxC1YC|p=26}} |title=Urban world history: an economic and geographical perspective |date=2009 |isbn=978-2-7605-1588-8 |page=26 |publisher=Presses de l'Université du Québec |access-date=30 July 2022}}</ref><ref>{{cite book |vauthors=Thomlinson R |title=Demographic problems; controversy over population control. |date=1975 |edition=2nd |publisher=Dickenson Pub. Co |location=Ecino, CA |isbn=978-0-8221-0166-6}}</ref> Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD.<ref>{{cite web |vauthors=Harl KW |date=1998 |title=Population estimates of the Roman Empire |url=https://www.tulane.edu/~august/H303/handouts/Population.htm |archive-url=https://web.archive.org/web/20160507061006/https://www.tulane.edu/~august/H303/handouts/Population.htm|archive-date=7 May 2016|access-date=8 December 2012|publisher=Tulane.edu}}</ref> [[Medicine:Bubonic plague|Bubonic plague]]s, first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in [[Earth:Eurasia|Eurasia]] and [[Place:North Africa|North Africa]] alone.<ref>{{cite journal |vauthors=Zietz BP, Dunkelberg H | title = The history of the plague and the research on the causative agent Yersinia pestis |journal = International Journal of Hygiene and Environmental Health |volume=207 |issue=2 |pages=165–178 | date = February 2004 | pmid = 15031959 | doi = 10.1078/1438-4639-00259 |pmc=7128933}}</ref> Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999.<ref>{{cite news |url=https://news.bbc.co.uk/1/hi/sci/tech/411162.stm |access-date=5 February 2008 |work=BBC News |title=World's population reaches six billion |date=5 August 1999 |url-status=live |archive-url=https://web.archive.org/web/20080415053354/https://news.bbc.co.uk/1/hi/sci/tech/411162.stm |archive-date=15 April 2008 }}</ref> It passed seven billion in 2011<ref>{{Cite web |author=United Nations |title=World population to reach 8 billion on 15 November 2022 |url=https://www.un.org/en/desa/world-population-reach-8-billion-15-november-2022 |access-date=27 October 2022 |website=United Nations |language=en}}</ref> and passed eight billion in November 2022.<ref>{{cite journal |url=https://www.nature.com/articles/d41586-022-03792-4 |date=23 November 2022 |title=Eight billion people, SARS-CoV-2 ancestor and illegal fishing |journal=Nature |volume=611 |issue=641 |page=641 |doi=10.1038/d41586-022-03792-4 |bibcode=2022Natur.611..641. |s2cid=253764233 |access-date=26 January 2023 }}</ref> It took over two million years of [[History:Prehistory|human prehistory]] and [[History:Human history|history]] for the human population to reach one [[Billion|billion]] and only 207 years more to grow to 7 billion.<ref>{{cite web |date=27 October 2011 |title=World Population to Hit Milestone With Birth of 7 Billionth Person |url=https://www.pbs.org/newshour/bb/world-july-dec11-population1_10-27/ |url-status=live |archive-url=https://web.archive.org/web/20170924090953/http://www.pbs.org/newshour/bb/world-july-dec11-population1_10-27/ |archive-date=24 September 2017 |access-date=11 February 2018 |website=PBS NewsHour}}</ref> The combined [[Earth:Biomass (ecology)|biomass]] of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals.<ref name="Bar-On">{{cite journal | vauthors = Bar-On YM, Phillips R, Milo R | title = The biomass distribution on Earth | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 115 | issue = 25 | pages = 6506–6511 | date = June 2018 | pmid = 29784790 | pmc = 6016768 | doi = 10.1073/pnas.1711842115 | bibcode = 2018PNAS..115.6506B | doi-access = free }}</ref>

In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950.<ref name="United Nations Department of Economic and Social Affairs (DESA)-2018">{{cite web|date=16 May 2018|title=68% of the world population projected to live in urban areas by 2050, says UN|work=United Nations Department of Economic and Social Affairs (DESA)|url=https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html|access-date=18 April 2021|language=en-US|archive-date=10 March 2021|archive-url=https://web.archive.org/web/20210310163911/https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html|url-status=live}}</ref> The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population.<ref name="United Nations Department of Economic and Social Affairs (DESA)-2018" /> Problems for humans living in cities include various forms of pollution and crime,<ref>{{cite book |vauthors=Duhart DT |date=October 2000 |title=Urban, Suburban, and Rural Victimization, 1993–98 |publisher=U.S. Department of Justice, Bureau of Justice Statistics |access-date=1 October 2006 |url=https://www.bjs.gov/content/pub/pdf/usrv98.pdf |archive-date=24 February 2013 |archive-url=https://web.archive.org/web/20130224090226/http://bjs.gov/content/pub/pdf/usrv98.pdf |url-status=live}}</ref> especially in inner city and suburban [[Engineering:Slum|slum]]s. Humans have had a dramatic effect on the environment. They are [[Biology:Apex predator|apex predator]]s, being rarely preyed upon by other species.<ref name="pmid24497513">{{cite journal |vauthors=Roopnarine PD |title=Humans are apex predators |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=111 |issue=9 |pages=E796 |date=March 2014 |pmid=24497513 |pmc=3948303 |doi=10.1073/pnas.1323645111 |bibcode=2014PNAS..111E.796R |doi-access=free}}</ref> Human population growth, industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing [[Earth:Holocene extinction|mass extinction]] of other forms of life.<ref name="Stokstad">{{cite web |url=https://www.science.org/content/article/landmark-analysis-documents-alarming-global-decline-nature |title=Landmark analysis documents the alarming global decline of nature |vauthors=Stokstad E |date=5 May 2019 |website=Science |publisher=AAAS |language=en |access-date=9 May 2021 |quote="For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use{{snd}}principally agriculture{{snd}}that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.)" |archive-date=26 October 2021 |archive-url=https://web.archive.org/web/20211026232451/https://www.science.org/content/article/landmark-analysis-documents-alarming-global-decline-nature |url-status=live}}</ref><ref>{{cite journal |vauthors=Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR |date=July 2006 |title=Human impacts on the rates of recent, present, and future bird extinctions |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=103 |issue=29 |pages=10941–10946 |bibcode=2006PNAS..10310941P |doi=10.1073/pnas.0604181103 |pmc=1544153 |pmid=16829570 |doi-access=free}}</ref>

== Biology ==

=== Anatomy and physiology ===
{{Main|Medicine:Human body}}
[[File:Human skeleton front en.svg|thumb|Diagram of the human skeleton]]
Most aspects of human physiology are closely [[Biology:Homology|homologous]] to corresponding aspects of animal physiology. The dental formula of humans is: {{DentalFormula|upper=2.1.2.3|lower=2.1.2.3}}. Humans have proportionately shorter palates and much smaller [[Medicine:Human tooth|teeth]] than other primates. They are the only primates to have short, relatively flush canine teeth. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars, with some individuals having them congenitally absent.<ref name="Revolution">{{cite book| vauthors = Collins D |url=https://archive.org/details/humanrevolutionf0000coll|title=The Human Revolution: From Ape to Artist|year=1976|isbn=978-0-7148-1676-0|page=[https://archive.org/details/humanrevolutionf0000coll/page/208 208]|publisher=Phaidon |url-access=registration}}</ref>

Humans share with chimpanzees a [[Biology:Vestigiality|vestigial]] tail, [[Biology:Appendix (anatomy)|appendix]], flexible shoulder joints, grasping fingers and opposable thumbs.<ref>{{cite book| vauthors = Marks JM |title=Human Biodiversity: Genes, Race, and History|date=2001|publisher=Transaction Publishers|isbn=978-0-202-36656-2|page=16|language=en}}</ref> Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling, [[Physics:Hearing|hearing]] and [[Biology:Digestion#Protein digestion|digesting proteins]].<ref name="O'Neil" /> While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair, most of which is so short and wispy as to be practically invisible.<ref>{{cite news|date=2017|title=How to be Human: The reason we are so scarily hairy|work=New Scientist|url=https://www.newscientist.com/article/mg23631460-700-why-are-humans-so-hairy/|access-date=29 April 2020|archive-date=25 February 2021|archive-url=https://web.archive.org/web/20210225235006/https://www.newscientist.com/article/mg23631460-700-why-are-humans-so-hairy/|url-status=live}}</ref><ref>{{cite journal | vauthors = Sandel AA | title = Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness | journal = American Journal of Physical Anthropology | volume = 152 | issue = 1 | pages = 145–150 | date = September 2013 | pmid = 23900811 | doi = 10.1002/ajpa.22333 | hdl-access = free | hdl = 2027.42/99654 }}</ref> Humans have about 2 million [[Biology:Sweat gland|sweat gland]]s spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.<ref>{{cite web| vauthors = Kirchweger G |title=The Biology of Skin Color: Black and White|url=https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|url-status=live|archive-url=https://web.archive.org/web/20130216070146/https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|archive-date=16 February 2013|access-date=6 January 2013|date=2 February 2001|work=Evolution: Library|publisher=PBS}}</ref>

It is estimated that the worldwide average [[Social:Human height|height for an adult human]] male is about {{Height|cm=171|precision=0}}, while the worldwide average height for adult human females is about {{Height|cm=159|precision=0}}.<ref>{{cite journal|vauthors=Roser M, Appel C, Ritchie H|date=8 October 2013|title=Human Height|url=https://ourworldindata.org/human-height|journal=Our World in Data|access-date=30 July 2022|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130203158/https://ourworldindata.org/human-height|url-status=live}}</ref> Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely [[Biology:Old age|aged]].<ref>{{cite web|title=Senior Citizens Do Shrink – Just One of the Body Changes of Aging|url=https://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|url-status=dead|archive-url=https://web.archive.org/web/20130219004303/https://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|archive-date=19 February 2013|access-date=6 January 2013|work=News|publisher=Senior Journal}}</ref> Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions.<ref>{{cite journal | vauthors = Bogin B, Rios L | title = Rapid morphological change in living humans: implications for modern human origins | journal = Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology | volume = 136 | issue = 1 | pages = 71–84 | date = September 2003 | pmid = 14527631 | doi = 10.1016/S1095-6433(02)00294-5 }}</ref> The average mass of an adult human is {{Convert|59|kg|lb|abbr=on}} for females and {{Convert|77|kg|lb|abbr=on}} for males.<ref>{{cite web|title=Human weight|url=https://www.articleworld.org/index.php/Human_weight|url-status=live|archive-url=https://web.archive.org/web/20111208053451/https://articleworld.org/index.php/Human_weight|archive-date=8 December 2011|access-date=10 December 2011|publisher=Articleworld.org}}</ref><ref>{{cite web | vauthors = Schlessingerman A | date = 2003 |title=Mass Of An Adult|url=https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|url-status=live|archive-url=https://web.archive.org/web/20180101030223/https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|archive-date=1 January 2018|access-date=31 December 2017|publisher=The Physics Factbook: An Encyclopedia of Scientific Essays}}</ref> Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals.<ref>{{cite book|vauthors=Kushner R|url={{GBurl|id=vWjK5etS7PMC|p=121}}|title=Treatment of the Obese Patient (Contemporary Endocrinology)|publisher=Humana Press|year=2007|isbn=978-1-59745-400-1|location=Totowa, NJ|page=158|access-date=5 April 2009}}</ref><ref name="Anes2000">{{cite journal | vauthors = Adams JP, Murphy PG | title = Obesity in anaesthesia and intensive care | journal = British Journal of Anaesthesia | volume = 85 | issue = 1 | pages = 91–108 | date = July 2000 | pmid = 10927998 | doi = 10.1093/bja/85.1.91 | doi-access = free }}</ref>

Humans have a far faster and more accurate throw than other animals.<ref>{{cite journal| vauthors = Lombardo MP, Deaner RO |date=March 2018|title=Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans |journal=The Quarterly Review of Biology|language=en|volume=93|issue=1|pages=1–16|doi=10.1086/696721|s2cid=90757192|issn=0033-5770}}</ref> Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances.<ref>{{cite news |url=https://www.nytimes.com/2009/10/27/health/27well.html |work=The New York Times |title=The Human Body Is Built for Distance | vauthors = Parker-Pope T |date=27 October 2009 |url-status=live |archive-url=https://web.archive.org/web/20151105211812/https://www.nytimes.com/2009/10/27/health/27well.html |archive-date=5 November 2015 }}</ref><ref name="O'Neil">{{cite web | vauthors = O'Neil D |title=Humans |url=https://anthro.palomar.edu/primate/prim_8.htm |work=Primates |publisher=Palomar College |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130111004211/https://anthro.palomar.edu/primate/prim_8.htm |archive-date=11 January 2013 }}</ref> Humans' thinner body hair and more productive sweat glands help avoid [[Medicine:Heat exhaustion|heat exhaustion]] while running for long distances.<ref>{{cite web | vauthors = John B |title=What is the role of sweating glands in balancing body temperature when running a marathon? |url=https://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |publisher=Livestrong.com |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130131184339/https://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |archive-date=31 January 2013 }}</ref>

=== Genetics ===

Like most animals, humans are a [[Biology:Ploidy|diploid]] and [[Biology:Eukaryote|eukaryotic]] species. Each [[Biology:Somatic cell|somatic cell]] has two sets of 23 [[Biology:Chromosome|chromosome]]s, each set received from one parent; [[Biology:Gamete|gamete]]s have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of [[Biology:Autosome|autosome]]s and one pair of [[Biology:Sex-determination system|sex chromosomes]]. Like other mammals, humans have an [[Biology:XY sex-determination system|XY sex-determination system]], so that females have the sex chromosomes XX and males have XY.<ref name="Therman1980">{{cite book | vauthors = Therman E |title=Human Chromosomes: Structure, Behavior, Effects |date=1980 |publisher=[[Company:Springer Science+Business Media|Springer US]] |pages=112–124 |isbn=978-1-4684-0109-7 |doi=10.1007/978-1-4684-0107-3|s2cid=36686283 }}</ref> [[Biology:Gene|Gene]]s and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood.<ref>{{cite journal | vauthors = Edwards JH, Dent T, Kahn J | title = Monozygotic twins of different sex | journal = Journal of Medical Genetics | volume = 3 | issue = 2 | pages = 117–123 | date = June 1966 | pmid = 6007033 | pmc = 1012913 | doi = 10.1136/jmg.3.2.117 }}</ref><ref>{{cite journal | vauthors = Machin GA | title = Some causes of genotypic and phenotypic discordance in monozygotic twin pairs | journal = American Journal of Medical Genetics | volume = 61 | issue = 3 | pages = 216–228 | date = January 1996 | pmid = 8741866 | doi = 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S }}</ref>

While no humans{{snd}}not even monozygotic twins{{snd}}are genetically identical,<ref>{{cite journal | vauthors = Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, Zink F, Helgason EA, Jonsdottir I, Gylfason A, Jonasdottir A, Jonasdottir A, Beyter D, Steingrimsdottir T, Norddahl GL, Magnusson OT, Masson G, Halldorsson BV, Thorsteinsdottir U, Helgason A, Sulem P, Gudbjartsson DF, Stefansson K | display-authors = 6 | title = Differences between germline genomes of monozygotic twins | journal = Nature Genetics | volume = 53 | issue = 1 | pages = 27–34 | date = January 2021 | pmid = 33414551 | doi = 10.1038/s41588-020-00755-1 | s2cid = 230986741 }}</ref> two humans on average will have a genetic similarity of 99.5%-99.9%.<ref>{{cite web|title=Genetic – Understanding Human Genetic Variation|url=https://science.education.nih.gov/supplements/nih1/genetic/guide/genetic_variation1.htm|url-status=dead|archive-url=https://web.archive.org/web/20130825143543/https://science.education.nih.gov/supplements/nih1/genetic/guide/genetic_variation1.htm|archive-date=25 August 2013|access-date=13 December 2013|work=Human Genetic Variation|publisher=National Institute of Health (NIH)|quote=Between any two humans, the amount of genetic variation{{snd}}biochemical individuality{{snd}}is about 0.1%.}}</ref><ref>{{cite journal | vauthors = Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, Axelrod N, Huang J, Kirkness EF, Denisov G, Lin Y, MacDonald JR, Pang AW, Shago M, Stockwell TB, Tsiamouri A, Bafna V, Bansal V, Kravitz SA, Busam DA, Beeson KY, McIntosh TC, Remington KA, Abril JF, Gill J, Borman J, Rogers YH, Frazier ME, Scherer SW, Strausberg RL, Venter JC | display-authors = 6 | title = The diploid genome sequence of an individual human | journal = PLOS Biology | volume = 5 | issue = 10 | pages = e254 | date = September 2007 | pmid = 17803354 | pmc = 1964779 | doi = 10.1371/journal.pbio.0050254 | doi-access = free }}</ref> This makes them more [[Biology:Human genetic variation|homogeneous]] than other great apes, including chimpanzees.<ref name="REGWG2005">{{cite journal | vauthors = ((Race, Ethnicity, and Genetics Working Group)) | title = The use of racial, ethnic, and ancestral categories in human genetics research | journal = American Journal of Human Genetics | volume = 77 | issue = 4 | pages = 519–532 | date = October 2005 | pmid = 16175499 | pmc = 1275602 | doi = 10.1086/491747 }}</ref><ref name="oxf">{{cite web|title=Chimps show much greater genetic diversity than humans|url=https://www.ox.ac.uk/media/news_stories/2012/120302.html|url-status=dead|archive-url=https://web.archive.org/web/20131218091207/https://www.ox.ac.uk/media/news_stories/2012/120302.html|archive-date=18 December 2013|access-date=13 December 2013|work=Media|publisher=University of Oxford}}</ref> This small variation in human DNA compared to many other species suggests a [[Biology:Population bottleneck|population bottleneck]] during the [[Earth:Late Pleistocene|Late Pleistocene]] (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs.<ref name="Harpending1998">{{cite journal | vauthors = Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST | title = Genetic traces of ancient demography | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 95 | issue = 4 | pages = 1961–1967 | date = February 1998 | pmid = 9465125 | pmc = 19224 | doi = 10.1073/pnas.95.4.1961 | bibcode = 1998PNAS...95.1961H | doi-access = free }}</ref><ref name="Jorde1997">{{cite journal | vauthors = Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, Kere J, Harpending HC | display-authors = 6 | title = Microsatellite diversity and the demographic history of modern humans | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 94 | issue = 7 | pages = 3100–3103 | date = April 1997 | pmid = 9096352 | pmc = 20328 | doi = 10.1073/pnas.94.7.3100 | bibcode = 1997PNAS...94.3100J | doi-access = free }}</ref> The forces of [[Biology:Natural selection|natural selection]] have continued to operate on human populations, with evidence that certain regions of the [[Biology:Genome|genome]] display [[Biology:Directional selection|directional selection]] in the past 15,000 years.<ref name="urlNYT">{{cite news| vauthors = Wade N |date=7 March 2007|title=Still Evolving, Human Genes Tell New Story|newspaper=The New York Times|url=https://www.nytimes.com/2006/03/07/science/07evolve.html|url-status=live|access-date=13 February 2012|archive-url=https://web.archive.org/web/20120114232231/https://www.nytimes.com/2006/03/07/science/07evolve.html|archive-date=14 January 2012}}</ref>

