View source for Biography:Alfred Russel Wallace

{{Short description|British naturalist (1823–1913)}}
{{Infobox scientist
| name             = Alfred Russel Wallace
|honorific_suffix  = {{post-nominals|country=GBR|OM|FRS|size=100%}}
| image            = Alfred-Russel-Wallace-c1895.jpg
| caption          = Wallace in 1895
| birth_date       = {{birth date|df=yes|1823|01|08}}
| birth_place      = Llanbadoc, Monmouthshire, Wales
| death_date       = {{death date and age|df=yes|1913|11|07|1823|01|08}}
| death_place      = Broadstone, Dorset, England
| known_for        = {{Plainlist}}
* Co-discovery of [[Biology:Natural selection|natural selection]]
* Pioneering work on [[Earth:Biogeography|biogeography]]
* Wallace Line
* Wallace effect
| author_abbrev_bot= Wallace
| field            = Exploration, [[Biology:Evolutionary biology|evolutionary biology]], [[Biology:Zoology|zoology]], [[Earth:Biogeography|biogeography]], and social reform
| prizes           = {{Plainlist}}
* Royal Medal (1868)
* Gold Medal of the {{lang|fr|[[Organization:Société de Géographie|Société de Géographie]]}} (1870)
* Darwin Medal (1890)
* Founder's Medal (1892)
* Linnean Medal (1892)
* [[Physics:Copley Medal|Copley Medal]] (1908)
* Darwin–Wallace Medal (Gold, 1908)
* Order of Merit (1908)
}}
'''Alfred Russel Wallace''' {{post-nominals|country=GBR|OM|FRS}} (8 January 1823 – 7 November 1913) was a British{{sfn|Wallace|1905b|p=34}} [[Earth:Natural history|naturalist]], explorer, geographer, anthropologist, biologist and illustrator.<ref name="Smith">{{cite web |url=https://people.wku.edu/charles.smith/wallace/FAQ.htm |title=Responses to Questions Frequently Asked About Alfred Russel Wallace |last=Smith |first=Charles H. |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref> He is best known for independently conceiving the theory of [[Biology:Evolution|evolution]] through [[Biology:Natural selection|natural selection]]. His 1858 paper on the subject was jointly published that year together with extracts from [[Biography:Charles Darwin|Charles Darwin]]'s earlier writings on the topic.<ref name="tendency"/>{{sfn|Darwin|Wallace|1858}} It spurred Darwin to set aside the "big species book" he was drafting, and quickly write an [[Abstract (summary)|abstract]] of it, published in 1859 as ''On the Origin of Species''.

Like Darwin, Wallace did extensive fieldwork, first in the Amazon River basin. He then did fieldwork in the [[Place:Malay Archipelago|Malay Archipelago]], where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the animals are largely of Asian origin, and an eastern portion where the fauna reflect [[Biology:Australasian realm|Australasia]]. He was considered the 19th century's leading expert on the geographical distribution of animal species, and is sometimes called the "father of [[Earth:Biogeography|biogeography]]".<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/chsarwin.htm |title=Alfred Russel Wallace: Evolution of an Evolutionist Introduction |last=Smith |first=Charles H. |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>

Wallace was one of the leading evolutionary thinkers of the 19th century, working on [[Earth:Aposematism|warning color<!--yes, BE uses -or- not -our- here-->ation]] in animals and [[Biology:Reinforcement (speciation)|reinforcement]] (sometimes known as the Wallace effect), a way that natural selection could contribute to [[Biology:Speciation|speciation]] by encouraging the development of barriers against [[Biology:Hybrid|hybridisation]]. Wallace's 1904 book ''Man's Place in the Universe'' was the first serious attempt by a biologist to evaluate the [[Astronomy:Planetary habitability|likelihood of life on other planets]]. He was one of the first scientists to write a serious exploration of whether there was life on [[Astronomy:Mars|Mars]].<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S730.htm |title=Is Mars Habitable?, by Alfred Russel Wallace |last=Smith |first=Charles H. |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>

Aside from scientific work, he was a social activist, critical of what he considered to be an unjust social and economic system in 19th-century Britain. His advocacy of [[Unsolved:Spiritualism|spiritualism]] and his belief in a [[Philosophy:Mind–body dualism|non-material origin]] for the higher mental faculties of humans strained his relationship with other scientists. He was one of the first prominent scientists to raise concerns over the environmental impact of human activity. He wrote prolifically on both scientific and social issues; his account of his adventures and observations during his explorations in Southeast Asia, ''The Malay Archipelago'', was both popular and highly regarded. Since its publication in 1869, it has never been out of print.