The [[Biology:Human genome|human genome]] was first sequenced in 2001<ref>{{cite journal | vauthors = Pennisi E |  title = The human genome | journal = Science | volume = 291 | issue = 5507 | pages = 1177–1180 | date = February 2001 | pmid = 11233420 | doi = 10.1126/science.291.5507.1177 | s2cid = 38355565 }}</ref> and by 2020 hundreds of thousands of genomes had been sequenced.<ref>{{cite journal | vauthors = Rotimi CN, Adeyemo AA | title = From one human genome to a complex tapestry of ancestry | journal = Nature | volume = 590 | issue = 7845 | pages = 220–221 | date = February 2021 | pmid = 33568827 | doi = 10.1038/d41586-021-00237-2 | bibcode = 2021Natur.590..220R | s2cid = 231882262 }}</ref> In 2012 the [[International HapMap Project]] had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms.<ref>{{cite journal | vauthors = Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, Dermitzakis E, Schaffner SF, Yu F, Peltonen L, Dermitzakis E, Bonnen PE, Altshuler DM, Gibbs RA, de Bakker PI, Deloukas P, Gabriel SB, Gwilliam R, Hunt S, Inouye M, Jia X, Palotie A, Parkin M, Whittaker P, Yu F, Chang K, Hawes A, Lewis LR, Ren Y, Wheeler D, Gibbs RA, Muzny DM, Barnes C, Darvishi K, Hurles M, Korn JM, Kristiansson K, Lee C, McCarrol SA, Nemesh J, Dermitzakis E, Keinan A, Montgomery SB, Pollack S, Price AL, Soranzo N, Bonnen PE, Gibbs RA, Gonzaga-Jauregui C, Keinan A, Price AL, Yu F, Anttila V, Brodeur W, Daly MJ, Leslie S, McVean G, Moutsianas L, Nguyen H, Schaffner SF, Zhang Q, Ghori MJ, McGinnis R, McLaren W, Pollack S, Price AL, Schaffner SF, Takeuchi F, Grossman SR, Shlyakhter I, Hostetter EB, Sabeti PC, Adebamowo CA, Foster MW, Gordon DR, Licinio J, Manca MC, Marshall PA, Matsuda I, Ngare D, Wang VO, Reddy D, Rotimi CN, Royal CD, Sharp RR, Zeng C, Brooks LD, McEwen JE | display-authors = 6 | title = Integrating common and rare genetic variation in diverse human populations | journal = Nature | volume = 467 | issue = 7311 | pages = 52–58 | date = September 2010 | pmid = 20811451 | doi = 10.1038/nature09298 | pmc = 3173859 | bibcode = 2010Natur.467...52T }}</ref> African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially [[Earth:Oceania|Oceania]] and the Americas.<ref name="Bergstrom2020" /> By 2010 estimates, humans have approximately 22,000 genes.<ref name=Pertea2010>{{cite journal | vauthors = Pertea M, Salzberg SL | title = Between a chicken and a grape: estimating the number of human genes | journal = Genome Biology | volume = 11 | issue = 5 | page = 206 | year = 2010 | pmid = 20441615 | pmc = 2898077 | doi = 10.1186/gb-2010-11-5-206 | doi-access = free }}</ref> By comparing mitochondrial DNA, which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose [[Biology:Genetic marker|genetic marker]] is found in all modern humans, the so-called [[Biology:Mitochondrial Eve|mitochondrial Eve]], must have lived around 90,000 to 200,000 years ago.<ref name="pmid3025745">{{cite journal | vauthors = Cann RL, Stoneking M, Wilson AC | title = Mitochondrial DNA and human evolution | journal = Nature | volume = 325 | issue = 6099 | pages = 31–36 | year = 1987 | pmid = 3025745 | doi = 10.1038/325031a0 | bibcode = 1987Natur.325...31C | s2cid = 4285418 }}</ref><ref>{{cite journal | vauthors = Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, Salas A, Oppenheimer S, Macaulay V, Richards MB | display-authors = 6 | title = Correcting for purifying selection: an improved human mitochondrial molecular clock | journal = American Journal of Human Genetics | volume = 84 | issue = 6 | pages = 740–759 | date = June 2009 | pmid = 19500773 | pmc = 2694979 | doi = 10.1016/j.ajhg.2009.05.001}}</ref><ref>{{Cite web|url=https://www.leeds.ac.uk/news/article/245/new_molecular_clock_aids_dating_of_human_migration_history|title=University of Leeds &#124; News > Technology > New 'molecular clock' aids dating of human migration history|date=20 August 2017|archive-url=https://web.archive.org/web/20170820230218/https://www.leeds.ac.uk/news/article/245/new_molecular_clock_aids_dating_of_human_migration_history|archive-date=20 August 2017}}</ref><ref name="poz">{{cite journal | vauthors = Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, Snyder M, Quintana-Murci L, Kidd JM, Underhill PA, Bustamante CD | display-authors = 6 | title = Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females | journal = Science | volume = 341 | issue = 6145 | pages = 562–565 | date = August 2013 | pmid = 23908239 | pmc = 4032117 | doi = 10.1126/science.1237619 | bibcode = 2013Sci...341..562P }}</ref>

=== Life cycle ===

[[File:Tubal Pregnancy with embryo.jpg|thumb|A 10&nbsp;mm human embryo at 5 weeks]]
Most human reproduction takes place by internal fertilization via sexual intercourse, but can also occur through [[Engineering:Assisted reproductive technology|assisted reproductive technology]] procedures.<ref name="She2016">{{cite book| vauthors = Shehan CL |url={{GBurl|id=-gSeCAAAQBAJ|p=406}}|title=The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set|date=2016|publisher=John Wiley & Sons|isbn=978-0-470-65845-1|page=406|name-list-style=vanc}}</ref> The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days.<ref>{{cite journal | vauthors = Jukic AM, Baird DD, [[Biography:Clarice Weinberg|Weinberg CR]], McConnaughey DR, Wilcox AJ | title = Length of human pregnancy and contributors to its natural variation | journal = Human Reproduction | volume = 28 | issue = 10 | pages = 2848–2855 | date = October 2013 | pmid = 23922246 | pmc = 3777570 | doi = 10.1093/humrep/det297 }}</ref> Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a [[Biology:Fetus|fetus]].<ref name="nursing">{{cite book | vauthors = Klossner NJ | url = {{GBurl|id=B47OVg25g-QC|q=fetal stage begins|p=103}} | title = Introductory Maternity Nursing | date = 2005 | page = 103 | publisher=Lippincott Williams & Wilkins | quote = The fetal stage is from the beginning of the 9th week after fertilization and continues until birth | isbn = 978-0-7817-6237-3 | access-date = 30 July 2022 }}</ref> Humans are able to [[Medicine:Labor induction|induce early labor]] or perform a [[Medicine:Caesarean section|caesarean section]] if the child needs to be born earlier for medical reasons.<ref name="WHO2014">{{cite web|author=World Health Organization|date=November 2014|title=Preterm birth Fact sheet N°363|url=https://www.who.int/mediacentre/factsheets/fs363/en/|url-status=live|archive-url=https://web.archive.org/web/20150307050438/https://www.who.int/mediacentre/factsheets/fs363/en/|archive-date=7 March 2015|access-date=6 March 2015|work=who.int}}</ref> In developed countries, infants are typically {{Convert|3|-|4|kg|lb|abbr=on|lk=off|0}} in weight and {{Convert|47|-|53|cm|in|abbr=on|lk=off|0}} in height at birth.<ref>{{cite journal | vauthors = Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD | title = The World Health Organization fetal growth charts: concept, findings, interpretation, and application | journal = American Journal of Obstetrics and Gynecology | volume = 218 | issue = 2S | pages = S619–S629 | date = February 2018 | pmid = 29422204 | doi = 10.1016/j.ajog.2017.12.010 | s2cid = 46810955 | doi-access = free }}</ref><ref>{{cite web|date=18 March 2019|title=What is the average baby length? Growth chart by month|url=https://www.medicalnewstoday.com/articles/324728|access-date=18 April 2021|website=www.medicalnewstoday.com|language=en|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127193402/https://www.medicalnewstoday.com/articles/324728|url-status=live}}</ref> However, [[Medicine:Low birth weight|low birth weight]] is common in developing countries, and contributes to the high levels of infant mortality in these regions.<ref name="Khor2003">{{cite journal | vauthors = Khor GL | title = Update on the prevalence of malnutrition among children in Asia | journal = Nepal Medical College Journal | volume = 5 | issue = 2 | pages = 113–122 | date = December 2003 | pmid = 15024783 }}</ref>

Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death.<ref>{{cite journal| vauthors = Rosenberg KR |date=1992|title=The evolution of modern human childbirth |journal=American Journal of Physical Anthropology|language=en|volume=35|issue=S15|pages=89–124|doi=10.1002/ajpa.1330350605|issn=1096-8644}}</ref> The size of the fetus's head is more closely matched to the [[Biology:Pelvis|pelvis]] than in other primates.<ref name="Pavlicev">{{cite journal | vauthors = Pavličev M, Romero R, Mitteroecker P | title = Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma | journal = American Journal of Obstetrics and Gynecology | volume = 222 | issue = 1 | pages = 3–16 | date = January 2020 | pmid = 31251927 | doi = 10.1016/j.ajog.2019.06.043 | pmc = 9069416 | s2cid = 195761874 }}</ref> The reason for this is not completely understood,{{#tag:ref|Traditionally this has been explained by conflicting [[Biology:Evolutionary pressure|evolutionary pressure]]s involved in bipedalism and encephalization (called the [[Biology:Obstetrical dilemma|obstetrical dilemma]]), but recent research suggest it might be more complicated than that.<ref name="Pavlicev" /><ref>{{cite news|title=The real reasons why childbirth is so painful and dangerous| vauthors = Barras C |date=22 December 2016|publisher=BBC}}</ref>|group=n}} but it contributes to a painful labor that can last 24 hours or more.<ref>{{cite web | vauthors = Kantrowitz B | date = 2 July 2007 | title = What Kills One Woman Every Minute of Every Day? | work = Newsweek | url = https://www.msnbc.msn.com/id/19389326/site/newsweek/ | archive-url = https://web.archive.org/web/20070628160443/https://www.msnbc.msn.com/id/19389326/site/newsweek/ | archive-date = 28 June 2007 | quote = A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in [[Place:Sub-Saharan Africa|sub-Saharan Africa]], compared to 1 in 2,800 in developed countries. }}</ref> The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries.<ref name="Rush2000">{{cite journal | vauthors = Rush D | title = Nutrition and maternal mortality in the developing world | journal = The American Journal of Clinical Nutrition | volume = 72 | issue = 1 Suppl | pages = 212S–240S | date = July 2000 | pmid = 10871588 | doi = 10.1093/ajcn/72.1.212S | doi-access = free }}</ref>

Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother.<ref>{{cite book|vauthors=Laland KN, Brown G|url={{GBurl|id=2KcbFVBSxWYC}}|title=Sense and Nonsense: Evolutionary Perspectives on Human Behaviour|date=2011|publisher=Oxford University Press|isbn=978-0-19-958696-7|page=7|language=en|access-date=30 July 2022}}</ref> Helpless at birth, humans continue to grow for some years, typically reaching [[Biology:Sexual maturity|sexual maturity]] at 15 to 17 years of age.<ref name="Kail">{{cite book|vauthors=Kail RV, Cavanaugh JC|url={{GBurl|id=E-n5E7oyCgoC|p=296}}|title=Human Development: A Lifespan View|publisher=Cengage Learning|year=2010|isbn=978-0-495-60037-4|edition=5th|page=296|access-date=30 July 2022}}</ref><ref name="Schuiling">{{cite book|vauthors=Schuiling KD, Likis FE|url={{GBurl|id=QTDFDAAAQBAJ|p=22}}|title=Women's Gynecologic Health|publisher=Jones & Bartlett Learning|year=2016|isbn=978-1-284-12501-6|page=22|quote=The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13.|access-date=30 July 2022}}</ref><ref name="Phillips">{{cite book|vauthors=Phillips DC|url={{GBurl|id=84StBAAAQBAJ|p=18}}|title=Encyclopedia of Educational Theory and Philosophy|publisher=SAGE Publications|year=2014|isbn=978-1-4833-6475-9|pages=18–19|quote=On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average).|access-date=30 July 2022}}</ref> The human life span has been split into various stages ranging from three to twelve. Common stages include infancy, childhood, [[Social:Adolescence|adolescence]], [[Biology:Adult|adult]]hood and [[Biology:Old age|old age]].<ref>{{cite journal| vauthors = Mintz S |date=1993|title=Life stages|journal=Encyclopedia of American Social History|volume=3|pages=7–33}}</ref> The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence.<ref>{{cite journal | vauthors = Soliman A, De Sanctis V, Elalaily R, Bedair S | title = Advances in pubertal growth and factors influencing it: Can we increase pubertal growth? | journal = Indian Journal of Endocrinology and Metabolism | volume = 18 | issue = Suppl 1 | pages = S53-62 | date = November 2014 | pmid = 25538878 | pmc = 4266869 | doi = 10.4103/2230-8210.145075 | doi-access = free }}</ref> Human females undergo [[Medicine:Menopause|menopause]] and become [[Medicine:Infertility|infertile]] at around the age of 50.<ref>{{cite journal | vauthors = Walker ML, Herndon JG | title = Menopause in nonhuman primates? | journal = Biology of Reproduction | volume = 79 | issue = 3 | pages = 398–406 | date = September 2008 | pmid = 18495681 | pmc = 2553520 | doi = 10.1095/biolreprod.108.068536 }}</ref> It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the [[Biology:Grandmother hypothesis|grandmother hypothesis]]), rather than by continuing to bear children into old age.<ref name="Diamond1997">{{cite book | vauthors = Diamond J |title=Why is Sex Fun? The Evolution of Human Sexuality |publisher=Basic Books |location=New York|year=1997 |pages=167–170 |isbn=978-0-465-03127-6}}</ref><ref name="Peccei2001">{{cite journal | vauthors = Peccei JS |title= Menopause: Adaptation or epiphenomenon? |journal=Evolutionary Anthropology |volume=10 |issue=2 |year=2001 |pages=43–57 |doi=10.1002/evan.1013|s2cid=1665503 }}</ref>

The life span of an individual depends on two major factors, genetics and lifestyle choices.<ref name="USC">{{cite news | vauthors = Marziali C |date=7 December 2010 |title=Reaching Toward the Fountain of Youth |url=https://uscnews.usc.edu/health/reaching_toward_the_fountain_of_youth.html|archive-url=https://web.archive.org/web/20101213203112/https://uscnews.usc.edu/health/reaching_toward_the_fountain_of_youth.html|url-status=dead|archive-date=13 December 2010 |work=USC Trojan Family Magazine |access-date=7 December 2010}}</ref> For various reasons, including biological/genetic causes, women live on average about four years longer than men.<ref>{{cite web | vauthors = Kalben BB |title=Why Men Die Younger: Causes of Mortality Differences by Sex |publisher=Society of Actuaries |year=2002 |url=https://www.soa.org/news-and-publications/publications/other-publications/monographs/m-li01-1-toc.aspx |url-status=live |archive-url=https://web.archive.org/web/20130701185241/https://www.soa.org/news-and-publications/publications/other-publications/monographs/m-li01-1-toc.aspx |archive-date=1 July 2013 }}</ref> {{as of|2018|}}, the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy.<ref>{{cite web|date=2018|title=Life expectancy at birth, female (years)|url=https://data.worldbank.org/indicator/SP.DYN.LE00.FE.IN|access-date=13 October 2020|website=World Bank|archive-date=24 January 2021|archive-url=https://web.archive.org/web/20210124203646/https://data.worldbank.org/indicator/SP.DYN.LE00.FE.IN|url-status=live}}</ref><ref>{{cite web|date=2018|title=Life expectancy at birth, male (years)|url=https://data.worldbank.org/indicator/SP.DYN.LE00.MA.IN|access-date=13 October 2020|website=World Bank|archive-date=24 February 2021|archive-url=https://web.archive.org/web/20210224133034/https://data.worldbank.org/indicator/SP.DYN.LE00.MA.IN|url-status=live}}</ref> There are significant geographical variations in human life expectancy, mostly correlated with economic development{{snd}}for example, life expectancy at birth in [[Place:Hong Kong|Hong Kong]] is 87.6&nbsp;years for girls and 81.8 for boys, while in the Central African Republic, it is 55.0&nbsp;years for girls and 50.6 for boys.<ref>{{cite book | vauthors = Conceição P, etal | title = Human Development Report | date = 2019 | publisher = United Nations Development Programme | url = https://hdr.undp.org/sites/default/files/hdr2019.pdf | isbn = 978-92-1-126439-5 | access-date = 30 July 2022 | archive-date = 20 March 2021 | archive-url = https://web.archive.org/web/20210320094952/http://hdr.undp.org/sites/default/files/hdr2019.pdf | url-status = live }}</ref><ref name="MLT">{{cite web|url=https://hdr.undp.org/sites/all/themes/hdr_theme/country-notes/MLT.pdf|title=Human Development Report 2019|language=en|publisher=[[Organization:United Nations Development Programme|United Nations Development Programme]]|access-date=30 July 2022|archive-date=22 April 2022|archive-url=https://web.archive.org/web/20220422102059/https://hdr.undp.org/sites/all/themes/hdr_theme/country-notes/MLT.pdf|url-status=dead}}</ref> The developed world is generally aging, with the median age around 40 years. In the developing world, the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older.<ref>{{cite web | url = https://www.cia.gov/library/publications/the-world-factbook/ | title = The World Factbook | archive-url = https://web.archive.org/web/20090912045414/https://www.cia.gov/library/publications/the-world-factbook/ | archive-date = 12 September 2009 | publisher = U.S. Central Intelligence Agency | access-date = 2 April 2005 }}</ref> In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide.<ref name="WORLD2012">{{cite web|url=http://www.unfpa.org/webdav/site/global/shared/documents/publications/2012/UNFPA-Report-Chapter1.pdf|title=Chapter 1: Setting the Scene|year=2012|publisher=UNFPA|access-date=11 January 2013|archive-url=https://web.archive.org/web/20130612052543/http://www.unfpa.org/webdav/site/global/shared/documents/publications/2012/UNFPA-Report-Chapter1.pdf|archive-date=12 June 2013}}</ref>
{| class="wikitable" style="width: 80%; margin-left: auto; margin-right: auto; border: none;"
|+
! colspan="5" | Human life stages
|-
|[[File:Redheaded child mesmerized 2.jpg|100px|center]]
|[[File:Ромський хлопчик (Мукачево).jpg|100px|center]]
|[[File:Boy in Dar es Salaam (14453809622).jpg|100px|center]]
|[[File:Pataxo001.jpg|100px|center]]
|[[File:An old age.JPG|100px|center]]
|-
|[[File:Baby playing with yellow paint. Work by Dutch artist Peter Klashorst entitled "Experimental".jpg|100px|center]]
|[[File:Ethnie dong 6511a.jpg|100px|center]]
|[[File:Portrait of a Persian lady in Iran, 10-08-2006 (cropped).jpg|100px|center]]
|[[File:Punjabi woman smile.jpg|100px|center]]
|[[File:HappyPensioneer.jpg|100px|center]]
|- style="text-align: center;"
|style="width: 20%"|Infant boy and girl
|style="width: 20%"|Boy and girl before puberty (children)
|style="width: 20%"|Adolescent male and female
|style="width: 20%"|[[Biology:Adult|Adult]] man and woman
|style="width: 20%"|Elderly man and woman
|}

=== Diet ===
{{Main|Medicine:Human nutrition}}
[[File:Preparing The Feast.jpg|thumb|right|Humans living in [[Place:Bali|Bali]], Indonesia, preparing a meal]]Humans are omnivorous, capable of consuming a wide variety of plant and animal material.<ref>{{cite journal | vauthors = Haenel H | title = Phylogenesis and nutrition | journal = Die Nahrung | volume = 33 | issue = 9 | pages = 867–887 | year = 1989 | pmid = 2697806 }}</ref><ref>{{cite book | veditors = Ungar PS |year=2007 | vauthors = Cordain L |title=Evolution of the human diet: the known, the unknown and the unknowable |chapter=Implications of Plio-pleistocene diets for modern humans |quote=Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. |pages=264–265}}</ref> Human groups have adopted a range of diets from purely vegan to primarily carnivorous. In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources.<ref>{{cite journal | title = Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets | journal = Journal of the American Dietetic Association | volume = 103 | issue = 6 | pages = 748–765 | date = June 2003 | pmid = 12778049 | doi = 10.1053/jada.2003.50142 | author1 = American Dietetic Association }}</ref> The human diet is prominently reflected in human culture and has led to the development of [[Engineering:Food science|food science]].<ref name="Crittenden-2017">{{cite journal| vauthors = Crittenden AN, Schnorr SL |date=2017|title=Current views on hunter-gatherer nutrition and the evolution of the human diet |journal=American Journal of Physical Anthropology |volume=162 |issue=S63 |pages=84–109 |doi=10.1002/ajpa.23148 |pmid=28105723|doi-access=free }}</ref>

Until the development of agriculture, ''Homo sapiens'' employed a hunter-gatherer method as their sole means of food collection.<ref name="Crittenden-2017" /> This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game, which must be hunted and captured in order to be consumed.<ref>{{cite journal | vauthors = Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, O'Keefe JH, Brand-Miller J | display-authors = 6 | title = Origins and evolution of the Western diet: health implications for the 21st century | journal = The American Journal of Clinical Nutrition | volume = 81 | issue = 2 | pages = 341–354 | date = February 2005 | pmid = 15699220 | doi = 10.1093/ajcn.81.2.341 | name-list-style = vanc | doi-access = free }}</ref> It has been proposed that humans have used fire to prepare and cook food since the time of ''[[Biology:Homo erectus|Homo erectus]]''.<ref>{{cite journal | vauthors = Ulijaszek SJ | title = Human eating behaviour in an evolutionary ecological context | journal = The Proceedings of the Nutrition Society | volume = 61 | issue = 4 | pages = 517–526 | date = November 2002 | pmid = 12691181 | doi = 10.1079/PNS2002180 | doi-access = free }}</ref> Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture,<ref>{{cite journal|title=Unearthing the origins of agriculture|author=John Carey|doi=10.1073/pnas.2304407120|journal=Proceedings of the National Academy of Sciences|volume=120|issue=15|date=2023|doi-access=free|pmc=10104519}}</ref> a gradual process called the [[History:Neolithic Revolution|Neolithic Revolution]].<ref>{{cite journal|title=Can models of evolutionary transition clarify the debates over the Neolithic Revolution?|url=https://royalsocietypublishing.org/doi/full/10.1098/rstb.2021.0413|author1=Ayelet Shavit|author2=Gonen Sharon|journal=[[Organization:Philosophical Transactions of the Royal Society B|Philosophical Transactions of the Royal Society B]]|date=2023|volume=378|issue=1872}}}</ref> These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest [[Chemistry:Lactose|lactose]] in some adults.<ref>{{cite journal | vauthors = Krebs JR | title = The gourmet ape: evolution and human food preferences | journal = The American Journal of Clinical Nutrition | volume = 90 | issue = 3 | pages = 707S–711S | date = September 2009 | pmid = 19656837 | doi = 10.3945/ajcn.2009.27462B | doi-access = free }}</ref><ref>{{cite journal | vauthors = Holden C, Mace R | title = Phylogenetic analysis of the evolution of lactose digestion in adults | journal = Human Biology | volume = 69 | issue = 5 | pages = 605–628 | date = October 1997 | pmid = 9299882 }}</ref> The types of food consumed, and how they are prepared, have varied widely by time, location, and culture.<ref>{{cite web|vauthors=Gibbons A|title=The Evolution of Diet|url=https://www.nationalgeographic.com/foodfeatures/evolution-of-diet/|access-date=18 April 2021|website=National Geographic|archive-date=18 August 2014|archive-url=https://web.archive.org/web/20140818204010/https://www.nationalgeographic.com/foodfeatures/evolution-of-diet/|url-status=live}}</ref><ref>{{cite journal|vauthors=Ritchie H, Roser M|date=20 August 2017|title=Diet Compositions|url=https://ourworldindata.org/diet-compositions|journal=Our World in Data|access-date=30 July 2022|archive-date=25 August 2021|archive-url=https://web.archive.org/web/20210825210934/https://ourworldindata.org/diet-compositions|url-status=live}}</ref>

In general, humans can survive for up to eight weeks without food, depending on stored body fat.<ref>{{cite web|vauthors=Lieberson AD|date=2004|title=How Long Can a Person Survive without Food?|url=https://www.scientificamerican.com/article/how-long-can-a-person-survive-without-food/|access-date=18 April 2021|website=Scientific American|language=en|archive-date=14 February 2019|archive-url=https://web.archive.org/web/20190214012729/https://www.scientificamerican.com/article/how-long-can-a-person-survive-without-food/|url-status=live}}</ref> Survival without water is usually limited to three or four days, with a maximum of one week.<ref>{{cite web|vauthors=Spector D|date=9 March 2018|title=Here's how many days a person can survive without water|url=https://www.businessinsider.com.au/how-many-days-can-you-survive-without-water-2014-5|access-date=18 April 2021|website=Business Insider Australia|language=en|archive-date=26 June 2014|archive-url=https://web.archive.org/web/20140626030756/https://www.businessinsider.com.au/how-many-days-can-you-survive-without-water-2014-5|url-status=live}}</ref> In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to [[Medicine:Starvation|starvation]].<ref>{{cite web|vauthors=Holmes J|title=Losing 25,000 to Hunger Every Day|url=https://www.un.org/en/chronicle/article/losing-25000-hunger-every-day|access-date=18 April 2021|website=United Nations|language=en|archive-date=27 May 2020|archive-url=https://web.archive.org/web/20200527235650/https://www.un.org/en/chronicle/article/losing-25000-hunger-every-day|url-status=live}}</ref><ref>{{cite web|vauthors=Mai HJ|date=2020|title=U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic|url=https://www.npr.org/sections/coronavirus-live-updates/2020/05/05/850470436/u-n-warns-number-of-people-starving-to-death-could-double-amid-pandemic|access-date=18 April 2021|website=NPR |language=en|archive-date=28 June 2021|archive-url=https://web.archive.org/web/20210628090826/https://www.npr.org/sections/coronavirus-live-updates/2020/05/05/850470436/u-n-warns-number-of-people-starving-to-death-could-double-amid-pandemic|url-status=live}}</ref> Childhood malnutrition is also common and contributes to the [[Medicine:Disease burden|global burden of disease]].<ref>{{cite journal | vauthors = Murray CJ, Lopez AD | title = Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study | journal = Lancet | volume = 349 | issue = 9063 | pages = 1436–1442 | date = May 1997 | pmid = 9164317 | doi = 10.1016/S0140-6736(96)07495-8 | s2cid = 2569153 }}</ref> However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some [[Finance:Developed country|developed]] and a few developing countries. Worldwide, over one billion people are obese,<ref name=Haslam>{{cite journal | vauthors = Haslam DW, James WP | title = Obesity | journal = Lancet | volume = 366 | issue = 9492 | pages = 1197–1209 | date = October 2005 | pmid = 16198769 | doi = 10.1016/S0140-6736(05)67483-1 | s2cid = 208791491 }}</ref> while in the United States 35% of people are obese, leading to this being described as an "[[Medicine:Epidemiology of obesity|obesity epidemic]]."<ref name=Catenacci>{{cite journal | vauthors = Catenacci VA, Hill JO, Wyatt HR | title = The obesity epidemic | journal = Clinics in Chest Medicine | volume = 30 | issue = 3 | pages = 415–444, vii | date = September 2009 | pmid = 19700042 | doi = 10.1016/j.ccm.2009.05.001 }}</ref> Obesity is caused by consuming more [[Calorie|calorie]]s than are expended, so excessive weight gain is usually caused by an energy-dense diet.<ref name=Haslam />

=== Biological variation ===
{{Main|Biology:Human genetic variation}}

[[File:Genetic Variation.jpg|upright=1.3|thumb|Changes in the number and order of genes (A–D) create genetic diversity within and between population.]]
There is biological variation in the human species{{snd}}with traits such as [[Biology:Blood type|blood type]], genetic diseases, cranial features, facial features, organ systems, [[Biology:Eye color|eye color]], hair color and texture, [[Social:Human height|height]] and [[Social:Body shape|build]], and skin color varying across the globe. The typical height of an adult human is between {{Convert|1.4|and|1.9|m|ftin|abbr=on}}, although this varies significantly depending on sex, [[Social:Ethnic origin|ethnic origin]], and family bloodlines.<ref>{{cite journal | vauthors = de Beer H | title = Observations on the history of Dutch physical stature from the late-Middle Ages to the present | journal = Economics and Human Biology | volume = 2 | issue = 1 | pages = 45–55 | date = March 2004 | pmid = 15463992 | doi = 10.1016/j.ehb.2003.11.001 }}</ref><ref name="adapt2">{{cite web | vauthors = O'Neil D |title=Adapting to Climate Extremes |url=https://anthro.palomar.edu/adapt/adapt_2.htm |work=Human Biological Adaptability |publisher=Palomar College |access-date=6 January 2013 |url-status=live |archive-url= https://web.archive.org/web/20130106211840/https://anthro.palomar.edu/adapt/adapt_2.htm |archive-date=6 January 2013 }}</ref> Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet, exercise, and sleep patterns.<ref>{{cite journal | vauthors = Rask-Andersen M, Karlsson T, Ek WE, Johansson Å | title = Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status | journal = PLOS Genetics | volume = 13 | issue = 9 | pages = e1006977 | date = September 2017 | pmid = 28873402 | pmc = 5600404 | doi = 10.1371/journal.pgen.1006977 | doi-access = free }}</ref>

There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk.<ref>{{cite journal | vauthors = Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, Chamberlain AT, Nunes TP, Metodiev S, Ferrand N, Erhardt G | display-authors = 6 | title = Gene-culture coevolution between cattle milk protein genes and human lactase genes | journal = Nature Genetics | volume = 35 | issue = 4 | pages = 311–313 | date = December 2003 | pmid = 14634648 | doi = 10.1038/ng1263 | s2cid = 20415396 }}</ref> Sickle cell anemia, which may provide increased resistance to [[Medicine:Malaria|malaria]], is frequent in populations where [[Medicine:Malaria|malaria]] is endemic.<ref name="Hedrick 2011">{{cite journal | vauthors = Hedrick PW | title = Population genetics of malaria resistance in humans | journal = Heredity | volume = 107 | issue = 4 | pages = 283–304 | date = October 2011 | pmid = 21427751 | pmc = 3182497 | doi = 10.1038/hdy.2011.16 }}</ref><ref name="Weatherall 2008">{{cite journal | vauthors = Weatherall DJ | title = Genetic variation and susceptibility to infection: the red cell and malaria | journal = British Journal of Haematology | volume = 141 | issue = 3 | pages = 276–286 | date = May 2008 | pmid = 18410566 | doi = 10.1111/j.1365-2141.2008.07085.x | s2cid = 28191911 | doi-access = free }}</ref> Populations that have for a very long time inhabited specific climates tend to have developed specific [[Biology:Phenotype|phenotype]]s that are beneficial for those environments{{snd}}[[Biology:Allen's rule|short stature and stocky build in cold regions]], tall and lanky in hot regions, and with high lung capacities or other [[Biology:High-altitude adaptation in humans|adaptations at high altitudes]].<ref>{{cite journal| vauthors = Shelomi M, Zeuss D |date=5 April 2017|title=Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea |journal=Frontiers in Ecology and Evolution|volume=5|doi=10.3389/fevo.2017.00025|s2cid=34882477|issn=2296-701X|doi-access=free|hdl=11858/00-001M-0000-002C-DD87-4|hdl-access=free}}</ref> Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau.<ref name="Ilardo2018">{{cite journal | vauthors = Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, de Barros Damgaard P, Sikora M, Seguin-Orlando A, Rasmussen S, van den Munckhof IC, Ter Horst R, Joosten LA, Netea MG, Salingkat S, Nielsen R, Willerslev E | display-authors = 6 | title = Physiological and Genetic Adaptations to Diving in Sea Nomads | journal = Cell | volume = 173 | issue = 3 | pages = 569–580.e15 | date = April 2018 | pmid = 29677510 | doi = 10.1016/j.cell.2018.03.054 | doi-access = free }}</ref>

Human hair ranges in color from red to blond to brown to black, which is the most frequent.<ref>{{cite journal|vauthors=Rogers AR, Iltis D, Wooding S|year=2004|title=Genetic variation at the MC1R locus and the time since loss of human body hair|journal=Current Anthropology|volume=45|issue=1|pages=105–08|doi=10.1086/381006|s2cid=224795768}}</ref> Hair color depends on the amount of [[Chemistry:Melanin|melanin]], with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach, or even nearly white or colorless in cases of albinism.<ref name="roberts1">{{cite book| vauthors = Roberts D |title=Fatal Invention|publisher=The New Press|year=2011|location=London & New York}}</ref> It tends to vary clinally and generally correlates with the level of [[Physics:Ultraviolet|ultraviolet radiation]] in a particular geographic area, with darker skin mostly around the equator.<ref name="jabl04">{{cite journal|vauthors=Nina J|year=2004|title=The evolution of human skin and skin color|journal=Annual Review of Anthropology|volume=33|pages=585–623|doi=10.1146/annurev.anthro.33.070203.143955}}</ref> Skin darkening may have evolved as protection against ultraviolet solar radiation.<ref>{{cite journal | vauthors = Jablonski NG, Chaplin G | title = Colloquium paper: human skin pigmentation as an adaptation to UV radiation | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 107 | issue = Supplement_2 | pages = 8962–8968 | date = May 2010 | pmid = 20445093 | pmc = 3024016 | doi = 10.1073/pnas.0914628107 | bibcode = 2010PNAS..107.8962J | doi-access = free }}</ref> Light skin pigmentation protects against depletion of [[Chemistry:Vitamin D|vitamin D]], which requires [[Astronomy:Sunlight|sunlight]] to make.<ref>{{cite journal | vauthors = Jablonski NG, Chaplin G | title = The evolution of human skin coloration | journal = Journal of Human Evolution | volume = 39 | issue = 1 | pages = 57–106 | date = July 2000 | pmid = 10896812 | doi = 10.1006/jhev.2000.0403 | url = https://www.bgsu.edu/departments/chem/faculty/leontis/chem447/PDF_files/Jablonski_skin_color_2000.pdf | archive-url = https://web.archive.org/web/20120114203210/https://www.bgsu.edu/departments/chem/faculty/leontis/chem447/PDF_files/Jablonski_skin_color_2000.pdf | archive-date = 14 January 2012 }}</ref> Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation.<ref>{{cite journal | vauthors = Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, Dixon C, Sajantila A, Jackson IJ, Birch-Machin MA, Rees JL | display-authors = 6 | title = Evidence for variable selective pressures at MC1R | journal = American Journal of Human Genetics | volume = 66 | issue = 4 | pages = 1351–1361 | date = April 2000 | pmid = 10733465 | pmc = 1288200 | doi = 10.1086/302863 }}</ref><ref>{{cite book | vauthors = Robin A | date = 1991 | title = Biological Perspectives on Human Pigmentation | location = Cambridge | publisher = Cambridge University Press }}</ref>[[File:Seti1a.jpg|thumb|A Libyan, a Nubian, a Syrian, and an Egyptian, drawing by an unknown artist after a mural of the tomb of Seti I]]

There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level.<ref name="roberts1" /><ref name="hgp">{{cite web|title=The Science Behind the Human Genome Project|url=https://www.ornl.gov/sci/techresources/Human_Genome/project/info.shtml|url-status=dead|archive-url=https://web.archive.org/web/20130102065343/https://www.ornl.gov/sci/techresources/Human_Genome/project/info.shtml|archive-date=2 January 2013|access-date=6 January 2013|work=Human Genome Project|publisher=US Department of Energy|quote=Almost all (99.9%) nucleotide bases are exactly the same in all people.}}</ref><ref name="enr1">{{cite web| vauthors = O'Neil D | title=Ethnicity and Race: Overview|url=https://anthro.palomar.edu/ethnicity/ethnic_1.htm#return_from_ethnic_identity_question|url-status=live|archive-url=https://web.archive.org/web/20130106212622/https://anthro.palomar.edu/ethnicity/ethnic_1.htm#return_from_ethnic_identity_question|archive-date=6 January 2013|access-date=6 January 2013|publisher=Palomar College}}</ref> Much of human variation is continuous, often with no clear points of demarcation.<ref name="pmid15507998">{{cite journal | vauthors = Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN | title = Conceptualizing human variation | journal = Nature Genetics | volume = 36 | issue = 11 Suppl | pages = S17-20 | date = November 2004 | pmid = 15507998 | doi = 10.1038/ng1455 | doi-access = free }}</ref><ref name="vary02">{{cite web|title=Models of Classification|url=https://anthro.palomar.edu/vary/vary_2.htm|url-status=dead|archive-url=https://web.archive.org/web/20130106212400/https://anthro.palomar.edu/vary/vary_2.htm|archive-date=6 January 2013|access-date=6 January 2013|work=Modern Human Variation|publisher=Palomar College|vauthors=O'Neil D}}</ref><ref>{{cite journal|vauthors=Jablonski N|year=2004|title=The evolution of human skin and skin color|journal=Annual Review of Anthropology|volume=33|pages=585–623|doi=10.1146/annurev.anthro.33.070203.143955}}</ref><ref name="Palmie2007">{{cite journal|vauthors=Palmié S|date=May 2007|title=Genomics, divination, 'racecraft'|journal=American Ethnologist|volume=34|issue=2|pages=205–222|doi=10.1525/ae.2007.34.2.205}}</ref> Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups.<ref>{{cite web|title=Genetic – Understanding Human Genetic Variation|url=https://science.education.nih.gov/supplements/nih1/genetic/guide/genetic_variation1.htm|url-status=dead|archive-url=https://web.archive.org/web/20130825143543/https://science.education.nih.gov/supplements/nih1/genetic/guide/genetic_variation1.htm|archive-date=25 August 2013|access-date=13 December 2013|work=Human Genetic Variation|publisher=National Institute of Health (NIH)|quote=In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations.}}</ref><ref name="goodman1">{{cite web| vauthors = Goodman A |title=Interview with Alan Goodman|url=https://www.pbs.org/race/000_About/002_04-background-01-07.htm|url-status=live|archive-url=https://web.archive.org/web/20121029063805/https://www.pbs.org/race/000_About/002_04-background-01-07.htm|archive-date=29 October 2012|access-date=6 January 2013|work=Race Power of and Illusion|publisher=PBS}}</ref><ref>{{cite book| vauthors = Marks J |year=2010|chapter=Ten facts about human variation |title=Human Evolutionary Biology| veditors = Muehlenbein M |location=New York|publisher=Cambridge University Press|url=https://personal.uncc.edu/jmarks/pubs/tenfacts.pdf|url-status=dead|archive-url=https://web.archive.org/web/20120415012646/https://personal.uncc.edu/jmarks/pubs/tenfacts.pdf|archive-date=15 April 2012|access-date=5 September 2013}}</ref> Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other.<ref name="jablo04">{{cite journal|vauthors=Nina J|year=2004|title=The evolution of human skin and skin color|journal=Annual Review of Anthropology|volume=33|pages=585–623|doi=10.1146/annurev.anthro.33.070203.143955|quote=genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo}}</ref><ref>{{cite web|title=Overview|url=https://anthro.palomar.edu/vary/vary_1.htm|url-status=dead|archive-url=https://web.archive.org/web/20121105101522/https://anthro.palomar.edu/vary/vary_1.htm|archive-date=5 November 2012|access-date=6 January 2013|work=Modern Human Variation|publisher=Palomar College|vauthors=O'Neil D}}</ref>

Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse<ref name="Jorde2000">{{cite journal | vauthors = Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA | title = The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data | journal = American Journal of Human Genetics | volume = 66 | issue = 3 | pages = 979–988 | date = March 2000 | pmid = 10712212 | pmc = 1288178 | doi = 10.1086/302825 }}</ref> and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration.<ref name="sciencedaily.com">{{cite web |date=19 July 2007 |title=New Research Proves Single Origin Of Humans In Africa |url=https://www.sciencedaily.com/releases/2007/07/070718140829.htm |website=Science Daily |access-date=5 September 2011 |url-status=live |archive-url=https://web.archive.org/web/20111104103559/https://www.sciencedaily.com/releases/2007/07/070718140829.htm |archive-date=4 November 2011 }}</ref><ref>{{cite journal | vauthors = Manica A, Amos W, Balloux F, Hanihara T | title = The effect of ancient population bottlenecks on human phenotypic variation | journal = Nature | volume = 448 | issue = 7151 | pages = 346–348 | date = July 2007 | pmid = 17637668 | pmc = 1978547 | doi = 10.1038/nature05951 |  bibcode = 2007Natur.448..346M }}</ref> These non-African populations acquired new genetic inputs from local [[Biology:Interbreeding between archaic and modern humans|admixture with archaic populations]] and have much greater variation from Neanderthals and Denisovans than is found in Africa,<ref name="Bergstrom2020">{{cite journal | vauthors = Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, Chen Y, Felkel S, Hallast P, Kamm J, Blanché H, Deleuze JF, Cann H, Mallick S, Reich D, Sandhu MS, Skoglund P, Scally A, Xue Y, Durbin R, Tyler-Smith C | display-authors = 6 | title = Insights into human genetic variation and population history from 929 diverse genomes | journal = Science | volume = 367 | issue = 6484 | pages = eaay5012 | date = March 2020 | pmid = 32193295 | pmc = 7115999 | doi = 10.1126/science.aay5012 |quote=Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of ''private'', common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture.}}</ref> though Neanderthal admixture into African populations may be underestimated.<ref name="pmid32004458">{{cite journal | vauthors = Chen L, Wolf AB, Fu W, Li L, Akey JM | title = Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals | journal = Cell | volume = 180 | issue = 4 | pages = 677–687.e16 | date = February 2020 | pmid = 32004458 | pmc = | doi = 10.1016/j.cell.2020.01.012 | s2cid = 210955842 | doi-access = free }}</ref> Furthermore, recent studies have found that populations in [[Place:Sub-Saharan Africa|sub-Saharan Africa]], and particularly [[Place:West Africa|West Africa]], have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an [[Biology:Interbreeding between archaic and modern humans#Archaic African hominins|unknown archaic hominin]] that diverged before the split of Neanderthals and modern humans.<ref name="Bergstrom2020a">{{cite journal | vauthors = Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, Chen Y, Felkel S, Hallast P, Kamm J, Blanché H, Deleuze JF, Cann H, Mallick S, Reich D, Sandhu MS, Skoglund P, Scally A, Xue Y, Durbin R, Tyler-Smith C | display-authors = 6 | title = Insights into human genetic variation and population history from 929 diverse genomes | journal = Science | volume = 367 | issue = 6484 | pages = eaay5012 | date = March 2020 | pmid = 32193295 | pmc = 7115999 | doi = 10.1126/science.aay5012 |quote=An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations.}}</ref><ref name="Durvasula2020">{{cite journal | vauthors = Durvasula A, Sankararaman S | title = Recovering signals of ghost archaic introgression in African populations | journal = Science Advances | volume = 6 | issue = 7 | pages = eaax5097 | date = February 2020 | pmid = 32095519 | pmc = 7015685 | doi = 10.1126/sciadv.aax5097 | bibcode = 2020SciA....6.5097D |quote=Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans.}}</ref>