== Biography ==

=== Early life ===

Alfred Russel Wallace was born on 8 January 1823 in Llanbadoc, Monmouthshire.{{efn|Though today in Wales, Monmouthshire's status was ambiguous at the time and was even considered by some to be in England, which it borders.}}{{sfn|Wilson|2000|p=1}} He was the eighth of nine children born to Mary Anne Wallace (née Greenell) and Thomas Vere Wallace. His mother was English, while his father was of Scottish ancestry. His family claimed a connection to William Wallace, a leader of Scottish forces during the Wars of Scottish Independence in the 13th century.<ref name=WKU_bio/>

Thomas Wallace graduated in law but never practised it. He owned some income-generating property, but bad investments and failed business ventures resulted in a steady deterioration of the family's financial position. His mother was from a middle-class Hertford-based family.<ref name="WKU_bio">{{cite web |url=https://people.wku.edu/charles.smith/wallace/BIOG.htm |title=Alfred Russel Wallace: Capsule Biography |last=Smith |first=Charles H.  |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref> When Wallace was five years old, his family moved to Hertford. There he attended Hertford Grammar School until 1837, when he was aged 14. The family had financial difficulties, but this was the normal leaving age for a pupil not going on to university.<ref name="Wyhe bio sketch">{{cite web |last=van Wyhe |first=John |author-link=John van Wyhe |title=Alfred Russel Wallace. A biographical sketch |website=Wallace Online | url=http://wallace-online.org/Wallace-Bio-Sketch_John_van_Wyhe.html |access-date=22 September 2022 }}</ref>{{sfn|Wilson|2000|pp=6–10}}

[[File:Wallace Mechanics Institute (crop).jpg|thumb|left|upright|A photograph from Wallace's autobiography shows the building Wallace and his brother John designed and built for the Neath Mechanics' Institute.|alt=a building designed by Wallace and his brother]]

Wallace then moved to London to board with his older brother John, a 19-year-old apprentice builder. This was a stopgap measure until William, his oldest brother, was ready to take him on as an apprentice [[Engineering:Surveying|surveyor]]. While in London, Alfred attended lectures and read books at the London Mechanics Institute. Here he was exposed to the radical political ideas of the Welsh social reformer Robert Owen and of the English-born political theorist [[Biography:Thomas Paine|Thomas Paine]]. He left London in 1837 to live with William and work as his apprentice for six years. At the end of 1839, they moved to Kington, Herefordshire, near the Welsh border, before eventually settling at Neath in Wales. Between 1840 and 1843, Wallace worked as a land surveyor in the countryside of the west of England and Wales.{{sfn|Raby|2002|pp=77–78}}{{sfn|Slotten|2004|pp=11–14}} The [[Earth:Natural history|natural history]] of his surroundings aroused his interest, from 1841 he collected flowers and plants as an amateur botanist.<ref name="Wyhe bio sketch" />

One result of Wallace's early travels is a modern controversy about his nationality. Since he was born in Monmouthshire, some sources have considered him to be Welsh.<ref>{{cite web |title=28. Alfred Russel Wallace |publisher=100 Welsh heroes |url=http://www.100welshheroes.com/en/biography/alfredrussellwallace |access-date=23 September 2008 |url-status=dead |archive-url=https://web.archive.org/web/20100124191414/http://www.100welshheroes.com/en/biography/alfredrussellwallace |archive-date=24 January 2010}}</ref> Other historians have questioned this because neither of his parents was Welsh, his family only briefly lived in Monmouthshire, the Welsh people Wallace knew in his childhood considered him to be English, and because he consistently referred to himself as English rather than Welsh. One Wallace scholar has stated that the most reasonable interpretation is therefore that he was an Englishman born in Wales.<ref name="Smith"/>

In 1843 Wallace's father died, a decline in demand for surveying meant William's business no longer had work available.<ref name="Wyhe bio sketch" /> For a short time Wallace was unemployed, then early in 1844 he was engaged by the Collegiate School in Leicester to teach drawing, mapmaking, and surveying.{{sfn|Shermer|2002|p=53}}{{sfn|Slotten|2004|pp=22–26}} He had already read George Combe's ''The Constitution of Man'', and after Spencer Hall lectured on [[Biology:Animal magnetism|mesmerism]], Wallace as well as some of the older pupils tried it out. Wallace spent many hours at the town library in Leicester; he read ''[[An Essay on the Principle of Population]]'' by Thomas Robert Malthus, and [[Biography:Alexander von Humboldt|Alexander von Humboldt]]'s ''Personal Narrative''. Around this time, he also read Charles Darwin's ''Journal'' (''[[Biology:The Voyage of the Beagle|The Voyage of the Beagle]]''), and Charles Lyell's ''Principles of Geology''.<ref name="Wyhe bio sketch" />{{sfn|Wallace|1905a|pp=[http://wallace-online.org/content/frameset?pageseq=275&itemID=S729.1&viewtype=side 232–235], [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.1&pageseq=289 256]}} One evening Wallace met the entomologist [[Biography:Henry Walter Bates|Henry Bates]], who was 19 years old, and had published an 1843 paper on beetles in the journal ''Zoologist''. He befriended Wallace and started him collecting insects.{{sfn|Shermer|2002|p=53}}{{sfn|Slotten|2004|pp=22–26}} 

When Wallace's brother William died in March 1845; Wallace left his teaching position to assume control of his brother's firm in Neath, but his brother John and he were unable to make the business work. After a few months, he found work as a [[Engineering:Civil engineer|civil engineer]] for a nearby firm that was working on a survey for a proposed railway in the Vale of Neath. Wallace's work on the survey was largely outdoors in the countryside, allowing him to indulge his new passion for collecting insects. Wallace persuaded his brother John to join him in starting another architecture and civil engineering firm. It carried out projects including the design of a building for the Neath Mechanics' Institute, founded in 1843.<ref>{{cite web |url=http://www.tlysau.org.uk/cgi-bin/anw/search2?coll_id=11281&inst_id=35&term=Neath |title=Neath Mechanics' Institute" |url-status=dead |archive-url=https://web.archive.org/web/20131110014026/http://www.tlysau.org.uk/cgi-bin/anw/search2?coll_id=11281&inst_id=35&term=Neath |archive-date=10 November 2013 |publisher=[[Organization:Swansea University|Swansea University]] |access-date=21 April 2013}}</ref> William Jevons, the founder of that institute, was impressed by Wallace and persuaded him to give lectures there on science and engineering. In the autumn of 1846, John and he purchased a cottage near Neath, where they lived with their mother and sister Fanny (his father had died in 1843).{{sfn|Slotten|2004|pp=26–29}}{{sfn|Wilson|2000|pp=19–20}} During this period, he exchanged letters with Bates about books. He had re-read Darwin's ''Journal'', and said "As the Journal of a scientific traveller, it is second only to Humboldt's 'Personal Narrative'—as a work of general interest, perhaps superior to it." In 1845, Wallace had been convinced by Robert Chambers's anonymously published treatise on [[Philosophy:Orthogenesis|progressive development]], ''Vestiges of the Natural History of Creation'', he found Bates was more critical.{{sfn|Raby|2002|p=78}}{{sfn|Wallace|1905a|pp=[http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.1&pageseq=287 254], [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.1&pageseq=289 256]}}

=== Exploration and study of the natural world ===
[[File:Wallace map archipelago.jpg|thumb|upright=1.5|A map from ''The Malay Archipelago'' shows the physical geography of the archipelago and Wallace's travels around the area. The thin black lines indicate where Wallace travelled; the red lines indicate chains of volcanoes.|alt=Map of Wallace's travels in the Malay Archipelago]]

Inspired by the chronicles of earlier and contemporary travelling naturalists,<!-- to fit in Malay section - Ida Laura Pfeiffer--> Wallace decided to travel abroad.{{sfn|Slotten|2004|pp=34–37}} He later wrote that Darwin's ''[[Biology:The Voyage of the Beagle|Journal]]'' and [[Biography:Alexander von Humboldt|Humboldt's]] ''Personal Narrative'' were "the two works to whose inspiration I owe my determination to visit the tropics as a collector."{{sfn|Wallace|1905a|p= [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.1&pageseq=289 256]}} After reading ''A voyage up the river Amazon,'' by William Henry Edwards, Wallace and Bates estimated that by collecting and selling natural history specimens such as birds and insects they could meet their costs, with the prospect of good profits.<ref name="Wyhe bio sketch" /> They therefore engaged as their agent Samuel Stevens who would advertise and arrange sales to institutions and private collectors, for a commission of 20% on sales plus 5% on despatching freight and remittances of money.{{sfn|van Wyhe|2013|pp=34–36}}

In 1848, Wallace and Bates left for Brazil aboard the ''Mischief''. They intended to collect insects and other animal specimens in the Amazon Rainforest for their private collections, selling the duplicates to museums and collectors back in Britain to fund the trip. Wallace hoped to gather evidence of the [[Biology:Transmutation of species|transmutation of species]]. Bates and he spent most of their first year collecting near Belém, then explored inland separately, occasionally meeting to discuss their findings. In 1849, they were briefly joined by another young explorer, the botanist [[Biography:Richard Spruce|Richard Spruce]], along with Wallace's younger brother Herbert. Herbert soon left (dying two years later from [[Medicine:Yellow fever|yellow fever]]), but Spruce, like Bates, would spend over ten years collecting in South America.{{sfn|Wilson|2000|p=36}}{{sfn|Raby|2002|pp=89, 98–99, 120–121}} Wallace spent four years charting the Rio Negro, collecting specimens and making notes on the peoples and languages he encountered as well as the geography, flora, and fauna.{{sfn|Raby|2002|pp=89–95}} 

On 12 July 1852, Wallace embarked for the UK on the brig ''Helen''. After 25 days at sea, the ship's cargo caught fire, and the crew was forced to abandon ship. All the specimens Wallace had on the ship, mostly collected during the last, and most interesting, two years of his trip, were lost. He managed to save a few notes and pencil sketches, but little else. Wallace and the crew spent ten days in an open boat before being picked up by the brig ''Jordeson'', which was sailing from Cuba to London. The ''Jordeson''{{'s}} provisions were strained by the unexpected passengers, but after a difficult passage on short rations, the ship reached its destination on 1 October 1852.{{sfn|Shermer|2002|pp=72–73}}<ref name="Slotten87-88">{{harvnb|Slotten|2004|pp=84–88}}</ref>