Humans are a [[Biology:Gonochorism|gonochoric]] species, meaning they are divided into male and female [[Biology:Sex|sex]]es.<ref>{{Cite book|url={{GBurl|id=z4pXRaZAkdkC|q=humans are dioecious genetics|p=75}}|title=Genetics: A Conceptual Approach|vauthors=Pierce BA|date=2012|publisher=Macmillan|isbn=978-1-4292-3252-4|pages=75|language=en|access-date=30 July 2022}}</ref><ref>{{Cite book|vauthors=Muehlenbein MP|url={{GBurl|id=1VXX1jkhPH8C|q=humans are dioecious biology|pg=PT57}}}|title=Human Evolutionary Biology|date=29 July 2010|publisher=Cambridge University Press|isbn=978-0-521-87948-4|veditors=Jones J|page=74|language=en|access-date=30 July 2022}}</ref><ref>{{Cite book|vauthors=Fusco G, Minelli A|url={{GBurl|id=AKGsDwAAQBAJ|q=homo sapiens gonochoric|p=304}}|title=The Biology of Reproduction|date=10 October 2019|publisher=Cambridge University Press|isbn=978-1-108-49985-9|page=304|language=en|access-date=30 July 2022}}</ref> The greatest degree of genetic [[Philosophy:Sex differences in humans|variation exists between males and females]]. While the [[Biology:Nucleotide diversity|nucleotide]] genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between [[Biology:Man|males]] and females is between 1% and 2%. Males on average are 15% heavier and {{Convert|15|cm|in|abbr=on|lk=off|0}} taller than females.<ref name="Gustafsson">{{cite journal | vauthors = Gustafsson A, Lindenfors P | title = Human size evolution: no evolutionary allometric relationship between male and female stature | journal = Journal of Human Evolution | volume = 47 | issue = 4 | pages = 253–266 | date = October 2004 | pmid = 15454336 | doi = 10.1016/j.jhevol.2004.07.004 }}</ref><ref name="NHANES_III_data">{{cite journal | vauthors = Ogden CL, Fryar CD, Carroll MD, Flegal KM | title = Mean body weight, height, and body mass index, United States 1960–2002 | journal = Advance Data | volume = | issue = 347 | pages = 1–17 | date = October 2004 | pmid = 15544194 | doi = | url = https://www.cdc.gov/nchs/data/ad/ad347.pdf | archive-url = https://archive.wikiwix.com/cache/20110223153209/https://www.cdc.gov/nchs/data/ad/ad347.pdf |archive-date=23 February 2011 }}</ref> On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers.<ref>{{cite journal | vauthors = Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG | title = Gender differences in strength and muscle fiber characteristics | journal = European Journal of Applied Physiology and Occupational Physiology | volume = 66 | issue = 3 | pages = 254–262 | year = 1993 | pmid = 8477683 | doi = 10.1007/BF00235103 | hdl-access = free | s2cid = 206772211 | hdl = 11375/22586 }}</ref> Women generally have a higher body fat percentage than men.<ref>{{Cite book | vauthors = Bredella MA |chapter=Sex Differences in Body Composition|date=2017 |title=Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity |series=Advances in Experimental Medicine and Biology|volume=1043 |pages=9–27| veditors = Mauvais-Jarvis F |place=Cham |publisher=Springer International Publishing |doi=10.1007/978-3-319-70178-3_2 |pmid=29224088|isbn=978-3-319-70177-6 }}</ref> Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and [[Biology:Lactation|lactation]].<ref>{{cite journal | vauthors = Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A | title = Male versus female skin: What dermatologists and cosmeticians should know | journal = International Journal of Women's Dermatology | volume = 4 | issue = 3 | pages = 122–130 | date = September 2018 | pmid = 30175213 | pmc = 6116811 | doi = 10.1016/j.ijwd.2018.03.002 }}</ref> As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and [[Disease|disorders]] only affect either men or women.<ref>{{cite web|vauthors=Easter C|title=Sex Linked|url=https://www.genome.gov/genetics-glossary/Sex-Linked|access-date=18 April 2021|website=National Human Genome Research Institute|language=en|archive-date=14 April 2022|archive-url=https://web.archive.org/web/20220414183337/https://www.genome.gov/genetics-glossary/Sex-Linked|url-status=live}}</ref> After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice.<ref>{{cite journal | vauthors = Puts DA, Gaulin SJ, Verdolini K | title = Dominance and the evolution of sexual dimorphism in human voice pitch. | journal = Evolution and Human Behavior | date = July 2006 | volume = 27 | issue = 4 | pages = 283–296 | doi = 10.1016/j.evolhumbehav.2005.11.003 | s2cid = 32562654 }}</ref> Women have a longer life span in almost every population around the world.<ref name="WHO">{{cite web | url = https://www.who.int/gender/documents/en/ | title = Gender, women, and health | archive-url = https://web.archive.org/web/20130625083240/https://www.who.int/gender/documents/en/ | archive-date=25 June 2013 | work = Reports from WHO 2002–2005 }}</ref> There are [[Biology:Intersex|intersex]] conditions in the human population, however these are rare.<ref>{{Cite journal |last=Sax |first=Leonard |date=1 August 2002 |title=How common is lntersex? A response to Anne Fausto‐Sterling |url=https://www.tandfonline.com/doi/full/10.1080/00224490209552139 |journal=The Journal of Sex Research |language=en |volume=39 |issue=3 |pages=174–178 |doi=10.1080/00224490209552139 |pmid=12476264 |s2cid=33795209 |issn=0022-4499}}</ref>

== Psychology ==
{{Main|Psychology}}[[File:NIA human brain drawing.jpg|thumb|Drawing of the human brain, showing several important structures]]

The [[Biology:Human brain|human brain]], the focal point of the [[Biology:Central nervous system|central nervous system]] in humans, controls the [[Biology:Peripheral nervous system|peripheral nervous system]]. In addition to controlling "lower", involuntary, or primarily autonomic activities such as [[Biology:Respiration (physiology)|respiration]] and [[Biology:Digestion|digestion]], it is also the locus of "higher" order functioning such as [[Philosophy:Thought|thought]], [[Philosophy:Reason|reason]]ing, and [[Philosophy:Abstraction|abstraction]].<ref>{{cite web | url = https://www.pbs.org/wnet/brain/3d/index.html | title = 3-D Brain Anatomy | archive-url = https://web.archive.org/web/20170905064816/https://www.pbs.org/wnet/brain/3d/index.html | archive-date=5 September 2017 | work = The Secret Life of the Brain | publisher = Public Broadcasting Service | access-date = 3 April 2005 }}</ref> These cognitive processes constitute the [[Philosophy:Mind|mind]], and, along with their behavioral consequences, are studied in the field of [[Social:Psychology|psychology]].

Humans have a larger and more developed [[Biology:Prefrontal cortex|prefrontal cortex]] than other primates, the region of the brain associated with higher [[Cognition|cognition]].<ref>{{cite journal| vauthors = Stern P |date=22 June 2018|title=The human prefrontal cortex is special|url=https://www.science.org/doi/10.1126/science.2018.360.6395.twil|journal=Science|language=en|volume=360|issue=6395|pages=1311–1312|doi=10.1126/science.360.6395.1311-g|bibcode=2018Sci...360S1311S|s2cid=149581944|issn=0036-8075|doi-access=free}}</ref> This has led humans to proclaim themselves to be more intelligent than any other known species.<ref>{{cite journal| vauthors = Erickson R |date=22 September 2014|title=Are Humans the Most Intelligent Species?|journal=Journal of Intelligence|language=en|volume=2|issue=3|pages=119–121|doi=10.3390/jintelligence2030119|issn=2079-3200|doi-access=free}}</ref> Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to.<ref>{{cite web|title=Humans not smarter than animals, just different, experts say|url=https://phys.org/news/2013-12-humans-smarter-animals-experts.html|access-date=24 October 2020|website=phys.org|language=en|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130063650/https://phys.org/news/2013-12-humans-smarter-animals-experts.html|url-status=live}}</ref>

There are some traits that, although not strictly unique, do set humans apart from other animals.<ref>{{cite web|vauthors=Robson D|title=We've got human intelligence all wrong|url=https://www.bbc.com/future/article/20161108-weve-got-human-intelligence-all-wrong|access-date=24 October 2020|website=www.bbc.com|language=en|archive-date=31 January 2021|archive-url=https://web.archive.org/web/20210131122837/https://www.bbc.com/future/article/20161108-weve-got-human-intelligence-all-wrong|url-status=live}}</ref> Humans may be the only animals who have [[Biology:Episodic memory#In animals|episodic memory]] and who can engage in "[[Philosophy:Mental time travel#Evolution and human uniqueness|mental time travel]]".<ref>{{cite news|vauthors=Owen J|date=26 February 2015|title=Many Animals{{snd}}Including Your Dog{{snd}}May Have Horrible Short-Term Memories|work=National Geographic News|url=https://www.nationalgeographic.com/animals/article/150225-dogs-memories-animals-chimpanzees-science-mind-psychology|access-date=6 September 2020|archive-date=19 April 2021|archive-url=https://web.archive.org/web/20210419150625/https://www.nationalgeographic.com/animals/article/150225-dogs-memories-animals-chimpanzees-science-mind-psychology|url-status=dead}}</ref> Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions.<ref>{{cite journal | vauthors = Schmidt KL, Cohn JF | title = Human facial expressions as adaptations: Evolutionary questions in facial expression research | journal = American Journal of Physical Anthropology | volume = 116 | issue = S33 | pages = 3–24 | date = 2001 | pmid = 11786989 | pmc = 2238342 | doi = 10.1002/ajpa.20001 }}</ref> Humans are the only animals known to cry emotional tears.<ref>{{cite news|vauthors=Moisse K|date=5 January 2011|title=Tears in Her Eyes: A Turnoff for Guys?|language=en|work=ABC News (American)|url=https://abcnews.go.com/Health/MindMoodNews/womens-tears-chemical-turnoff-men/story?id=12540975|access-date=22 April 2020|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130050944/https://abcnews.go.com/Health/MindMoodNews/womens-tears-chemical-turnoff-men/story?id=12540975|url-status=live}}</ref> Humans are one of the few animals able to self-recognize in [[Philosophy:Mirror test|mirror test]]s<ref>{{cite news|vauthors=Deleniv S|date=2018|title=The 'me' illusion: How your brain conjures up your sense of self|work=New Scientist|url=https://www.newscientist.com/article/mg23931940-100-the-me-illusion-how-your-brain-conjures-up-your-sense-of-self/|access-date=22 April 2020|archive-date=18 February 2021|archive-url=https://web.archive.org/web/20210218175649/https://www.newscientist.com/article/mg23931940-100-the-me-illusion-how-your-brain-conjures-up-your-sense-of-self/|url-status=live}}</ref> and there is also debate over to what extent humans are the only animals with a [[Philosophy:Theory of mind|theory of mind]].<ref>{{cite news|vauthors=Beck J|date=2019|title=Can We Really Know What Animals Are Thinking?|work=Snopes|url=https://www.snopes.com/news/2019/09/07/can-we-really-know-what-animals-are-thinking/|access-date=22 April 2020|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031062624/https://www.snopes.com/news/2019/09/07/can-we-really-know-what-animals-are-thinking/|url-status=live}}</ref>

=== Sleep and dreaming ===
{{Main|Biology:Sleep|Biology:Dream}}
Humans are generally [[Biology:Diurnality|diurnal]]. The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though [[Medicine:Sleep deprivation|sleep deprivation]] can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort.<ref name=Grandner2010>{{cite journal | vauthors = Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI | title = Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies | journal = Sleep Medicine Reviews | volume = 14 | issue = 4 | pages = 239–247 | date = August 2010 | pmid = 19896872 | pmc = 2888649 | doi = 10.1016/j.smrv.2009.08.001 }}</ref><!--cites previous two sentences-->

During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the [[Biology:Pons|pons]] and mostly occurs during the REM phase of sleep.<ref>{{cite web| vauthors = Ann L |date=27 January 2005|title=HowStuffWorks "Dreams: Stages of Sleep"|url=https://science.howstuffworks.com/environmental/life/human-biology/dream2.htm|url-status=dead|archive-url=https://web.archive.org/web/20120515212353/https://science.howstuffworks.com/environmental/life/human-biology/dream2.htm|archive-date=15 May 2012|access-date=11 August 2012|publisher=Science.howstuffworks.com}}</ref> The length of a dream can vary, from a few seconds up to 30 minutes.<ref name=Hobson>{{cite journal | vauthors = Hobson JA | title = REM sleep and dreaming: towards a theory of protoconsciousness | journal = Nature Reviews. Neuroscience | volume = 10 | issue = 11 | pages = 803–813 | date = November 2009 | pmid = 19794431 | doi = 10.1038/nrn2716 | s2cid = 205505278 }}</ref> Humans have three to five dreams per night, and some may have up to seven.<ref>{{cite book | vauthors = Empson J | date = 2002 | title = Sleep and dreaming | edition = 3rd | location = New York | publisher = Palgrave/St. Martin's Press }}</ref> Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of [[Biology:Lucid dream|lucid dream]]ing, where the dreamer is self-aware.<ref>{{cite web| vauthors = Lite J |date=29 July 2010|title=How Can You Control Your Dreams?|url=https://www.scientificamerican.com/article/how-to-control-dreams/|url-status=live|archive-url=https://web.archive.org/web/20150202070145/https://www.scientificamerican.com/article/how-to-control-dreams/|archive-date=2 February 2015|website=Scientific America}}</ref> Dreams can at times make a [[Philosophy:Creativity|creative]] thought occur or give a sense of inspiration.<ref>{{cite book | vauthors = Domhoff W | date = 2002 | title = The scientific study of dreams | publisher = APA Press }}</ref>

=== Consciousness and thought ===
{{Main|Philosophy:Consciousness|Cognition}}
Human consciousness, at its simplest, is [[Philosophy:Sentience|sentience]] or [[Philosophy:Awareness|awareness]] of internal or external existence.<ref name="consciousness">{{cite encyclopedia|title=Consciousness|dictionary=Merriam-Webster|access-date=4 June 2012|url=https://www.merriam-webster.com/dictionary/consciousness|archive-date=7 September 2019|archive-url=https://web.archive.org/web/20190907122314/https://www.merriam-webster.com/dictionary/consciousness|url-status=live}}</ref> Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial,<ref name="van_Gulick2004">{{cite encyclopedia|vauthors=van Gulick R|year=2004|title=Consciousness|encyclopedia=Stanford Encyclopedia of Philosophy|url=https://plato.stanford.edu/entries/consciousness/|publisher=Metaphysics Research Lab, Stanford University|access-date=30 July 2022|archive-date=14 October 2019|archive-url=https://web.archive.org/web/20191014065308/https://plato.stanford.edu/entries/consciousness/|url-status=live}}</ref> being "at once the most familiar and most mysterious aspect of our lives".<ref>{{cite book| vauthors = Schneider S, Velmans M |title=The Blackwell Companion to Consciousness |publisher=Wiley|year=2008|isbn=978-0-470-75145-9| veditors = Velmans M, Schneider S |chapter=Introduction}}</ref> The only widely agreed notion about the topic is the intuition that it exists.<ref>{{cite book| vauthors = Searle J |title=The Oxford companion to philosophy|publisher=Oxford University Press|year=2005|isbn=978-0-19-926479-7| veditors = Honderich T|chapter=Consciousness|author-link=John Searle}}</ref> Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions.<ref name="Bl">{{cite journal | vauthors = Block N | title = On a confusion about a function of consciousness. | journal = Behavioral and Brain Sciences | date = June 1995 | volume = 18 | issue = 2 | pages = 227–247 | doi = 10.1017/S0140525X00038474 | s2cid = 246244859 | doi-access = free }}</ref> It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with [[Philosophy:Introspection|introspection]], private [[Philosophy:Thought|thought]], [[Imagination|imagination]] and [[Philosophy:Volition (psychology)|volition]].<ref name="JJ3">{{cite book|vauthors=Jaynes J|url=https://s-f-walker.org.uk/pubsebooks/pdfs/Julian_Jaynes_The_Origin_of_Consciousness.pdf|title=The Origin of Consciousness in the Breakdown of the Bicameral Mind|publisher=Houghton Mifflin|year=2000|isbn=0-618-05707-2|author-link=Julian Jaynes|orig-year=1976|access-date=25 October 2020|archive-date=7 August 2019|archive-url=https://web.archive.org/web/20190807100304/https://s-f-walker.org.uk/pubsebooks/pdfs/Julian_Jaynes_The_Origin_of_Consciousness.pdf|url-status=dead}}</ref> It now often includes some kind of [[Philosophy:Experience|experience]], [[Cognition|cognition]], [[Philosophy:Feeling|feeling]] or [[Perception|perception]]. It may be 'awareness', or 'awareness of awareness', or [[Philosophy:Self-awareness|self-awareness]].<ref name="Rochat 2003 717–731">{{cite journal | vauthors = Rochat P | title = Five levels of self-awareness as they unfold early in life | journal = Consciousness and Cognition | volume = 12 | issue = 4 | pages = 717–731 | date = December 2003 | pmid = 14656513 | doi = 10.1016/s1053-8100(03)00081-3 | s2cid = 10241157 }}</ref> There might be different levels or [[Philosophy:Higher-order theories of consciousness|orders of consciousness]],<ref name="Carruthers2011">{{cite web|vauthors=Carruthers P|date=15 August 2011|title=Higher-Order Theories of Consciousness|url=https://plato.stanford.edu/entries/consciousness-higher/|access-date=31 August 2014|website=Stanford Encyclopedia of Philosophy|archive-date=13 April 2021|archive-url=https://web.archive.org/web/20210413163246/https://plato.stanford.edu/entries/consciousness-higher/|url-status=live}}</ref> or different kinds of consciousness, or just one kind with different features.<ref name="Antony2001">{{cite journal| vauthors = Antony MV |year=2001|title=Is ''consciousness'' ambiguous?|journal=Journal of Consciousness Studies|volume=8|pages=19–44}}</ref>