The lost collection had been insured for £200 by Stevens.{{sfn|van Wyhe|2013|p=36}} After his return to Britain, Wallace spent 18 months in London living on the insurance payment, and selling a few specimens that had been shipped home. During this period, despite having lost almost all the notes from his South American expedition, he wrote six academic papers (including "On the Monkeys of the Amazon") and two books, ''Palm Trees of the Amazon and Their Uses'' and ''Travels on the Amazon''.{{sfn|Wilson|2000|p=45}} At the same time, he made connections with several other British naturalists.<ref name="Slotten87-88"/>{{sfn|Raby|2002|p=148}}<ref name="Bibliography"/>

From 1854 to 1862, age 31 to 39, Wallace travelled through the Malay Archipelago or [[Place:East Indies|East Indies]] (now Singapore, Malaysia and Indonesia), to collect specimens for sale and to study natural history. A set of 80 bird skeletons he collected in Indonesia are held in the Cambridge University Museum of Zoology.<ref>{{cite web |url=http://www.museum.zoo.cam.ac.uk/collections.archives/historical.significance/ |title=Historical significance |publisher=Cambridge University Museum of Zoology |date=18 April 2009 |access-date=13 March 2013 |archive-url=https://web.archive.org/web/20101119040924/https://www.museum.zoo.cam.ac.uk/collections.archives/historical.significance |archive-date=19 November 2010}}</ref> Wallace had as many as a hundred assistants who collected on his behalf. Among these, his most trusted assistant was a Malay by the name of Ali who later called himself Ali Wallace. While Wallace collected insects, many of the bird specimens were collected by his assistants; of those, Ali collected and prepared around 5000.<ref name=ali>{{cite journal |last1=Wyhe |first1=John Van |last2=Drawhorn |first2=Gerrell M. |title='I am Ali Wallace': The Malay Assistant of Alfred Russel Wallace |journal=Journal of the Malaysian Branch of the Royal Asiatic Society |volume=88 |pages=3–31 |year=2015 |doi=10.1353/ras.2015.0012 |s2cid=159453047 }}</ref> Wallace's observations of the marked zoological differences across a narrow strait in the archipelago led to his proposing the zoogeographical boundary now known as the Wallace line.{{sfn|Bowler|1989|p=193}}

Wallace collected more than 125,000 specimens in the Malay Archipelago (of which more than 83,000 were beetles). Several thousand of them represented species new to science,{{sfn|Shermer|2002|p=14}} including the gliding tree frog ''Rhacophorus nigropalmatus'', known as Wallace's [[Biology:Flying frog|flying frog]].<ref>{{cite web |url=http://wallacefund.info/file/225 |title=Wallace's Flying Frog (''Rhacophorus nigropalmatus'') |publisher=The Alfred Russel Wallace Website |accessdate=30 September 2021}}</ref> While he was exploring the archipelago, he refined his thoughts about evolution, and had his famous insight on [[Biology:Natural selection|natural selection]]. In 1858 he sent an article outlining his theory to Darwin; it was published, along with a description of Darwin's theory, that same year.{{sfn|Browne|2002|pp=35–42}}

Accounts of his studies and adventures were eventually published in 1869 as ''The Malay Archipelago''. This became one of the most popular books of scientific exploration of the 19th century, and has never been out of print. It was praised by scientists such as Darwin (to whom the book was dedicated), by Lyell, and by non-scientists such as the novelist Joseph Conrad. Conrad called the book his "favorite bedside companion" and used information from it for several of his novels, especially ''Lord Jim''.{{sfn|Slotten|2004|p=267}}


{| class="center toccolours"
|+ '''Specimens and illustrations'''
|<gallery mode="packed" heights="200px" style="line-height:130%">
File:Alfred Russel Wallace01.jpg|''[[Biology:Arenga pinnata|Arenga pinnata]]'' sketched by Wallace in Celebes, reworked by Walter Hood Fitch|alt=Wallace's sketch of a tree
File:Naturalis Biodiversity Center - RMNH.AVES.144722 2 - Mino anais anais (Lesson, 1839) - Sturnidae - bird skin specimen.jpeg|Wallace collected many specimens, such as this ''Mino anais anais'' from South West Papua, 1863.|alt=photograph of a bird specimen collected by Wallace
File:Wallace frog.jpg|An illustration from ''The Malay Archipelago'' depicts the [[Biology:Flying frog|flying frog]] that Wallace discovered.|alt=illustration of Wallace's flying frog
</gallery>
|-
| style="text-align:left" | 
|}

===Return to England, marriage and children===
[[File:Alfred Russel Wallace 1862 - Project Gutenberg eText 15997.png|thumb|upright|A photograph of Wallace taken in [[Place:Singapore|Singapore]] in 1862|alt=portrait photograph of Wallace]]

In 1862, Wallace returned to England, where he moved in with his sister Fanny Sims and her husband Thomas. While recovering from his travels, Wallace organised his collections and gave numerous lectures about his adventures and discoveries to scientific societies such as the [[Organization:Zoological Society of London|Zoological Society of London]]. Later that year, he visited Darwin at Down House, and became friendly with both Lyell and the philosopher [[Biography:Herbert Spencer|Herbert Spencer]].{{sfn|Shermer|2002|pp=151–152}} During the 1860s, Wallace wrote papers and gave lectures defending natural selection. He corresponded with Darwin about topics including [[Biology:Sexual selection|sexual selection]], warning coloration<!--yes, BE uses -or- here-->, and the possible effect of natural selection on hybridisation and the divergence of species.{{sfn|Slotten|2004|pp=249–258}} In 1865, he began investigating spiritualism.{{sfn|Slotten|2004|p=235}}

After a year of courtship, Wallace became engaged in 1864 to a young woman whom, in his autobiography, he would only identify as Miss L. Miss L. was the daughter of Lewis Leslie who played chess with Wallace,{{sfn|van Wyhe|2013|p=210}} but to Wallace's great dismay, she broke off the engagement.{{sfn|Shermer|2002|p=156}} In 1866, Wallace married Annie Mitten. Wallace had been introduced to Mitten through the botanist Richard Spruce, who had befriended Wallace in Brazil and who was a friend of Annie Mitten's father, William Mitten, an expert on mosses. In 1872, Wallace built the Dell, a house of concrete, on land he leased in Grays in Essex, where he lived until 1876. The Wallaces had three children: Herbert (1867–1874), Violet (1869–1945), and William (1871–1951).{{sfn|Slotten|2004|pp=239–240}}

=== Financial struggles ===

In the late 1860s and 1870s, Wallace was very concerned about the financial security of his family. While he was in the Malay Archipelago, the sale of specimens had brought in a considerable amount of money, which had been carefully invested by the agent who sold the specimens for Wallace. Unfortunately, on his return to the UK, Wallace made a series of bad investments in railways and mines that squandered most of the money, and he found himself badly in need of the proceeds from the publication of ''The Malay Archipelago''.{{sfn|Slotten|2004|pp=265–267}}

Despite assistance from his friends, he was never able to secure a permanent salaried position such as a curatorship in a museum. To remain financially solvent, Wallace worked grading government examinations, wrote 25 papers for publication between 1872 and 1876 for various modest sums, and was paid by Lyell and Darwin to help edit some of their own works.{{sfn|Slotten|2004|pp=299–300}}

In 1876, Wallace needed a £500 advance from the publisher of ''The Geographical Distribution of Animals'' to avoid having to sell some of his personal property.{{sfn|Slotten|2004|p=325}} Darwin was very aware of Wallace's financial difficulties and lobbied long and hard to get Wallace awarded a government pension for his lifetime contributions to science. When the £200 annual pension was awarded in 1881, it helped to stabilise Wallace's financial position by supplementing the income from his writings.{{sfn|Slotten|2004|pp=361–364}}

=== Social activism ===

In 1881, Wallace was elected as the first president of the newly formed Land Nationalisation Society. In the next year, he published a book, ''Land Nationalisation; Its Necessity and Its Aims'',<ref>{{cite book |last=Wallace |first=Alfred Russel |year=1906 |title=Land Nationalisation; Its Necessity and Its Aims |publisher=Swan Sonnenschein <!--|url=https://web.archive.org/web/20120621134408/http://wallacefund.info/land-nationalisation-its-necessity-and-its-aims-being-comparison-system-landlord-and-tenant-occupyin-->}}</ref> on the subject. He criticised the UK's [[Social:Free trade|free trade]] policies for the negative impact they had on working-class people.<ref name="Bibliography">{{cite web|url=http://people.wku.edu/charles.smith/wallace/bibintro.htm|title=Bibliography of the Writings of Alfred Russel Wallace|last=Smith |first=Charles H. |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>{{sfn|Slotten|2004|pp=365–372}} In 1889, Wallace read ''Looking Backward'' by Edward Bellamy and declared himself a socialist, despite his earlier foray as a speculative investor.{{sfn|Slotten|2004|p=436}} After reading ''Progress and Poverty'', the best selling book by the progressive land reformist Henry George, Wallace described it as "Undoubtedly the most remarkable and important book of the present century."<ref>{{cite book |last=Stanley |first=Buder |title=Visionaries and Planners: The Garden City Movement and the Modern Community |year=1990 |publisher=Oxford University Press |url=https://books.google.com/books?id=evBdKUyXY7UC |isbn=978-0195362886 |page=20 }}</ref>

Wallace opposed [[Biology:Eugenics|eugenics]], an idea supported by other prominent 19th-century evolutionary thinkers, on the grounds that contemporary society was too corrupt and unjust to allow any reasonable determination of who was fit or unfit.{{sfn|Slotten|2004|pp=436–438}} In his 1890 article "Human Selection" he wrote, "Those who succeed in the race for wealth are by no means the best or the most intelligent&nbsp;..."<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S427.htm |title=Human Selection (S427: 1890) |last=Wallace |first=Alfred Russel |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref> In 1898, Wallace wrote a paper advocating a [[Finance:Fiat money|pure paper money system, not backed by silver or gold]], which impressed the economist [[Biography:Irving Fisher|Irving Fisher]] so much that he dedicated his 1920 book ''Stabilizing the Dollar'' to Wallace.<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S557.htm |title=Paper Money as a Standard of Value (S557: 1898)|first=Alfred Russel |last=Wallace |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>