The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition.<ref>{{cite web|title=Cognition|url=https://www.lexico.com/definition/cognition|access-date=6 May 2020|website=Lexico|publisher=[[Organization:Oxford University Press|Oxford University Press]] and Dictionary.com|archive-date=8 July 2016|archive-url=https://web.archive.org/web/20160708041349/http://www.oxforddictionaries.com/definition/english/cognition|url-status=dead}}</ref> The human brain [[Perception|perceives]] the external world through the [[Philosophy:Sense|sense]]s, and each individual human is influenced greatly by his or her experiences, leading to [[Philosophy:Subjectivity|subjective]] views of [[Philosophy:Existence|existence]] and the passage of time.<ref>{{cite book | vauthors = Glattfelder JB | title = Information—Consciousness—Reality| chapter = The Consciousness of Reality|date=2019 |pages=515–595| veditors = Glattfelder JB |series=The Frontiers Collection|place=Cham|publisher=Springer International Publishing|language=en|doi=10.1007/978-3-030-03633-1_14|isbn=978-3-030-03633-1 | s2cid = 189379814}}</ref> The nature of thought is central to psychology and related fields. [[Philosophy:Cognitive psychology|Cognitive psychology]] studies [[Cognition|cognition]], the mental processes underlying behavior.<ref>{{cite web|title=American Psychological Association (2013). Glossary of psychological terms|url=https://www.apa.org/research/action/glossary.aspx|access-date=13 August 2014|publisher=Apa.org|archive-date=8 July 2014|archive-url=https://web.archive.org/web/20140708064652/http://www.apa.org/research/action/glossary.aspx|url-status=live}}</ref> Largely focusing on the development of the human mind through the life span, [[Social:Developmental psychology|developmental psychology]] seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age.<ref>{{cite web|title=Developmental Psychology Studies Human Development Across the Lifespan|url=https://www.apa.org/action/science/developmental/index.aspx|url-status=dead|archive-url=https://web.archive.org/web/20140709054242/https://www.apa.org/action/science/developmental/index.aspx|archive-date=9 July 2014|access-date=28 August 2017|website=www.apa.org|language=en}}</ref><ref>{{cite book| vauthors = Burman E |title=Deconstructing Developmental Psychology|publisher=Routledge|year=2017|isbn=978-1-138-84695-1|location=New York }}</ref> This may focus on intellectual, cognitive, neural, social, or [[Philosophy:Moral development|moral development]]. Psychologists have developed intelligence tests and the concept of [[Philosophy:Intelligence quotient|intelligence quotient]] in order to assess the relative intelligence of human beings and study its [[Distribution (mathematics)|distribution]] among population.<ref>{{Cite journal| vauthors = Colom R |date=1 January 2004|title=Intelligence Assessment |journal=Encyclopedia of Applied Psychology|language=en|pages=307–314|doi=10.1016/B0-12-657410-3/00510-9|isbn=978-0-12-657410-4}}</ref>

=== Motivation and emotion ===
{{Main|Philosophy:Motivation|Philosophy:Emotion}}
[[File:Plate depicting emotions of grief from Charles Darwin's book The Expression of the Emotions.jpg|right|thumb|Illustration of grief from [[Biography:Charles Darwin|Charles Darwin]]'s 1872 book ''The Expression of the Emotions in Man and Animals'']]

Human motivation is not yet wholly understood. From a psychological perspective, [[Social:Maslow's hierarchy of needs|Maslow's hierarchy of needs]] is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity.<ref>{{cite web|url=https://www.simplypsychology.org/maslow.html|title=Maslow's Hierarchy of Needs|vauthors=McLeod S|date=20 March 2020|website=Simplypsychology.org|publisher=Simply Scholar Limited|access-date=4 April 2020|quote=Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up.|archive-date=8 November 2018|archive-url=https://web.archive.org/web/20181108083314/https://www.simplypsychology.org/maslow.html|url-status=live}}</ref> From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, [[Finance:Incentive|incentive]] and [[Preference|preference]] are both factors, as are any perceived links between incentives and preferences. [[Philosophy:Volition (psychology)|Volition]] may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and [[Physics:Realisation (metrology)|realization]] of goals in an optimal manner, a [[Biology:Function|function]] beginning in childhood and continuing throughout a lifetime in a process known as [[Social:Socialization|socialization]].<ref>{{cite book| vauthors = Heckhausen J, Heckhausen H |chapter=Motivation and Action: Introduction and Overview |date=28 March 2018|title=Motivation and Action|location=Introduction and Overview|publisher=Springer, Cham|page=1|isbn=978-3-319-65093-7|doi=10.1007/978-3-319-65094-4_1}}</ref>

Emotions are biological states associated with the nervous system<ref>{{cite journal | vauthors = Damasio AR | title = Emotion in the perspective of an integrated nervous system | journal = Brain Research. Brain Research Reviews | volume = 26 | issue = 2–3 | pages = 83–86 | date = May 1998 | pmid = 9651488 | doi = 10.1016/s0165-0173(97)00064-7 | s2cid = 8504450 }}</ref><ref>{{cite book| vauthors = Ekman P, Davidson RJ |title=The Nature of emotion : fundamental questions|date=1994|publisher=Oxford University Press|isbn=978-0-19-508944-8|location=New York|pages=291–293|quote=Emotional processing, but not emotions, can occur unconsciously.}}</ref> brought on by [[Biology:Neurophysiology|neurophysiological]] changes variously associated with thoughts, feelings, behavioral responses, and a degree of [[Philosophy:Pleasure|pleasure]] or [[Social:Suffering|displeasure]].<ref>{{cite journal | vauthors = Cabanac M | date = 2002 | title = What is emotion? | journal = Behavioural Processes | volume = 60 | issue = 2 | pages = 69–83 | quote = Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) | doi = 10.1016/S0376-6357(02)00078-5 | pmid = 12426062 | s2cid = 24365776 }}</ref><ref name="Schacter">{{cite book| vauthors = Scirst DL |url= https://archive.org/details/psychology0000scha/page/310 |title=Psychology Second Edition|publisher=Worth Publishers|year=2011|isbn=978-1-4292-3719-2|location=New York|page=[https://archive.org/details/psychology0000scha/page/310 310]}}</ref> They are often intertwined with mood, [[Social:Temperament|temperament]], [[Social:Personality psychology|personality]], [[Philosophy:Disposition|disposition]], [[Philosophy:Creativity|creativity]],<ref>{{cite journal | vauthors = Averill JR | title = Individual differences in emotional creativity: structure and correlates | journal = Journal of Personality | volume = 67 | issue = 2 | pages = 331–371 | date = April 1999 | pmid = 10202807 | doi = 10.1111/1467-6494.00058 }}</ref> and motivation. Emotion has a significant influence on human behavior and their ability to learn.<ref>{{cite journal | vauthors = Tyng CM, Amin HU, Saad MN, Malik AS | title = The Influences of Emotion on Learning and Memory | journal = Frontiers in Psychology | volume = 8 | page = 1454 | date = 2017 | pmid = 28883804 | pmc = 5573739 | doi = 10.3389/fpsyg.2017.01454 | doi-access = free }}</ref> Acting on extreme or uncontrolled emotions can lead to social disorder and crime,<ref>{{cite book|vauthors=Van Gelder JL|url=https://www.researchgate.net/publication/317042659|title=Oxford Bibliographies in Criminology|publisher=Oxford University Press|date=November 2016|veditors=Wright R|chapter=Emotions in Criminal Decision Making|access-date=30 July 2022|archive-date=29 January 2021|archive-url=https://web.archive.org/web/20210129211201/https://www.researchgate.net/publication/317042659|url-status=live}}</ref> with studies showing criminals may have a lower emotional intelligence than normal.<ref>{{cite journal | vauthors = Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR | title = The relation between emotional intelligence and criminal behavior: A study among convicted criminals | journal = Industrial Psychiatry Journal | volume = 24 | issue = 1 | pages = 54–58 | date = 2015 | pmid = 26257484 | pmc = 4525433 | doi = 10.4103/0972-6748.160934 | doi-access = free }}</ref>

Emotional experiences perceived as [[Philosophy:Pleasure|pleasant]], such as joy, interest or [[Philosophy:Contentment|contentment]], contrast with those perceived as [[Social:Suffering|unpleasant]], like [[Medicine:Anxiety|anxiety]], sadness, [[Social:Anger|anger]], and [[Medicine:Depression (mood)|despair]].<ref>{{cite journal | vauthors = Fredrickson BL | title = The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions | journal = The American Psychologist | volume = 56 | issue = 3 | pages = 218–226 | date = March 2001 | pmid = 11315248 | pmc = 3122271 | doi = 10.1037/0003-066X.56.3.218 }}</ref> [[Philosophy:Happiness|Happiness]], or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the [[Philosophy:Feeling|feeling]] of positive [[Philosophy:Affect (psychology)|emotional affects]], while avoiding the negative ones.<ref>{{cite journal | vauthors = Haybron DM | title = The proper pursuit of happiness. | journal = Res Philosophica | date = August 2013 | volume = 90 | issue = 3 | pages = 387–411 | doi = 10.11612/resphil.2013.90.3.5 }}</ref><ref>{{cite web | vauthors = Haybron DM | date = 13 April 2014 | work = The Opinion Pages | publisher = The New York Times | title = Happiness and Its Discontents | url = https://opinionator.blogs.nytimes.com/2014/04/13/happiness-and-its-discontents/ | quote = I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. | access-date = 30 July 2022 | archive-date = 12 October 2018 | archive-url = https://web.archive.org/web/20181012094415/https://opinionator.blogs.nytimes.com/2014/04/13/happiness-and-its-discontents/ | url-status = live }}</ref> Others see it as an appraisal of [[Finance:Life satisfaction|life satisfaction]] or [[Philosophy:Quality of life|quality of life]].<ref>{{cite book| vauthors = Graham MC |title=Facts of Life: ten issues of contentment|date=2014|publisher=Outskirts Press|isbn=978-1-4787-2259-5|pages=6–10}}</ref> Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted.<ref>{{cite web|date=14 August 2017|title=Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy|url=https://www.sciencedaily.com/releases/2017/08/170814092813.htm|access-date=25 October 2020|website=ScienceDaily|publisher=[[Organization:American Psychological Association|American Psychological Association]]|language=en|archive-date=11 November 2020|archive-url=https://web.archive.org/web/20201111181025/https://www.sciencedaily.com/releases/2017/08/170814092813.htm|url-status=live}}</ref>

=== Sexuality and love ===
[[File:Sweet Baby Kisses Family Love.jpg|thumb|Human parents often display familial love for their children.]]
For humans, sexuality involves biological, erotic, [[Social:Physical intimacy|physical]], [[Social:Emotional intimacy|emotional]], [[Social:Social|social]], or [[Philosophy:Spirituality|spiritual]] feelings and behaviors.<ref name="S. Greenberg">{{cite book|vauthors=Greenberg JS, Bruess CE, Oswalt SB|url={{GBurl|id=8iarCwAAQBAJ|p=4}}|title=Exploring the Dimensions of Human Sexuality|publisher=Jones & Bartlett Publishers|year=2016|isbn=978-1-284-08154-1|pages=4–10|quote=Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings.|access-date=21 June 2017}}</ref><ref name="Bolin">{{cite book| vauthors = Bolin A, Whelehan P |url={{GBurl|id=qrPHYok19v8C|p=32}}|title=Human Sexuality: Biological, Psychological, and Cultural Perspectives|publisher=Taylor & Francis|year=2009|isbn=978-0-7890-2671-2|pages=32–42}}</ref> Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition.<ref name="Bolin" /> The biological and physical aspects of sexuality largely concern the human reproductive functions, including the human sexual response cycle.<ref name="S. Greenberg" /><ref name="Bolin" /> Sexuality also affects and is affected by cultural, political, legal, philosophical, [[Philosophy:Morality|moral]], ethical, and religious aspects of life.<ref name="S. Greenberg" /><ref name="Bolin" /> Sexual desire, or ''[[Philosophy:Libido|libido]]'', is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often.<ref>{{cite journal| vauthors = Younis I, Abdel-Rahman SH |date=2013|title=Sex difference in libido |journal=Human Andrology|language=en-US|volume=3|issue=4|pages=85–89|doi=10.1097/01.XHA.0000432482.01760.b0|s2cid=147235090}}</ref>

Humans can fall anywhere along a continuous scale of [[Social:Sexual orientation|sexual orientation]],<ref name="APASO">{{cite web|title=Sexual orientation, homosexuality and bisexuality|url=https://www.apa.org/helpcenter/sexual-orientation.aspx|archive-url=https://web.archive.org/web/20130808032050/https://www.apa.org/helpcenter/sexual-orientation.aspx|archive-date=8 August 2013|access-date=10 August 2013|publisher=[[Organization:American Psychological Association|American Psychological Association]]}}</ref> although most humans are heterosexual.<ref name=Bailey16 /><ref name=LeVay /> While [[Social:Homosexuality|homosexual]] behavior [[Biology:Homosexual behavior in animals|occurs in some other animals]], only humans and [[Biology:Sheep|domestic sheep]] have so far been found to exhibit exclusive preference for same-sex relationships.<ref name=Bailey16 /> Most evidence supports nonsocial, [[Philosophy:Biology and sexual orientation|biological causes of sexual orientation]],<ref name="Bailey16">{{cite journal | vauthors = Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M | title = Sexual Orientation, Controversy, and Science | journal = Psychological Science in the Public Interest | volume = 17 | issue = 2 | pages = 45–101 | date = September 2016 | pmid = 27113562 | doi = 10.1177/1529100616637616 | doi-access = free }}</ref> as cultures that are very tolerant of homosexuality do not have significantly higher rates of it.<ref name="LeVay">{{cite book|vauthors=LeVay S|url={{GBurl|id=HmQFFfa03nkC}}|title=Gay, Straight, and the Reason Why: The Science of Sexual Orientation|date=2017|publisher=Oxford University Press|isbn=978-0-19-975296-6|pages=8, 19|access-date=30 July 2022}}</ref><ref name="Balthazart">{{cite book|vauthors=Balthazart J|url={{GBurl|id=3fjGjlcVINkC}}|title=The Biology of Homosexuality|date=2012|publisher=Oxford University Press|isbn=978-0-19-983882-0|pages=13–14|access-date=30 July 2022}}</ref> Research in [[Biology:Neuroscience|neuroscience]] and [[Biology:Genetics|genetics]] suggests that other aspects of human sexuality are biologically influenced as well.<ref name=Buss2003>{{cite book | vauthors = Buss DM |year=2003 |title=The Evolution of Desire: Strategies of Human Mating. | edition = Revised |location=New York |publisher=Basic Books |isbn=978-0-465-00802-5 |url=https://archive.org/details/evolutionofdesir00buss }}</ref>

Love most commonly refers to a feeling of strong attraction or emotional attachment. It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans).<ref name="Fromm, Erich 2000">{{cite book | vauthors = Fromm E |title=The art of loving |date=2000 |publisher= Harper Perennial |location=New York |isbn=978-0-06-095828-2}}</ref> When in love [[Biology:Dopamine|dopamine]], [[Biology:Norepinephrine|norepinephrine]], [[Chemistry:Serotonin|serotonin]] and other chemicals stimulate the brain's pleasure center, leading to side effects such as increased [[Heart rate|heart rate]], loss of appetite and [[Medicine:Insomnia|sleep]], and an [[Chemistry:Euphoria|intense feeling of excitement]].<ref>{{cite web|date=14 February 2017|title=Love, Actually: The science behind lust, attraction, and companionship|url=https://sitn.hms.harvard.edu/flash/2017/love-actually-science-behind-lust-attraction-companionship/|access-date=25 October 2020|website=Science in the News|language=en-US|archive-date=28 October 2020|archive-url=https://web.archive.org/web/20201028090542/http://sitn.hms.harvard.edu/flash/2017/love-actually-science-behind-lust-attraction-companionship/|url-status=live}}</ref>

== Culture ==
{{Main|Social:Culture|Philosophy:Cultural universal}}
{{Infobox
|title=Human society statistics
|label1=Most widely spoken languages<!--PLEASE LIMIT TO TOP TEN--><ref>{{cite web|url=https://www.ethnologue.com/guides/ethnologue200|title=What are the top 200 most spoken languages?|work=Ethnologue: Languages of the World|date=2020|access-date=30 July 2022|archive-date=12 January 2013|archive-url=https://web.archive.org/web/20130112222210/http://www.ethnologue.org/ethno_docs/distribution.asp?by=size|url-status=live}}</ref><ref name=CIAWorldFactbook>{{cite report|url=https://www.cia.gov/the-world-factbook/countries/world/|title=World|work=The World Factbook|publisher=Central Intelligence Agency|access-date=15 November 2021|date=|archive-date=26 January 2021|archive-url=https://web.archive.org/web/20210126032610/https://www.cia.gov/the-world-factbook/countries/world/|url-status=live}}</ref>
|data1=[[Social:English language|English]], [[Social:Mandarin Chinese|Mandarin Chinese]], [[Social:Hindi|Hindi]], [[Social:Spanish language|Spanish]], Standard Arabic, [[Social:Bengali language|Bengali]], [[Social:French language|French]], [[Social:Russian language|Russian]], [[Social:Portuguese language|Portuguese]], [[Social:Urdu|Urdu]]<!--PLEASE LIMIT TO TOP TEN-->
|label2=Most practiced religions<ref name=CIAWorldFactbook /><ref>{{cite web|url=https://www.pewforum.org/2017/04/05/the-changing-global-religious-landscape/|date=5 April 2017|publisher=Pew Research Center|title=The Changing Global Religious Landscape|access-date=30 July 2022|archive-date=18 February 2022|archive-url=https://web.archive.org/web/20220218030628/https://www.pewforum.org/2017/04/05/the-changing-global-religious-landscape/|url-status=live}}</ref>
|data2=[[Religion:Christianity|Christianity]], [[Religion:Islam|Islam]], [[Religion:Hinduism|Hinduism]], [[Religion:Buddhism|Buddhism]], [[Religion:Folk religion|folk religion]]s, [[Religion:Sikhism|Sikhism]], [[Religion:Judaism|Judaism]], [[Religion:Irreligion|unaffiliated]]
}}
Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere.<ref>{{cite book | vauthors = Ord T |title=The Precipice: Existential Risk and the Future of Humanity |date=2020 | location = New York |publisher=Hachette Books |isbn=978-0-316-48489-3 |quote=Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence...}}</ref> Disregarding extinct hominids, humans are the only animals known to teach generalizable information,<ref>{{cite news |vauthors=Goldman JG |title=Pay attention… time for lessons at animal school |url=https://www.bbc.com/future/article/20121005-pay-attention-its-animal-school |access-date=22 April 2020 |work=bbc.com |date=2012 |language=en |archive-date=30 January 2021 |archive-url=https://web.archive.org/web/20210130120957/https://www.bbc.com/future/article/20121005-pay-attention-its-animal-school |url-status=live }}</ref> innately deploy recursive embedding to generate and communicate complex concepts,<ref>{{cite journal | vauthors = Winkler M, Mueller JL, Friederici AD, Männel C | title = Infant cognition includes the potentially human-unique ability to encode embedding | journal = Science Advances | volume = 4 | issue = 11 | pages = eaar8334 | date = November 2018 | pmid = 30474053 | pmc = 6248967 | doi = 10.1126/sciadv.aar8334 | doi-access = free | bibcode = 2018SciA....4.8334W }}</ref> engage in the "folk physics" required for competent tool design,<ref>{{cite journal | vauthors = Johnson-Frey SH | title = What's so special about human tool use? | journal = Neuron | volume = 39 | issue = 2 | pages = 201–204 | date = July 2003 | pmid = 12873378 | doi = 10.1016/S0896-6273(03)00424-0 | s2cid = 18437970 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Emery NJ, Clayton NS | title = Tool use and physical cognition in birds and mammals | journal = Current Opinion in Neurobiology | volume = 19 | issue = 1 | pages = 27–33 | date = February 2009 | pmid = 19328675 | doi = 10.1016/j.conb.2009.02.003 | quote = In short, the evidence to date that animals have an understanding of folk physics is at best mixed. | s2cid = 18277620 }}</ref> or cook food in the wild.<ref>{{cite news |vauthors=Lemonick MD |date=3 June 2015 |title=Chimps Can't Cook, But Maybe They'd Like To |url=https://www.nationalgeographic.com/news/2015/06/150602-chimp-cooking-evolution-human-brain-science/ |access-date=22 April 2020 |work=National Geographic News |archive-date=31 January 2021 |archive-url=https://web.archive.org/web/20210131064840/https://www.nationalgeographic.com/news/2015/06/150602-chimp-cooking-evolution-human-brain-science/ |url-status=dead }}</ref> Teaching and learning preserves the cultural and ethnographic identity of human societies.<ref>{{cite journal| vauthors = Vakhitova T, Gadelshina L |date=2 June 2015|title=The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education |journal=Procedia - Social and Behavioral Sciences|series=The Proceedings of 6th World Conference on educational Sciences|language=en|volume=191|pages=2565–2567|doi=10.1016/j.sbspro.2015.04.690|issn=1877-0428|doi-access=free}}</ref> Other traits and behaviors that are mostly unique to humans include starting fires,<ref>{{cite news|vauthors=McKie R|date=9 October 2018|title=The Book of Humans by Adam Rutherford review – a pithy homage to our species|language=en|work=The Guardian|url=https://www.theguardian.com/books/2018/oct/09/the-book-of-humans-adam-rutherford-review|access-date=22 April 2020|archive-date=5 February 2021|archive-url=https://web.archive.org/web/20210205084949/https://www.theguardian.com/books/2018/oct/09/the-book-of-humans-adam-rutherford-review|url-status=live}}</ref> [[Social:Phoneme|phoneme]] structuring<ref>{{cite news|vauthors=Nicholls H|date=29 June 2015|title=Babblers speak to the origin of language|work=The Guardian|url=https://www.theguardian.com/science/animal-magic/2015/jun/29/babblers-birds-origin-evolution-language|access-date=22 April 2020|archive-date=31 January 2021|archive-url=https://web.archive.org/web/20210131120059/https://www.theguardian.com/science/animal-magic/2015/jun/29/babblers-birds-origin-evolution-language|url-status=live}}</ref> and [[Philosophy:Vocal learning|vocal learning]].<ref>{{cite news|vauthors=Dasgupta S|date=2015|title=Can any animals talk and use language like humans?|language=en|work=bbc.com|url=https://www.bbc.com/earth/story/20150216-can-any-animals-talk-like-humans|access-date=22 April 2020|quote=Most animals are not vocal learners.|archive-date=2 May 2020|archive-url=https://web.archive.org/web/20200502172910/http://www.bbc.com/earth/story/20150216-can-any-animals-talk-like-humans|url-status=live}}</ref>

=== Language ===
{{Main|Social:Language}}
[[File:Primary Human Languages Improved Version.png|upright=1.5|thumb|Principal [[Social:List of language families|language families]] of the world (and in some cases geographic groups of families). For greater detail, see ''Distribution of languages in the world''.]]
While many species [[Biology:Animal communication|communicate]], [[Social:Language|language]] is unique to humans, a defining feature of humanity, and a [[Philosophy:Cultural universal|cultural universal]].<ref>{{cite web | vauthors = Scott-Phillips TC, Blythe RA | date = 18 September 2013 | title = Why is language unique to humans? | publisher = Royal Society | url = https://royalsociety.org/news/2013/language-unique-humans/ | access-date = 24 October 2020 | language = en-gb | archive-date = 18 January 2021 | archive-url = https://web.archive.org/web/20210118210915/https://royalsociety.org/news/2013/language-unique-humans/ | url-status = live }}</ref> Unlike the limited systems of other animals, human language is open{{snd}}an infinite number of meanings can be produced by combining a limited number of symbols.<ref>{{cite journal | vauthors = Pagel M | title = Q&A: What is human language, when did it evolve and why should we care? | journal = BMC Biology | volume = 15 | issue = 1 | page = 64 | date = July 2017 | pmid = 28738867 | pmc = 5525259 | doi = 10.1186/s12915-017-0405-3 | doi-access = free }}</ref><ref>{{cite journal| vauthors = Fitch WT |date=4 December 2010|title=Language evolution: How to hear words long silenced |journal=New Scientist|language=en|volume=208|issue=2789|pages=ii–iii|doi=10.1016/S0262-4079(10)62961-2|bibcode=2010NewSc.208D...2F|issn=0262-4079}}</ref> Human language also has the capacity of [[Social:Displacement (linguistics)|displacement]], using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors.<ref name="Revolution" />

Language differs from other forms of communication in that it is modality independent; the same meanings can be conveyed through different media, audibly in speech, visually by [[Social:Sign language|sign language]] or writing, and through tactile media such as [[Braille|braille]].<ref>{{cite book | vauthors = Lian A | chapter = The Modality-Independent Capacity of Language: A Milestone of Evolution|date=2016 | title = Language Evolution and Developmental Impairments|pages=229–255| veditors = Lian A |place=London|publisher=Palgrave Macmillan UK|language=en|doi=10.1057/978-1-137-58746-6_7|isbn=978-1-137-58746-6 }}</ref> Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups.<ref>{{cite web|title=Culture {{!}} United Nations For Indigenous Peoples|url=https://www.un.org/development/desa/indigenouspeoples/mandated-areas1/culture.html|access-date=24 October 2020|website=www.un.org|date=5 June 2015|archive-date=26 November 2020|archive-url=https://web.archive.org/web/20201126163227/https://www.un.org/development/desa/indigenouspeoples/mandated-areas1/culture.html|url-status=live}}</ref> There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are [[Social:Extinct language|extinct]].<ref name="Comrie1996">{{cite book | vauthors = Comrie B, Polinsky M, Matthews S |title=The Atlas of Languages: The Origin and Development of Languages Throughout the World |year=1996 |publisher=Facts on File |location=New York |pages=13–15 |isbn=978-0-8160-3388-1}}</ref>

=== The arts ===

[[Art]] is a defining characteristic of humans and there is evidence for a relationship between creativity and language.<ref name="Morriss-Kay-2010">{{cite journal | vauthors = Morriss-Kay GM | title = The evolution of human artistic creativity | journal = Journal of Anatomy | volume = 216 | issue = 2 | pages = 158–176 | date = February 2010 | pmid = 19900185 | pmc = 2815939 | doi = 10.1111/j.1469-7580.2009.01160.x }}</ref> The earliest evidence of art was shell engravings made by ''Homo erectus'' 300,000 years before modern humans evolved.<ref>{{cite journal | vauthors = Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, Ankjærgaard C, Reimann T, Wijbrans JR, Kuiper KF, Mücher HJ, Coqueugniot H, Prié V, Joosten I, van Os B, Schulp AS, Panuel M, van der Haas V, Lustenhouwer W, Reijmer JJ, Roebroeks W | display-authors = 6 | title = Homo erectus at Trinil on Java used shells for tool production and engraving | journal = Nature | volume = 518 | issue = 7538 | pages = 228–231 | date = February 2015 | pmid = 25470048 | doi = 10.1038/nature13962 | s2cid = 4461751 | bibcode = 2015Natur.518..228J }}</ref> Art attributed to ''H. sapiens'' existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa.<ref>{{cite news|vauthors=St Fleur N|date=12 September 2018|title=Oldest Known Drawing by Human Hands Discovered in South African Cave|newspaper=The New York Times|url=https://www.nytimes.com/2018/09/12/science/oldest-drawing-ever-found.html|access-date=20 September 2018|archive-date=14 April 2020|archive-url=https://web.archive.org/web/20200414094752/https://www.nytimes.com/2018/09/12/science/oldest-drawing-ever-found.html|url-status=live}}</ref><ref>{{cite news|vauthors=Radford T|date=16 April 2004|title=World's oldest jewellery found in cave|language=en-GB|work=The Guardian|url=https://www.theguardian.com/world/2004/apr/16/artsandhumanities.arts|access-date=23 September 2020|issn=0261-3077|archive-date=12 February 2021|archive-url=https://web.archive.org/web/20210212095737/https://www.theguardian.com/world/2004/apr/16/artsandhumanities.arts|url-status=live}}</ref> There are various hypotheses as to why humans have [[Biology:Adaptation|adapted]] to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate.<ref>{{cite book| vauthors = Dissanayake E |title=World Art Studies: Exploring Concepts and Approaches|publisher=Valiz|year=2008| veditors = Zijlmans K, van Damme W |location=Amsterdam|pages=241–263|chapter=The Arts after Darwin: Does Art have an Origin and Adaptive Function? }}</ref> The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage.<ref name="Morriss-Kay-2010" />

Evidence of humans engaging in musical activities predates cave art and so far music has been [[Philosophy:Cultural universal|practiced by virtually all known human cultures]].<ref name="Morley-2014">{{cite journal | vauthors = Morley I | title = A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour | journal = Journal of Anthropological Sciences = Rivista di Antropologia | volume = 92 | issue = 92 | pages = 147–177 | date = 2014 | pmid = 25020016 | doi = 10.4436/JASS.92008 }}</ref> There exists a wide variety of music genres and ethnic musics; with humans' musical abilities being related to other abilities, including complex social human behaviours.<ref name="Morley-2014" /> It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called [[Biology:Entrainment (biomusicology)|entrainment]].<ref>{{cite journal | vauthors = Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P | title = Getting the beat: entrainment of brain activity by musical rhythm and pleasantness | journal = NeuroImage | volume = 103 | pages = 55–64 | date = December 2014 | pmid = 25224999 | doi = 10.1016/j.neuroimage.2014.09.009 | s2cid = 4727529 | url = https://hal.archives-ouvertes.fr/hal-02446627/file/Trost2014_UncorrectedProof.pdf }}</ref> Dance is also a form of human expression found in all cultures<ref>{{cite journal | vauthors = Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL | title = Dance and the brain: a review | journal = Annals of the New York Academy of Sciences | volume = 1337 | issue = 1 | pages = 140–146 | date = March 2015 | pmid = 25773628 | doi = 10.1111/nyas.12632 | s2cid = 206224849 | bibcode = 2015NYASA1337..140K }}</ref> and may have evolved as a way to help early humans communicate.<ref>{{cite web|date=22 March 2010|vauthors=Chow D|title=Why Do Humans Dance?|url=https://www.livescience.com/8132-humans-dance.html|access-date=21 September 2020|website=livescience.com|language=en|archive-date=1 February 2021|archive-url=https://web.archive.org/web/20210201180750/https://www.livescience.com/8132-humans-dance.html|url-status=live}}</ref> Listening to music and observing dance stimulates the [[Biology:Orbitofrontal cortex|orbitofrontal cortex]] and other pleasure sensing areas of the brain.<ref>{{cite web|vauthors=Krakauer J|date=26 September 2008|title=Why do we like to dance{{snd}}And move to the beat?|url=https://www.scientificamerican.com/article/experts-dance/|access-date=21 September 2020|website=Scientific American|language=en|archive-date=28 February 2021|archive-url=https://web.archive.org/web/20210228035904/https://www.scientificamerican.com/article/experts-dance/|url-status=live}}</ref>

Unlike speaking, reading and writing does not come naturally to humans and must be taught.<ref>{{cite web|vauthors=Prior KS|date=21 June 2013|title=How Reading Makes Us More Human|url=https://www.theatlantic.com/national/archive/2013/06/how-reading-makes-us-more-human/277079/|access-date=23 September 2020|website=The Atlantic|language=en-US|archive-date=29 January 2021|archive-url=https://web.archive.org/web/20210129222006/https://www.theatlantic.com/national/archive/2013/06/how-reading-makes-us-more-human/277079/|url-status=live}}</ref> Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes.<ref name="Puchner">{{cite web|vauthors=Puchner M|title=How stories have shaped the world|url=https://www.bbc.com/culture/article/20180423-how-stories-have-shaped-the-world|access-date=23 September 2020|website=www.bbc.com|language=en|archive-date=5 January 2021|archive-url=https://web.archive.org/web/20210105053111/https://www.bbc.com/culture/article/20180423-how-stories-have-shaped-the-world|url-status=live}}</ref> One of the oldest surviving works of literature is the ''Epic of Gilgamesh'', first engraved on ancient [[History:Babylonia|Babylonia]]n tablets about 4,000 years ago.<ref>{{cite book| editor-first = Stephanie | editor-last=Dalley |  title=Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others|publisher=Oxford University Press|year=2000|isbn=978-0-19-283589-5|edition=revised|page=41}}</ref> Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate.<ref>{{cite journal|vauthors=Hernadi P|date=2001|title=Literature and Evolution|url=https://www.jstor.org/stable/3685504|journal=SubStance|volume=30|issue=1/2|pages=55–71|doi=10.2307/3685504|jstor=3685504|issn=0049-2426|access-date=30 July 2022|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130052249/https://www.jstor.org/stable/3685504|url-status=live}}</ref> Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation.<ref name="Puchner" />

=== Tools and technologies ===
{{Main|Engineering:Tool|Engineering:Technology}}
[[File:JR-Maglev-MLX01-2.jpg|alt=Train running on a track|thumb|The [[Physics:SCMaglev|SCMaglev]], the fastest train in the world clocking in at {{cvt|603|km/h|mph|0}} as of 2015<ref>{{cite news|vauthors=McCurry J|date=21 April 2015|title=Japan's Maglev Train Breaks World Speed Record with 600&nbsp;km/h Test Run|edition=U.S.|work=The Guardian|location=New York|url=https://www.theguardian.com/world/2015/apr/21/japans-maglev-train-notches-up-new-world-speed-record-in-test-run|access-date=30 July 2022|archive-date=18 June 2022|archive-url=https://web.archive.org/web/20220618083538/https://www.theguardian.com/world/2015/apr/21/japans-maglev-train-notches-up-new-world-speed-record-in-test-run|url-status=live}}</ref>]]
Stone tools were used by proto-humans at least 2.5&nbsp;million years ago.<ref name="Clark1994">{{cite journal | author1 = Clark JD |  author2=de Heinzelin J |  author3=Schick KD |  author4=Hart WK | author4-link= | author5=White TD | author5-link=Tim D. White | author6=WoldeGabriel G | author6-link= | author7=Walter RC | author7-link= | author8=Suwa G | author8-link=Gen Suwa | author9=Asfaw B | author9-link=Berhane Asfaw | author10=Vrba E | author10-link=Elisabeth Vrba | author11=H.-Selassie Y | author11-link=Yohannes Haile-Selassie | title = African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia | journal = Science | volume = 264 | issue = 5167 | pages = 1907–1910 | date = June 1994 | pmid = 8009220 | doi = 10.1126/science.8009220 | bibcode = 1994Sci...264.1907C }}</ref> The use and manufacture of tools has been put forward as the ability that defines humans more than anything else<ref name="Choi-2009">{{cite web|date=11 November 2009|vauthors=Choi CQ|title=Human Evolution: The Origin of Tool Use|url=https://www.livescience.com/7968-human-evolution-origin-tool.html|access-date=9 October 2020|website=livescience.com|language=en|archive-date=4 October 2020|archive-url=https://web.archive.org/web/20201004144848/https://www.livescience.com/7968-human-evolution-origin-tool.html|url-status=live}}</ref> and has historically been seen as an important evolutionary step.<ref>{{cite journal | vauthors = Orban GA, Caruana F | title = The neural basis of human tool use | journal = Frontiers in Psychology | volume = 5 | page = 310 | date = 2014 | pmid = 24782809 | pmc = 3988392 | doi = 10.3389/fpsyg.2014.00310 | doi-access = free }}</ref> The technology became much more sophisticated about 1.8 million years ago,<ref name="Choi-2009" /> with the [[Biology:Control of fire by early humans|controlled use of fire]] beginning around 1&nbsp;million years ago.<ref>{{cite journal | vauthors = Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M | title = Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 109 | issue = 20 | pages = E1215-20 | date = May 2012 | pmid = 22474385 | pmc = 3356665 | doi = 10.1073/pnas.1117620109 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Gowlett JA | title = The discovery of fire by humans: a long and convoluted process | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 371 | issue = 1696 | page = 20150164 | date = June 2016 | pmid = 27216521 | pmc = 4874402 | doi = 10.1098/rstb.2015.0164 }}</ref> The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC.<ref name="Bodnár-2018" /> The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated, thus proving essential in the development of [[Earth:Agriculture|agriculture]]{{snd}}what is known as the [[History:Neolithic Revolution|Neolithic Revolution]].<ref>{{cite web|date=2018|title=Neolithic Era Tools: Inventing a New Age|url=https://www.magellantv.com/articles/tools-of-the-neolithic-era-inventing-a-new-age|access-date=9 October 2020|website=MagellanTV|vauthors=Damiano J|archive-date=5 January 2021|archive-url=https://web.archive.org/web/20210105053059/https://www.magellantv.com/articles/tools-of-the-neolithic-era-inventing-a-new-age|url-status=live}}</ref>

China developed [[Chemistry:Paper|paper]], the printing press, [[Chemistry:Gunpowder|gunpowder]], the [[Physics:Compass|compass]] and other important inventions.<ref>{{Cite book|vauthors=Deng Y, Wang P|url=https://www.worldcat.org/oclc/671710733|title=Ancient Chinese inventions|publisher=Cambridge University Press|year=2011|isbn=978-0-521-18692-6|edition=|location=Cambridge, UK|pages=13–14|oclc=671710733|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730033309/https://www.worldcat.org/title/ancient-chinese-inventions/oclc/671710733|url-status=live}}</ref> The continued improvements in [[Engineering:Smelting|smelting]] allowed [[Engineering:Forging|forging]] of copper, bronze, iron and eventually steel, which is used in railways, [[Engineering:Skyscraper|skyscraper]]s and many other products.<ref>{{cite web|vauthors=Schifman J|date=9 July 2018|title=The Entire History of Steel|url=https://www.popularmechanics.com/technology/infrastructure/a20722505/history-of-steel/|access-date=5 May 2021|website=Popular Mechanics|language=en-US|archive-date=5 May 2021|archive-url=https://web.archive.org/web/20210505092218/https://www.popularmechanics.com/technology/infrastructure/a20722505/history-of-steel/|url-status=live}}</ref> This coincided with the [[History:Industrial Revolution|Industrial Revolution]], where the invention of automated machines brought major changes to humans' lifestyles.<ref>{{cite web|author-first=Freddie |author-last=Wilkinson|date=9 January 2020|title=Industrial Revolution and Technology|url=https://education.nationalgeographic.org/resource/industrial-revolution-and-technology/|access-date=9 October 2020|website=National Geographic Society|language=en|archive-date=30 September 2020|archive-url=https://web.archive.org/web/20200930225816/https://www.nationalgeographic.org/article/industrial-revolution-and-technology/|url-status=live}}</ref> Modern technology is observed as [[Biology:Accelerating change|progressing exponentially]],<ref>{{Cite journal|author1-last=Roser |author1-first=Max |author2-last=Ritchie |author2-first=Hannah|date=11 May 2013|title=Technological Progress|url=https://ourworldindata.org/technological-progress|journal=Our World in Data|access-date=30 July 2022|archive-date=10 September 2021|archive-url=https://web.archive.org/web/20210910043042/https://ourworldindata.org/technological-progress|url-status=live}}</ref> with major innovations in the 20th century including: [[Engineering:Electricity generation|electricity]], [[Chemistry:Penicillin|penicillin]], [[Physics:Semiconductor|semiconductor]]s, [[Earth:Internal combustion engine|internal combustion engine]]s, the [[Internet]], [[Chemistry:Fertilizer|nitrogen fixing fertilisers]], [[Engineering:Airplane|airplane]]s, [[Computer|computer]]s, [[Engineering:Car|automobiles]], [[Chemistry:Combined oral contraceptive pill|contraceptive pills]], [[Physics:Nuclear fission|nuclear fission]], the green revolution, [[Social:Radio|radio]], scientific [[Biology:Plant breeding|plant breeding]], [[Engineering:Rocket|rocket]]s, [[Physics:Air conditioning|air conditioning]], [[Engineering:Television|television]] and the [[Engineering:Assembly line|assembly line]].<ref>{{cite web|vauthors=Fallows J|date=23 October 2013|title=The 50 Greatest Breakthroughs Since the Wheel|url=https://www.theatlantic.com/magazine/archive/2013/11/innovations-list/309536/|access-date=5 May 2021|website=The Atlantic|language=en|archive-date=5 May 2021|archive-url=https://web.archive.org/web/20210505064701/https://www.theatlantic.com/magazine/archive/2013/11/innovations-list/309536/|url-status=live}}</ref>