Wallace wrote on other social and political topics including to support women's suffrage, and repeatedly on the dangers and wastefulness of [[Social:Militarism|militarism]].{{sfn|Slotten|2004|pp=366, 453, 487–488}}{{sfn|Shermer|2002|pp=23, 279}} In an 1899 essay, he called for popular opinion to be rallied against warfare by showing people "that all modern wars are dynastic; that they are caused by the ambition, the interests, the jealousies, and the insatiable greed of power of their rulers, or of the great mercantile and financial classes which have power and influence over their rulers; and that the results of war are never good for the people, who yet bear all its burthens".<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S567.htm |title=The Causes of War, and the Remedies (S567: 1899) |first=Alfred Russel |last=Wallace |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref> In a letter published by the Daily Mail in 1909, with aviation in its infancy, he advocated an international treaty to ban the military use of aircraft, arguing against the idea "...that this new horror is "inevitable," and that all we can do is to be sure and be in the front rank of the aerial assassins—for surely no other term can so fitly describe the dropping of, say, ten thousand bombs at midnight into an enemy's capital from an invisible flight of airships."<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S670.htm |title=Flying Machines in War. (S670: 1909) |last=Wallace |first=Alfred Russel |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>

In 1898, Wallace published ''The Wonderful Century: Its Successes and Its Failures'', about developments in the 19th century. The first part of the book covered the major scientific and technical advances of the century; the second part covered what Wallace considered to be its social failures including the destruction and waste of wars and arms races, the rise of the urban poor and the dangerous conditions in which they lived and worked, a harsh criminal justice system that failed to reform criminals, abuses in a mental health system based on privately owned sanatoriums, the environmental damage caused by capitalism, and the evils of European colonialism.{{sfn|Slotten|2004|pp=453–455}}<ref>{{cite book |last=Wallace |first=Alfred Russel |title=The Wonderful Century: Its Successes and Its Failures |year=1903 |orig-year=1898 |publisher=Swan Sonnenschein |url=https://archive.org/details/wonderfulcentur03wallgoog |oclc=935283134 }}</ref> Wallace continued his social activism for the rest of his life, publishing the book ''The Revolt of Democracy'' just weeks before his death.<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S734.htm |title=The Revolt of Democracy (S734: 1913) |last=Wallace |first=Alfred Russel |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref>

=== Further scientific work ===

In 1880, he published ''Island Life'' as a sequel to ''The Geographic Distribution of Animals''. In November 1886, Wallace began a ten-month trip to the United States to give a series of popular lectures. Most of the lectures were on Darwinism (evolution through natural selection), but alongside that he gave speeches on [[Earth:Biogeography|biogeography]], spiritualism, and socio-economic reform. During the trip, he was reunited with his brother John who had emigrated to California years before. He spent a week in Colorado, with the American botanist Alice Eastwood as his guide, exploring the flora of the Rocky Mountains and gathering evidence that would lead him to a theory on how glaciation might explain certain commonalities between the mountain flora of Europe, Asia and North America, which he published in 1891 in the paper "English and American Flowers". He met many other prominent American naturalists and viewed their collections. His 1889 book ''Darwinism'' used information he collected on his American trip and information he had compiled for the lectures.{{sfn|Shermer|2002|pp=274–278}}{{sfn|Slotten|2004|pp=379–400}}

=== Death ===
[[File:Restored grave of AR Wallace.jpg|thumb|upright|Wallace's grave in Broadstone Cemetery, Broadstone, Dorset, which was restored by the A. R. Wallace Memorial Fund in 2000. It features a fossil tree trunk that is 7 feet (2.1 m) tall from Portland mounted on a block of Purbeck limestone.|alt=photograph of Wallace's grave]]

On 7 November 1913, Wallace died at home, aged 90, in the country house he called Old Orchard, which he had built a decade earlier.<ref name="Slotten490">{{harvnb|Slotten|2004|p=490}}</ref> His death was widely reported in the press. ''{{wipe|The New York Times}}'' called him "the last of the giants [belonging] to that wonderful group of intellectuals composed of Darwin, Huxley, Spencer, Lyell, Owen, and other scientists, whose daring investigations revolutionized and evolutionized the thought of the century".<ref>{{cite news |author=Anon |title=We Are Guarded by Spirits, Declares Dr. A. R. Wallace |newspaper={{wipe|The New York Times}} |date=8 October 1911 |url=https://people.wku.edu/charles.smith/wallace/S748A.htm }}</ref> Another commentator in the same edition said: "No apology need be made for the few literary or scientific follies of the author of that great book on the 'Malay Archipelago'."{{sfn|Slotten|2004|p=491}}

Some of Wallace's friends suggested that he be buried in Westminster Abbey, but his wife followed his wishes and had him buried in the small cemetery at Broadstone, Dorset.<ref name="Slotten490"/> Several prominent British scientists formed a committee to have a medallion of Wallace placed in Westminster Abbey near where Darwin had been buried. The medallion was unveiled on 1 November 1915.<ref>{{cite book |last=Hall |first=A. R. |title=The Abbey Scientists |page=52 |publisher=Roger & Robert Nicholson |year=1966 |oclc=2553524 }}</ref>

== Theory of evolution ==

=== Early evolutionary thinking ===

Unlike Darwin, Wallace began his career as a travelling naturalist who already believed in the transmutation of species. The concept had been advocated by Jean-Baptiste Lamarck, Geoffroy Saint-Hilaire, Erasmus Darwin, and Robert Grant, among others. It was widely discussed, but not generally accepted by leading naturalists, and was considered to have [[Social:Radicalism (historical)|radical]], even revolutionary connotations.<ref name="Larson73">{{harvnb|Larson|2004|p=73}}</ref>{{sfn|Bowler|Morus|2005|p=141}} Prominent anatomists and geologists such as [[Biography:Georges Cuvier|Georges Cuvier]], Richard Owen, Adam Sedgwick, and Lyell attacked transmutation vigorously.{{sfn|McGowan|2001|pp=101, 154–155}}{{sfn|Larson|2004|pp=23–24, 37–38}} It has been suggested that Wallace accepted the idea of the transmutation of species in part because he was always inclined to favour radical ideas in politics, religion and science,<ref name="Larson73"/> and because he was unusually open to marginal, even fringe, ideas in science.<ref name="Shermer p. 54">{{harvnb|Shermer|2002|p=54}}</ref>

Wallace was profoundly influenced by Robert Chambers's ''Vestiges of the Natural History of Creation'', a controversial work of popular science published anonymously in 1844. It advocated an evolutionary origin for the solar system, the earth, and living things.{{sfn|Slotten|2004|p=31}} Wallace wrote to Henry Bates in 1845 describing it as "an ingenious hypothesis strongly supported by some striking facts and analogies, but which remains to be proven by ... more research".<ref name="Shermer p. 54"/> In 1847, he wrote to Bates that he would "like to take some one family [of beetles] to study thoroughly, ... with a view to the theory of the origin of species."<ref>Wallace Family Archive, 11 Oct. 1847, quoted in {{harvnb|Raby|2002|p=1}}.</ref>

Wallace planned fieldwork to test the evolutionary hypothesis that closely related species should inhabit neighbouring territories.<ref name="Larson73"/> During his work in the Amazon basin, he came to realise that geographical barriers—such as the Amazon and its major tributaries—often separated the ranges of closely allied species. He included these observations in his 1853 paper "On the Monkeys of the Amazon". Near the end of the paper he asked the question, "Are very closely allied species ever separated by a wide interval of country?"{{sfn|Slotten|2004|p=94}}

In February 1855, while working in Sarawak on the island of Borneo, Wallace wrote "On the Law which has Regulated the Introduction of New Species". The paper was published in the ''Annals and Magazine of Natural History'' in September 1855.<ref>{{cite web |title=Wallace Collection – Wallace's 'Sarawak law' paper |url=http://www.nhm.ac.uk/nature-online/collections-at-the-museum/wallace-collection/closeup.jsp?itemID=138&theme=Evolution |publisher=[[Biology:Natural History Museum, London|Natural History Museum]] |year=2012 |access-date=14 February 2012 }}</ref> In this paper, he discussed observations of the geographic and geologic distribution of both living and fossil species, a field that became biogeography. His conclusion that "Every species has come into existence coincident both in space and time with a closely allied species" has come to be known as the "Sarawak Law", answering his own question in his paper on the monkeys of the Amazon basin. Although it does not mention possible mechanisms for evolution, this paper foreshadowed the momentous paper he would write three years later.<ref>{{cite web |last=Wallace |first=Alfred Russel |title=On the Law Which has Regulated the Introduction of Species |url=http://www.wku.edu/%7Esmithch/wallace/S020.htm |year=1855 |publisher=[[Organization:Western Kentucky University|Western Kentucky University]] |access-date=8 May 2007 |archive-url=https://web.archive.org/web/20070428194531/http://www.wku.edu/~smithch/wallace/S020.htm |archive-date=28 April 2007 |url-status=live}}</ref>

The paper shook Lyell's belief that species were immutable. Although Darwin had written to him in 1842 expressing support for transmutation, Lyell had continued to be strongly opposed to the idea. Around the start of 1856, he told Darwin about Wallace's paper, as did Edward Blyth who thought it "Good! Upon the whole!&nbsp;... Wallace has, I think put the matter well; and according to his theory the various domestic races of animals have been fairly developed into ''species''." Despite this hint, Darwin mistook Wallace's conclusion for the progressive creationism of the time, writing that it was "nothing very new&nbsp;... Uses my simile of tree [but] it seems all creation with him." Lyell was more impressed, and opened a notebook on species in which he grappled with the consequences, particularly for human ancestry. Darwin had already shown his theory to their mutual friend [[Biography:Joseph Dalton Hooker|Joseph Hooker]] and now, for the first time spelt out the full details of natural selection to Lyell. Although Lyell could not agree, he urged Darwin to publish to establish priority. Darwin demurred at first, but began writing up a ''species sketch'' of his continuing work in May 1856.{{sfn|Desmond|Moore|1991|p=438}}{{sfn|Browne|1995|pp=537–546}}