=== Religion and spirituality ===
{{Main|Religion:Religion|Philosophy:Spirituality}}
[[File:Brooklyn Museum 1992.133.4 Figure of Shango on Horseback.jpg|thumb|upright|[[Religion:Shango|Shango]], the Orisha of fire, lightning, and thunder, in the Yoruba religion, depicted on horseback]]
[[Religion:Definition of religion|Definitions of religion]] vary;<ref name="Idinopulos-1998">{{cite journal|vauthors=Idinopulos TA|date=1998|title=What Is Religion?|url=https://www.jstor.org/stable/24460821|journal=CrossCurrents|volume=48|issue=3|pages=366–380|jstor=24460821|issn=0011-1953|access-date=30 July 2022|archive-date=13 October 2020|archive-url=https://web.archive.org/web/20201013014742/https://www.jstor.org/stable/24460821|url-status=live}}</ref> according to one definition, a religion is a [[Philosophy:Belief|belief]] system concerning the [[Philosophy:Supernatural|supernatural]], [[Religion:Sacred|sacred]] or [[Philosophy:Divinity|divine]], and practices, values, institutions and rituals associated with such belief. Some religions also have a moral code. The [[Religion:Evolutionary psychology of religion|evolution]] and the history of the [[Biology:Evolutionary origin of religions|first religions]] have become areas of active scientific investigation.<ref name="Emmons2003">{{cite journal | vauthors = Emmons RA, Paloutzian RF | title = The psychology of religion | journal = Annual Review of Psychology | volume = 54 | issue = 1 | pages = 377–402 | year = 2003 | pmid = 12171998 | doi = 10.1146/annurev.psych.54.101601.145024 }}</ref><ref>{{cite web|vauthors=King BJ|date=29 March 2016|title=Chimpanzees: Spiritual But Not Religious?|url=https://www.theatlantic.com/science/archive/2016/03/chimpanzee-spirituality/475731/|access-date=8 October 2020|website=The Atlantic|language=en-US|archive-date=20 January 2021|archive-url=https://web.archive.org/web/20210120080957/https://www.theatlantic.com/science/archive/2016/03/chimpanzee-spirituality/475731/|url-status=live}}</ref><ref>{{cite journal|vauthors=Ball P|title=Complex societies evolved without belief in all-powerful deity|url=https://www.nature.com/articles/nature.2015.17040|journal=Nature News|year=2015|language=en|doi=10.1038/nature.2015.17040|s2cid=183474917|access-date=30 July 2022|archive-date=16 May 2021|archive-url=https://web.archive.org/web/20210516165439/https://www.nature.com/news/complex-societies-evolved-without-belief-in-all-powerful-deity-1.17040|url-status=live}}</ref> Credible evidence of religious behaviour dates to the [[Earth:Middle Paleolithic|Middle Paleolithic]] era (45–200 [[Physics:Tya (unit)|thousand years ago]]).<ref>{{cite journal | vauthors = Culotta E |  title = Origins. On the origin of religion | journal = Science | volume = 326 | issue = 5954 | pages = 784–787 | date = November 2009 | pmid = 19892955 | doi = 10.1126/science.326_784 | bibcode = 2009Sci...326..784C }}</ref> It may have evolved to play a role in helping enforce and encourage cooperation between humans.<ref>{{cite journal|vauthors=Atkinson QD, Bourrat P|title=Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation|url=https://www.academia.edu/3430406|journal=Evolution and Human Behavior|year=2011|language=en|volume=32|issue=1|pages=41–49|doi=10.1016/j.evolhumbehav.2010.07.008|issn=1090-5138|access-date=30 July 2022|archive-date=15 October 2020|archive-url=https://web.archive.org/web/20201015031401/https://www.academia.edu/3430406/Beliefs_about_God_the_afterlife_and_morality_support_the_role_of_supernatural_policing_in_human_cooperation|url-status=live}}</ref>

Religion manifests in diverse forms.<ref name="Idinopulos-1998" /> Religion can include a belief in life after death,<ref>{{cite journal| vauthors = Walker GC |date=1 August 2000|title=Secular Eschatology: Beliefs about Afterlife |journal=OMEGA – Journal of Death and Dying|language=en|volume=41|issue=1|pages=5–22|doi=10.2190/Q21C-5VED-GYW6-W091|s2cid=145686249|issn=0030-2228}}</ref> the origin of life, the nature of the [[Astronomy:Universe|universe]] ([[Unsolved:Religious cosmology|religious cosmology]]) and its ultimate fate ([[Unsolved:Eschatology|eschatology]]), and [[Philosophy:Morality|moral]] or ethical teachings.<ref>{{cite journal | vauthors = McKay R, Whitehouse H | title = Religion and morality | journal = Psychological Bulletin | volume = 141 | issue = 2 | pages = 447–473 | date = March 2015 | pmid = 25528346 | pmc = 4345965 | doi = 10.1037/a0038455 }}</ref> Views on [[Religion:Transcendence|transcendence]] and [[Philosophy:Immanence|immanence]] vary substantially; traditions variously espouse [[Philosophy:Monism|monism]], [[Philosophy:Deism|deism]], [[Philosophy:Pantheism|pantheism]], and [[Philosophy:Theism|theism]] (including polytheism and [[Philosophy:Monotheism|monotheism]]).<ref>{{cite web|url=https://www.degruyter.com/document/doi/10.1515/9783110698343/html|title=God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality|publisher=[[Company:De Gruyter|De Gruyter]]|date=2023|editor1=Bernhard Nitsche|editor2=Marcus Schmücker}}</ref>

Although measuring religiosity is difficult,<ref name="Hall2008">{{cite journal | vauthors = Hall DE, Meador KG, Koenig HG | title = Measuring religiousness in health research: review and critique | journal = Journal of Religion and Health | volume = 47 | issue = 2 | pages = 134–163 | date = June 2008 | pmid = 19105008 | doi = 10.1007/s10943-008-9165-2 | pmc = 8823950 | type = Submitted manuscript | s2cid = 25349208 | url = https://zenodo.org/record/1232820 | access-date = 30 July 2022 | archive-date = 30 January 2021 | archive-url = https://web.archive.org/web/20210130130503/https://zenodo.org/record/1232820 | url-status = live }}</ref> a majority of humans profess some variety of religious or spiritual belief.<ref>{{cite news|vauthors=Sherwood H|date=27 August 2018|title=Religion: why faith is becoming more and more popular|language=en-GB|work=The Guardian|url=https://www.theguardian.com/news/2018/aug/27/religion-why-is-faith-growing-and-what-happens-next|access-date=8 October 2020|issn=0261-3077|archive-date=1 March 2021|archive-url=https://web.archive.org/web/20210301113948/https://www.theguardian.com/news/2018/aug/27/religion-why-is-faith-growing-and-what-happens-next|url-status=live}}</ref> In 2015 the plurality were [[Religion:Christians|Christian]] followed by [[Religion:Muslims|Muslims]], [[Religion:Hindus|Hindus]] and [[Religion:Buddhism|Buddhists]].<ref>{{cite web|vauthors=Hackett C, McClendon D|date=2017|title=Christians remain world's largest religious group, but they are declining in Europe|url=https://www.pewresearch.org/fact-tank/2017/04/05/christians-remain-worlds-largest-religious-group-but-they-are-declining-in-europe/|access-date=8 October 2020|website=Pew Research Center|language=en-US|archive-date=24 November 2019|archive-url=https://web.archive.org/web/20191124021738/https://www.pewresearch.org/fact-tank/2017/04/05/christians-remain-worlds-largest-religious-group-but-they-are-declining-in-europe/|url-status=live}}</ref> As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious, including those with no religious beliefs or no identity with any religion.<ref>{{cite web|date=5 April 2017|title=The Changing Global Religious Landscape|url=https://www.pewforum.org/2017/04/05/the-changing-global-religious-landscape/|access-date=8 October 2020|website=Pew Research Center's Religion & Public Life Project|language=en-US|archive-date=18 February 2022|archive-url=https://web.archive.org/web/20220218030628/https://www.pewforum.org/2017/04/05/the-changing-global-religious-landscape/|url-status=live}}</ref>

=== Science and philosophy ===
{{Main|Science|Philosophy:Philosophy}}
[[File:Dunhuang star map.jpg|thumb|right|The Dunhuang map, a star map showing the North Polar region. China circa 700.]]
An aspect unique to humans is their ability to [[Social:Knowledge transfer|transmit knowledge]] from one generation to the next and to continually build on this information to develop tools, [[Scientific law|scientific law]]s and other advances to pass on further.<ref>{{cite web|last=Di Christina |first=Mariette |title=A Very Human Story: Why Our Species Is Special|url=https://www.scientificamerican.com/article/a-very-human-story-why-our-species-is-special/|access-date=27 September 2020|website=Scientific American|language=en|archive-date=24 November 2020|archive-url=https://web.archive.org/web/20201124160953/https://www.scientificamerican.com/article/a-very-human-story-why-our-species-is-special/|url-status=live}}</ref> This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy.<ref>{{cite encyclopedia|last1=Andersen | first1=Hanne |  last2=Hepburn |first2=Brian | title=Scientific Method|date=2020|url=https://plato.stanford.edu/archives/win2020/entries/scientific-method/|encyclopedia=The Stanford Encyclopedia of Philosophy|veditors=Zalta EN|edition=Winter 2020|publisher=Metaphysics Research Lab, Stanford University|access-date=8 October 2020|archive-date=23 February 2021|archive-url=https://web.archive.org/web/20210223174917/https://plato.stanford.edu/archives/win2020/entries/scientific-method/|url-status=live}}</ref>

[[Biography:Aristotle|Aristotle]] has been described as the first scientist,<ref>{{Cite journal|vauthors=Lo Presti R|date=2014|title=History of science: The first scientist|url=https://www.nature.com/articles/512250a|journal=Nature|language=en|volume=512|issue=7514|pages=250–251|doi=10.1038/512250a|bibcode=2014Natur.512..250L|s2cid=4394696|issn=1476-4687|access-date=30 July 2022|archive-date=13 July 2022|archive-url=https://web.archive.org/web/20220713142842/https://www.nature.com/articles/512250a|url-status=live|doi-access=free}}</ref> and preceded the rise of scientific thought through the Hellenistic period.<ref>{{Cite book|vauthors=Russo L|url=https://www.worldcat.org/oclc/883392276|title=The forgotten revolution : how science was born in 300 BC and why it had to be reborn|date=2004|isbn=978-3-642-18904-3|page=1|oclc=883392276|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730033309/https://www.worldcat.org/title/forgotten-revolution-how-science-was-born-in-300-bc-and-why-it-had-to-be-reborn/oclc/883392276|url-status=live}}</ref> Other early advances in science came from the Han Dynasty in China and during the Islamic Golden Age.<ref>{{Cite book|last=Needham |first=J |author2=Wang Ling|url=https://www.worldcat.org/oclc/779676|title=Science and civilisation in China|year=1954|isbn=0-521-05799-X|page=111|oclc=779676|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730033311/https://www.worldcat.org/title/science-and-civilisation-in-china/oclc/779676|url-status=live}}</ref><ref name="Renima-2016" /> The scientific revolution, near the end of the [[Philosophy:Renaissance|Renaissance]], led to the emergence of modern science.<ref>{{Cite book|vauthors=Henry J|url=https://www.worldcat.org/oclc/615209781|title=The scientific revolution and the origins of modern science|publisher=Palgrave Macmillan|year=2008|isbn=978-1-137-07904-6|edition=3|location=Houndsmills, Basingstoke, Hampshire|chapter=Renaissance and Revolution|oclc=615209781|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730033313/https://www.worldcat.org/title/scientific-revolution-and-the-origins-of-modern-science/oclc/615209781|url-status=live}}</ref>

A chain of events and influences led to the development of the [[Scientific method|scientific method]], a process of observation and experimentation that is used to differentiate science from [[Unsolved:Pseudoscience|pseudoscience]].<ref>{{cite web | vauthors = Hansson SO | veditors = Zalta EN |year=2017|title=Science and Pseudo-Science|url=https://plato.stanford.edu/entries/pseudo-science/|url-status=live|archive-url=https://web.archive.org/web/20170611061811/https://plato.stanford.edu/entries/pseudo-science/|archive-date=11 June 2017|access-date=3 July 2017|website=Stanford Encyclopedia of Philosophy|publisher=Metaphysics Research Lab, Stanford University}}</ref> An understanding of [[Mathematics|mathematics]] is unique to humans, although other species of animals have some [[Philosophy:Numerical cognition|numerical cognition]].<ref>{{cite book | vauthors = Olmstead MC, Kuhlmeier VA | title = Comparative Cognition | publisher = Cambridge University Press | date = 2015 | pages = 209–210 | isbn = 978-1-107-01116-8 }}</ref> All of science can be divided into three major branches, the formal sciences (e.g., [[Logic|logic]] and [[Mathematics|mathematics]]), which are concerned with formal systems, the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on [[Philosophy:Empirical observation|empirical observation]] and are in turn divided into natural sciences (e.g., [[Physics:Physics|physics]], [[Chemistry:Chemistry|chemistry]], [[Biology:Biology|biology]]) and social sciences (e.g., [[Social:Psychology|psychology]], economics, sociology).<ref>{{cite web|title=Branches of Science|url=https://pmr.uchicago.edu/sites/pmr.uchicago.edu/files/uploads/BranchesofSciencePresentation.pdf|url-status=dead|archive-url=https://web.archive.org/web/20170423062909/https://pmr.uchicago.edu/sites/pmr.uchicago.edu/files/uploads/BranchesofSciencePresentation.pdf|archive-date=23 April 2017|access-date=26 June 2017|publisher=[[Organization:University of Chicago|University of Chicago]]}}</ref>

Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live.<ref>{{cite web |title=What is Philosophy? |work=Department of Philosophy |publisher=Florida State University |url=https://philosophy.fsu.edu/undergraduate-study/why-philosophy/What-is-Philosophy |access-date=8 October 2020 |archive-date=23 February 2021 |archive-url=https://web.archive.org/web/20210223102725/https://philosophy.fsu.edu/undergraduate-study/why-philosophy/What-is-Philosophy |url-status=live }}</ref> Philosophical inquiry has been a major feature in the development of humans' intellectual history.<ref>{{cite encyclopedia |title=Philosophy |encyclopedia=Definition, Systems, Fields, Schools, & Biographies |publisher=Encyclopedia Britannica |url=https://www.britannica.com/topic/philosophy |access-date=8 October 2020 |archive-date=23 February 2021 |archive-url=https://web.archive.org/web/20210223162559/https://www.britannica.com/topic/philosophy |url-status=live }}</ref> It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings.<ref>{{cite journal|vauthors=Kaufmann F, Russell B|date=1947|title=A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day.|url=https://www.jstor.org/stable/2102800|journal=Philosophy and Phenomenological Research|volume=7|issue=3|page=461|doi=10.2307/2102800|jstor=2102800|access-date=30 July 2022|archive-date=31 March 2022|archive-url=https://web.archive.org/web/20220331234443/https://www.jstor.org/stable/2102800|url-status=live}}</ref> Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science.<ref>{{cite web|vauthors=Messerly JG|date=25 March 2016|title=What is the Difference Between Philosophy, Science, and Religion?|url=https://ieet.org/index.php/IEET2/more/messerly20160325|access-date=8 August 2020|website=ieet.org|archive-date=4 March 2021|archive-url=https://web.archive.org/web/20210304193914/https://archive.ieet.org/articles/messerly20160325.html|url-status=live}}</ref> Major fields of philosophy include [[Philosophy:Metaphysics|metaphysics]], [[Philosophy:Epistemology|epistemology]], logic, and [[Philosophy:Axiology|axiology]] (which includes [[Philosophy:Ethics|ethics]] and [[Social:Aesthetics|aesthetics]]).<ref>{{cite journal| vauthors = Hassan NR, Mingers J, Stahl B |date=4 May 2018|title=Philosophy and information systems: where are we and where should we go? |journal=European Journal of Information Systems | volume=27|issue=3|pages=263–277|doi=10.1080/0960085X.2018.1470776|s2cid=64796132|issn=0960-085X|doi-access=free}}</ref>

== Society ==
{{Main|Organization:Society}}
[[File:Indian family in Brazil posed in front of hut.jpg|thumb|upright|Humans often live in family-based social structures]]
Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, [[Philosophy:Power (social and political)|power]], [[Social:Reputation|reputation]] and other factors. The structure of [[Social:Social stratification|social stratification]] and the degree of [[Social:Social mobility|social mobility]] differs, especially between modern and traditional societies.<ref>{{cite web |title=Social Stratification |url=https://web.unitn.it/files/download/8481/srs_schizzerotto_social_stratification_2_as.pdf |url-status=dead |archive-url=https://web.archive.org/web/20180320150018/https://web.unitn.it/files/download/8481/srs_schizzerotto_social_stratification_2_as.pdf |archive-date=20 March 2018 |access-date=3 July 2017 |publisher=[[Organization:University of Trento|University of Trento]] |vauthors=Schizzerotto A}}</ref> Human groups range from the size of [[Social:Family|families]] to nations. The first form of human social organization is thought to have resembled [[Biology:Hunter-gatherer|hunter-gatherer]] [[Social:Band society|band societies]].<ref>{{cite book| vauthors = Fukuyama F |title=The origins of political order : from prehuman times to the French Revolution|date=2012|publisher=Farrar, Straus and Giroux|isbn=978-0-374-53322-9|page=53|oclc=1082411117}}</ref>

=== Gender ===
{{Main|Biology:Gender|}}

Human societies typically exhibit [[Philosophy:Gender identity|gender identities]] and [[Social:Gender role|gender role]]s that distinguish between [[Social:Masculinity|masculine]] and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their [[Biology:Sex|sex]].<ref>{{Cite book |chapter=Social Role Theory of Sex Differences and Similarities : A Current Appraisal |date=2000 |chapter-url=https://www.taylorfrancis.com/chapters/edit/10.4324/9781410605245-12/social-role-theory-sex-differences-similarities-current-appraisal |title=The Developmental Social Psychology of Gender |pages=137–188 |publisher=Psychology Press |doi=10.4324/9781410605245-12 |isbn=978-1-4106-0524-5 |access-date=10 June 2022 |archive-date=30 April 2021 |archive-url=https://web.archive.org/web/20210430212712/https://www.taylorfrancis.com/chapters/edit/10.4324/9781410605245-12/social-role-theory-sex-differences-similarities-current-appraisal |url-status=live }}</ref><ref>{{Cite encyclopedia |year=2003 |title=Gender Roles and Society |encyclopedia=Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments |publisher=ABC-CLIO |location=Santa barbara, CA |url=https://digitalcommons.library.umaine.edu/soc_facpub/1/ |last=Blackstone |first=Amy |series=Sociology School Faculty Scholarship |page=335 |editor-last=Miller |editor-first=Julia R. |editor2-last=Lerner |editor2-first=Richard M. |editor3-last=Schiamberg |editor3-first=Lawrence B. |access-date=30 July 2022 |archive-date=16 May 2022 |archive-url=https://web.archive.org/web/20220516131905/https://digitalcommons.library.umaine.edu/soc_facpub/1/ |url-status=live }}</ref> The most common categorisation is a [[Gender binary|gender binary]] of men and women.<ref name="Nadal-re-binary">{{cite book|last=Nadal|first=Kevin L.|title=The SAGE Encyclopedia of Psychology and Gender|year=2017|isbn=978-1483384276|page=401|publisher=SAGE Publications |quote=Most cultures currently construct their societies based on the understanding of gender binary{{snd}}the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization.}}</ref> Many societies recognise a third gender,<ref>{{Cite book |last=Herdt |first=Gilbert |url={{GBurl|id=8nf8DwAAQBAJ}} |title=Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History |publisher=Princeton University Press |year=2020 |isbn=978-1-942130-52-9 |location=Princeton, NJ |pages=21–83 |language=en |chapter=Third Sexes and Third Genders |access-date=30 July 2022 }}</ref> or less commonly a fourth or fifth.<ref>{{cite book|last=Trumbach|first=Randolph|year=1994|chapter=London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture|title=Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History|editor-last=Herdt|editor-first=Gilbert|pages=111–136|location=New York|publisher=Zone (MIT)|isbn=978-0-942299-82-3}}</ref><ref name="Graham">{{cite web|last=Graham|first=Sharyn|url=http://www.insideindonesia.org/weekly-articles/sulawesis-fifth-gender|title=Sulawesi's fifth gender|archive-url=https://web.archive.org/web/20141126200244/http://www.insideindonesia.org/weekly-articles/sulawesis-fifth-gender|archive-date=26 November 2014|website=Inside Indonesia|date=April–June 2001}}</ref> In some other societies, [[History:Non-binary gender|non-binary]] is used as an umbrella term for a range of gender identities that are not solely male or female.<ref name="richardsetal">{{Cite journal |last1=Richards |first1=Christina |last2=Bouman |first2=Walter Pierre |last3=Seal |first3=Leighton |last4=Barker |first4=Meg John |author4-link=Meg-John Barker |last5=Nieder |first5=Timo O. |last6=T'Sjoen |first6=Guy |date=2016 |title=Non-binary or genderqueer genders |url=https://biblio.ugent.be/publication/7279758 |url-status=live |journal=International Review of Psychiatry |volume=28 |issue=1 |pages=95–102 |doi=10.3109/09540261.2015.1106446 |pmid=26753630 |archive-url=https://web.archive.org/web/20190626224658/https://biblio.ugent.be/publication/7279758 |archive-date=26 June 2019 |access-date=9 June 2019 |hdl-access=free |s2cid=29985722 |hdl=1854/LU-7279758}}</ref>

Gender roles are often associated with a division of [[Philosophy:Social norm|norms]], practices, dress, [[Social:Social behavior|behavior]], [[Philosophy:Rights|rights]], [[Philosophy:Duty|duties]], privileges, [[Social:Social status|status]], and [[Philosophy:Power (social and political)|power]], with men enjoying more rights and privileges than women in most societies, both today and in the past.<ref>{{Cite web |last1=Ananthaswamy |first1=Anil|last2=Douglas|first2=Kate |title=The origins of sexism: How men came to rule 12,000 years ago |url=https://www.newscientist.com/article/mg23831740-400-the-origins-of-sexism-how-men-came-to-rule-12000-years-ago/ |access-date=7 March 2023 |website=New Scientist |language=en-US}}</ref> As a [[Philosophy:Social constructionism|social construct]],<ref name="www.who.int">{{Cite web |title=What do we mean by "sex" and "gender"? |url=https://apps.who.int/gender/whatisgender/en/ |url-status=dead |archive-url=https://web.archive.org/web/20170130022356/https://apps.who.int/gender/whatisgender/en/ |archive-date=30 January 2017 |access-date=26 November 2015 |publisher=[[Organization:World Health Organization|World Health Organization]]}}</ref> gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies.<ref>{{cite book |url={{GBurl|id=lc-YBRQkldAC|p=143}} |title=Essential Concepts for Healthy Living |vauthors=Alters S, Schiff W |publisher=Jones & Bartlett Publishers |year=2009 |isbn=978-0-7637-5641-3 |page=143 |access-date=3 January 2018}}</ref><ref>{{cite journal |vauthors=Fortin N |year=2005 |title=Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries |journal=Oxford Review of Economic Policy |volume=21 |issue=3 |pages=416–438 |doi=10.1093/oxrep/gri024}}</ref> Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the [[Earth:Upper Paleolithic|Upper Paleolithic]], while the [[Biology:Neanderthal|Neanderthal]]s were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal.<ref>{{Cite book |last=Dobres |first=Marcia‐Anne |author-link=Marcia-Anne Dobres |chapter=Gender in the Earliest Human Societies |date=27 November 2020 |chapter-url=https://onlinelibrary.wiley.com/doi/10.1002/9781119535812.ch11 |title=A Companion to Global Gender History |pages=183–204 |editor-last=Meade |editor-first=Teresa A. |edition=1 |publisher=Wiley |language=en |doi=10.1002/9781119535812.ch11 |isbn=978-1-119-53580-5 |access-date=10 June 2022 |editor2-last=Wiesner‐Hanks |editor2-first=Merry E. |editor2-link=Merry Wiesner-Hanks |s2cid=229399965 |archive-date=10 June 2022 |archive-url=https://web.archive.org/web/20220610113514/https://onlinelibrary.wiley.com/doi/10.1002/9781119535812.ch11 |url-status=live }}</ref>

=== Kinship ===
{{Main|Social:Kinship|}}
All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ([[Social:Consanguinity|consanguinity]]), and relations through [[Biology:Marriage|marriage]] (affinity). There is also a third type applied to [[Social:Godparent|godparent]]s or [[Social:Adoption|adoptive children]] ([[Social:Fictive kinship|fictive]]). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and [[Social:Inheritance|inheritance]].<ref>{{cite web|title=The Nature of Kinship: Overview|url=https://www2.palomar.edu/anthro/kinship/kinship_1.htm|access-date=24 October 2020|website=www2.palomar.edu|archive-date=3 December 2020|archive-url=https://web.archive.org/web/20201203230431/https://www2.palomar.edu/anthro/kinship/kinship_1.htm|url-status=live}}</ref>&nbsp;All societies have rules of [[Biology:Incest taboo|incest taboo]], according to which marriage between certain kinds of kin relations are prohibited, and some also have rules of preferential marriage with certain kin relations.<ref>{{cite journal | vauthors = Itao K, Kaneko K | title = Evolution of kinship structures driven by marriage tie and competition | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 117 | issue = 5 | pages = 2378–2384 | date = February 2020 | pmid = 31964846 | pmc = 7007516 | doi = 10.1073/pnas.1917716117 | bibcode = 2020PNAS..117.2378I | doi-access = free }}</ref>

=== Ethnicity ===
{{Main|Social:Ethnic group}}
Human ethnic groups are a social category that [[Social:Identity (social science)|identifies]] together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry, [[Social:Language|language]], [[History:History|history]], [[Organization:Society|society]], [[Social:Culture|culture]], [[Earth:Nation|nation]], [[Religion:Religion|religion]], or social treatment within their residing area.<ref>{{cite book|first=Kanchan |last=Chandra |url=https://worldcat.org/oclc/829678440|title=Constructivist theories of ethnic politics|date=2012|publisher=Oxford University Press|isbn=978-0-19-989315-7|pages=69–70|oclc=829678440|access-date=30 July 2022|archive-date=30 July 2022|archive-url=https://web.archive.org/web/20220730033538/https://www.worldcat.org/title/constructivist-theories-of-ethnic-politics/oclc/829678440|url-status=live}}</ref><ref>{{cite book| vauthors = People J, Bailey G |title=Humanity: An Introduction to Cultural Anthropology|publisher=Wadsworth Cengage learning|year=2010|edition=9th|page=389|quote=In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of ‘us’ and ‘them.’ In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population.}}</ref> Ethnicity is separate from the concept of [[Social:Race (human categorization)|race]], which is based on physical characteristics, although both are [[Philosophy:Social constructionism|socially constructed]].<ref>{{cite web|vauthors=Blackmore E|date=22 February 2019|title=Race and ethnicity: How are they different?|url=https://www.nationalgeographic.com/culture/topics/reference/race-ethnicity/|access-date=24 October 2020|website=Culture|language=en|archive-date=22 October 2020|archive-url=https://web.archive.org/web/20201022013516/https://www.nationalgeographic.com/culture/topics/reference/race-ethnicity/|url-status=dead}}</ref> Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level.<ref name="REGWG2005" /> Also, there is no generally accepted definition of what constitutes an ethnic group.<ref>{{cite journal|vauthors=Chandra K|title=What is Ethnic Identity and Does It Matter?|date=2006|url=https://www.annualreviews.org/doi/10.1146/annurev.polisci.9.062404.170715|journal=Annual Review of Political Science|language=en|volume=9|issue=1|pages=397–424|doi=10.1146/annurev.polisci.9.062404.170715|issn=1094-2939|access-date=30 July 2022|archive-date=22 April 2022|archive-url=https://web.archive.org/web/20220422004642/https://www.annualreviews.org/doi/10.1146/annurev.polisci.9.062404.170715|url-status=live|doi-access=free}}</ref> Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the [[Social:Nation state|nation state]] as the predominant form of political organization in the 19th and 20th centuries.<ref>{{cite book | vauthors = Smith AD | date = 1999 | title = Myths and Memories of the Nation. | publisher = Oxford University Press | pages = 4–7 }}</ref><ref>{{cite journal| vauthors = Banton M |year=2007|title=Max Weber on 'ethnic communities': a critique|journal=Nations and Nationalism|volume=13|issue=1|pages=19–35|doi=10.1111/j.1469-8129.2007.00271.x}}</ref><ref>{{cite book | vauthors = Delanty G, Kumar K |title=The SAGE Handbook of Nations and Nationalism |date=2006 |publisher=Sage |location=London |isbn=978-1-4129-0101-7 | page = 171 }}</ref>

=== Government and politics ===
[[File:United Nations Headquarters in New York City, view from Roosevelt Island.jpg|thumb|right|The United Nations headquarters in New York City, which houses one of the world's largest political organizations]]
As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities.<ref>{{cite book| vauthors = Christian D |url=https://archive.org/details/mapsoftimeintrod00chri|title=Maps of Time|date=2004|publisher=University of California Press|isbn=978-0-520-24476-4|url-access=registration}}</ref> Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages.<ref>{{cite web|vauthors=Cronk L, Leech BL|date=20 September 2017|title=How Did Humans Get So Good at Politics?|url=https://www.sapiens.org/evolution/human-evolution-politics/|access-date=24 October 2020|website=SAPIENS|language=en-US|archive-date=7 August 2020|archive-url=https://web.archive.org/web/20200807003627/https://www.sapiens.org/evolution/human-evolution-politics/|url-status=live}}</ref> This [[Philosophy:Cognitive flexibility|cognitive flexibility]] allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances.<ref>{{cite journal | vauthors = Zmigrod L, Rentfrow PJ, Robbins TW | title = Cognitive underpinnings of nationalistic ideology in the context of Brexit | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 115 | issue = 19 | pages = E4532–E4540 | date = May 2018 | pmid = 29674447 | pmc = 5948950 | doi = 10.1073/pnas.1708960115 | bibcode = 2018PNAS..115E4532Z | s2cid = 4993139 | doi-access = free }}</ref>

Governments create [[Philosophy:Law|law]]s and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population.<ref>{{cite web|date=14 February 2011|vauthors=Melina R|title=What Are the Different Types of Governments?|url=https://www.livescience.com/33027-what-are-the-different-types-of-governments.html|access-date=24 October 2020|website=livescience.com|language=en|archive-date=1 February 2021|archive-url=https://web.archive.org/web/20210201203345/https://www.livescience.com/33027-what-are-the-different-types-of-governments.html|url-status=live}}</ref> Approximately 47% of humans live in some form of a [[Social:Democracy|democracy]], 17% in a [[Social:Hybrid regime|hybrid regime]], and 37% in an authoritarian regime.<ref>{{cite web|work=[[The Economist Democracy Index]]|title=Democracy Index 2021: less than half the world lives in a democracy|date=February 10, 2022|publisher=[[Company:Economist Intelligence Unit|Economist Intelligence Unit]]|url=https://www.eiu.com/n/democracy-index-2021-less-than-half-the-world-lives-in-a-democracy/}}</ref> Many countries belong to international organizations and alliances; the largest of these is the {{wipe|United Nations}}, with 193 member states.<ref>{{cite web|author=Jeannie Evers|date=23 December 2012|title=international organization|url=https://education.nationalgeographic.org/resource/international-organization/|access-date=24 October 2020|website=National Geographic Society|language=en|archive-date=27 April 2017|archive-url=https://web.archive.org/web/20170427195211/http://www.nationalgeographic.org/encyclopedia/international-organization/|url-status=live}}</ref>

=== Trade and economics ===
{{Main|Social:Trade|Finance:Economics}}
[[File:Silk route.jpg|thumb|upright=1.3|The Silk Road (red) and spice trade routes (blue)]]
Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave ''Homo sapiens'' a major advantage over other hominids.<ref>{{cite journal| vauthors = Horan RD, Bulte E, Shogren JF |date=1 September 2005|title=How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction |journal=Journal of Economic Behavior & Organization|language=en|volume=58|issue=1|pages=1–29|doi=10.1016/j.jebo.2004.03.009|issn=0167-2681}}</ref> Evidence suggests early ''H. sapiens'' made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals.<ref>{{cite web|vauthors=Gibbons J|date=11 August 2015|title=Why did Neanderthals go extinct?|url=https://insider.si.edu/2015/08/why-did-neanderthals-go-extinct/|access-date=11 October 2020|website=Smithsonian Insider|language=en-US|archive-date=12 November 2020|archive-url=https://web.archive.org/web/20201112021755/https://insider.si.edu/2015/08/why-did-neanderthals-go-extinct/|url-status=live}}</ref><ref>{{cite web|author=University of Wyoming|date=24 March 2005|title=Did Use of Free Trade Cause Neanderthal Extinction?|url=https://www.newswise.com/articles/did-use-of-free-trade-cause-neanderthal-extinction|access-date=11 October 2020|website=www.newswise.com|language=en|archive-date=1 February 2021|archive-url=https://web.archive.org/web/20210201191705/https://www.newswise.com/articles/did-use-of-free-trade-cause-neanderthal-extinction|url-status=live}}</ref> Early trade likely involved materials for creating tools like [[Chemistry:Obsidian|obsidian]].<ref>{{cite web|vauthors=Polianskaya A|date=15 March 2018|title=Humans may have been trading with each for as long as 300,000 years|url=https://inews.co.uk/news/science/early-humans-trading-300000-years-135655|access-date=11 October 2020|website=inews.co.uk|language=en|archive-date=23 January 2021|archive-url=https://web.archive.org/web/20210123015959/https://inews.co.uk/news/science/early-humans-trading-300000-years-135655|url-status=live}}</ref> The first truly international trade routes were around the [[Finance:Spice trade|spice trade]] through the Roman and medieval periods.<ref>{{cite news|vauthors=Henriques M|title=How spices changed the ancient world|url=https://www.bbc.com/future/bespoke/made-on-earth/the-flavours-that-shaped-the-world/|access-date=11 October 2020|website=www.bbc.com|language=en|archive-date=25 January 2021|archive-url=https://web.archive.org/web/20210125075428/https://www.bbc.com/future/bespoke/made-on-earth/the-flavours-that-shaped-the-world/|url-status=live}}</ref>

Early human economies were more likely to be based around [[Finance:Gift economy|gift giving]] instead of a [[Finance:Barter|barter]]ing system.<ref>{{cite web|vauthors=Strauss IE|date=26 February 2016|title=The Myth of the Barter Economy|url=https://www.theatlantic.com/business/archive/2016/02/barter-society-myth/471051/|access-date=11 October 2020|website=The Atlantic|language=en-US|archive-date=15 February 2021|archive-url=https://web.archive.org/web/20210215153209/https://www.theatlantic.com/business/archive/2016/02/barter-society-myth/471051/|url-status=live}}</ref> Early [[Finance:Money|money]] consisted of commodities; the oldest being in the form of cattle and the most widely used being cowrie shells.<ref name="www.pbs.org-1996">{{cite web|title=The History of Money|url=https://www.pbs.org/wgbh/nova/article/history-money/|access-date=11 October 2020|website=www.pbs.org|date=26 October 1996 |language=en-US|archive-date=29 November 2020|archive-url=https://web.archive.org/web/20201129121807/https://www.pbs.org/wgbh/nova/article/history-money/|url-status=live}}</ref> Money has since evolved into governmental issued coins, paper and electronic money.<ref name="www.pbs.org-1996" /> Human study of economics is a [[Social:Social science|social science]] that looks at how societies distribute scarce resources among different people.<ref>{{cite web|title=Why do we need economists and the study of economics?|url=https://www.frbsf.org/education/publications/doctor-econ/2000/july/economics-economists/|access-date=23 October 2020|website=Federal Reserve Bank of San Francisco|language=en|archive-date=12 November 2020|archive-url=https://web.archive.org/web/20201112023941/https://www.frbsf.org/education/publications/doctor-econ/2000/july/economics-economists/|url-status=live}}</ref> There are massive [[Social:Economic inequality|inequalities]] in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population.<ref>{{cite web|vauthors=Sheskin M|title=The inequality delusion: Why we've got the wealth gap all wrong|url=https://www.newscientist.com/article/mg23731710-300-the-inequality-delusion-why-weve-got-the-wealth-gap-all-wrong/|access-date=24 October 2020|website=New Scientist|language=en-US|archive-date=3 February 2021|archive-url=https://web.archive.org/web/20210203042931/https://www.newscientist.com/article/mg23731710-300-the-inequality-delusion-why-weve-got-the-wealth-gap-all-wrong/|url-status=live}}</ref>

=== Conflict ===
[[File:Stele of Vultures detail 01a.jpg|thumb|A depiction of war on the Stele of the Vultures]]
Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, [[Biology:Infanticide (zoology)|infanticide]] being more common among other primates.<ref>{{cite web|vauthors=Yong E|date=28 September 2016|title=Humans: Unusually Murderous Mammals, Typically Murderous Primates|url=https://www.theatlantic.com/science/archive/2016/09/humans-are-unusually-violent-mammals-but-averagely-violent-primates/501935/|access-date=7 May 2021|website=The Atlantic|language=en|archive-date=7 May 2021|archive-url=https://web.archive.org/web/20210507121602/https://www.theatlantic.com/science/archive/2016/09/humans-are-unusually-violent-mammals-but-averagely-violent-primates/501935/|url-status=live}}</ref> Phylogenetic analysis predicts that 2% of early ''H. sapiens'' would be [[Social:Murder|murder]]ed, rising to 12% during the medieval period, before dropping to below 2% in modern times.<ref>{{cite journal | vauthors = Gómez JM, Verdú M, González-Megías A, Méndez M | title = The phylogenetic roots of human lethal violence | journal = Nature | volume = 538 | issue = 7624 | pages = 233–237 | date = October 2016 | pmid = 27680701 | doi = 10.1038/nature19758 | bibcode = 2016Natur.538..233G | s2cid = 4454927 }}</ref> There is great variation in violence between human populations with rates of homicide in societies that have legal systems and strong cultural attitudes against violence at about 0.01%.<ref>{{cite journal | vauthors = Pagel M | title = Animal behaviour: Lethal violence deep in the human lineage | journal = Nature | volume = 538 | issue = 7624 | pages = 180–181 | date = October 2016 | pmid = 27680700 | doi = 10.1038/nature19474 | bibcode = 2016Natur.538..180P | s2cid = 4459560 | url = https://centaur.reading.ac.uk/67361/1/Pagel%20N%26V%20on%20Gomez%20et%20al.pdf | access-date = 30 July 2022 | archive-date = 20 May 2022 | archive-url = https://web.archive.org/web/20220520203015/https://centaur.reading.ac.uk/67361/1/Pagel%20N%26V%20on%20Gomez%20et%20al.pdf | url-status = live }}</ref>

The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions.<ref name="Ferguson-2018">{{cite web|vauthors=Ferguson RB|date=1 September 2018|title=War Is Not Part of Human Nature|url=https://www.scientificamerican.com/article/war-is-not-part-of-human-nature/|website=Scientific American|access-date=30 July 2022|archive-date=30 January 2021|archive-url=https://web.archive.org/web/20210130124940/https://www.scientificamerican.com/article/war-is-not-part-of-human-nature/|url-status=live}}</ref> While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that.<ref name="Ferguson-2018" /> War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war.<ref>{{cite magazine | vauthors = Ferguson N | title = The Next War of the World | magazine = Foreign Affairs | date = September–October 2006 | url = https://www.foreignaffairs.com/articles/middle-east/2006-09-01/next-war-world | access-date = 30 July 2022 | archive-date = 25 April 2022 | archive-url = https://web.archive.org/web/20220425051203/https://www.foreignaffairs.com/articles/middle-east/2006-09-01/next-war-world | url-status = live }}</ref> War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. <ref>{{Cite web|url=https://www.vox.com/2015/6/23/8832311/war-casualties-600-years|title=600 years of war and peace, in one amazing chart|first=Zack|last=Beauchamp|date=June 23, 2015|website=Vox}}</ref>

== See also ==
* [[Biology:List of human evolution fossils|List of human evolution fossils]]
* <!-- {{cite journal |vauthors=Barnosky AD, Koch PL, Feranec RS, Wing SL, Shabel AB |date=October 2004 |title=Assessing the causes of late Pleistocene extinctions on the continents |journal=Science |volume=306 |issue=5693 |pages=70–75 |bibcode=2004Sci...306...70B |citeseerx=10.1.1.574.332 |doi=10.1126/science.1101476 |pmid=15459379 |s2cid=36156087}}</ref> They are the main contributor to global [[Earth:Climate change|climate change]],<ref>{{cite web |title=Climate Change 2001: Working Group I: The Scientific Basis |url=https://www.grida.no/climate/ipcc_tar/wg1/007.htm |url-status=dead |archive-url=https://web.archive.org/web/20070601014140/https://www.grida.no/climate/ipcc_tar/wg1/007.htm |archive-date=1 June 2007 |access-date=30 May 2007 |publisher=grida.no/}}</ref> which may accelerate the [[Earth:Holocene extinction|Holocene extinction]].<ref>{{cite journal |vauthors=Lewis OT |date=January 2006 |title=Climate change, species-area curves and the extinction crisis |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume=361 |issue=1465 |pages=163–171 |doi=10.1098/rstb.2005.1712 |pmc=1831839 |pmid=16553315}}</ref><ref name="Stokstad" /> -->
{{clear right}}

== Notes ==
{{Reflist|group=n}}

== References ==
{{reflist|colwidth=30em}}

== External links ==

{{Human Evolution}}
{{Hominidae nav}}
{{Apes}}

{{Taxonbar|from=Q15978631}}

[[Category:Hominini]]
[[Category:Cosmopolitan mammals]]

{{Sourceattribution|Human}}