=== Natural selection and Darwin ===

By February 1858, Wallace had been convinced by his biogeographical research in the Malay Archipelago that evolution was real. He later wrote in his autobiography that the problem was of how species change from one well-marked form to another.{{sfn|Wallace|1905a|p=361}} He stated that it was while he was in bed with a fever that he thought about Malthus's idea of positive checks on human population, and had the idea of natural selection. His autobiography says that he was on the island of Ternate at the time; but the evidence of his journal suggests that he was in fact on the island of Gilolo.{{sfn|Slotten|2004|pp=144–145}} From 1858 to 1861, he rented a house on Ternate from the Dutchman Maarten Dirk van Renesse van Duivenbode, which he used as a base for expeditions to other islands such as Gilolo.<ref>{{cite book |last=Heij |first=C. J. |year=2011 |title=Biographical Notes of Antonie Augustus Bruijn (1842–1890) |publisher=IBP Press |place=Bogor |isbn=978-979-493-294-0}}</ref>

Wallace describes how he discovered natural selection as follows:

{{blockquote|It then occurred to me that these causes or their equivalents are continually acting in the case of animals also; and as animals usually breed much more quickly than does mankind, the destruction every year from these causes must be enormous in order to keep down the numbers of each species, since evidently they do not increase regularly from year to year, as otherwise the world would long ago have been crowded with those that breed most quickly. Vaguely thinking over the enormous and constant destruction which this implied, it occurred to me to ask the question, why do some die and some live? And the answer was clearly, on the whole the best fitted live&nbsp;... and considering the amount of individual variation that my experience as a collector had shown me to exist, then it followed that all the changes necessary for the adaptation of the species to the changing conditions would be brought about&nbsp;... In this way every part of an animals organization could be modified exactly as required, and in the very process of this modification the unmodified would die out, and thus the definite characters and the clear isolation of each new species would be explained.{{sfn|Wallace|1905a|pp=361–362}} }}

[[File:Darwin-Wallace medal.jpg|thumb|upright|The Darwin–Wallace Medal was issued by the Linnean Society on the 50th anniversary of the reading of Darwin and Wallace's papers on natural selection. Wallace received the only gold example.<ref>{{Cite web|title=The Darwin-Wallace Medal|url=https://wallacefund.myspecies.info/content/darwin-wallace-medal|website=The Wallace Website}}</ref>|alt=photograph of the Darwin-Wallace medal]]

Wallace had once briefly met Darwin, and was one of the correspondents whose observations Darwin used to support his own theories. Although Wallace's first letter to Darwin has been lost, Wallace carefully kept the letters he received.{{sfn|Marchant|1916|loc=[http://darwin-online.org.uk/content/frameset?itemID=F1593&viewtype=image&pageseq=116 p. 105]}} In the first letter, dated 1 May 1857, Darwin commented that Wallace's letter of 10 October which he had recently received, as well as Wallace's paper "On the Law which has regulated the Introduction of New Species" of 1855, showed that they thought alike, with similar conclusions, and said that he was preparing his own work for publication in about two years time.{{sfn|Darwin|2009|p=[http://darwin-online.org.uk/content/frameset?itemID=F1452.2&viewtype=text&pageseq=111 95]}} The second letter, dated 22 December 1857, said how glad he was that Wallace was theorising about distribution, adding that "without speculation there is no good and original observation" but commented that "I believe I go much further than you".{{sfn|Darwin|2009|p=[http://darwin-online.org.uk/content/frameset?itemID=F1452.2&viewtype=text&pageseq=124 108]}} Wallace believed this and sent Darwin his February 1858 essay, "On the Tendency of Varieties to Depart Indefinitely From the Original Type", asking Darwin to review it and pass it to Charles Lyell if he thought it worthwhile.<ref name="tendency">{{cite web|last=Wallace |first=Alfred |title=On the Tendency of Varieties to Depart Indefinitely From the Original Type |url=http://www.wku.edu/~smithch/wallace/S043.htm |publisher=The Alfred Russel Wallace Page hosted by [[Organization:Western Kentucky University|Western Kentucky University]] |access-date=22 April 2007 |archive-url=https://web.archive.org/web/20070429183411/http://www.wku.edu/~smithch/wallace/S043.htm |archive-date=29 April 2007 |url-status=live}}</ref> Although Wallace had sent several articles for journal publication during his travels through the Malay archipelago, the Ternate essay was in a private letter. Darwin received the essay on 18 June 1858. Although the essay did not use Darwin's term "natural selection", it did outline the mechanics of an evolutionary divergence of species from similar ones due to environmental pressures. In this sense, it was very similar to the theory that Darwin had worked on for 20 years, but had yet to publish. Darwin sent the manuscript to Charles Lyell with a letter saying "he could not have made a better short abstract! Even his terms now stand as heads of my chapters&nbsp;... he does not say he wishes me to publish, but I shall, of course, at once write and offer to send to any journal."{{sfn|Slotten|2004|pp=153–154}}{{sfn|Darwin|2009|loc=[http://darwin-online.org.uk/content/frameset?itemID=F1452.2&viewtype=text&pageseq=132 p. 116]}} Distraught about the illness of his baby son, Darwin put the problem to Charles Lyell and [[Biography:Joseph Dalton Hooker|Joseph Hooker]], who decided to publish the essay in a joint presentation together with unpublished writings which highlighted Darwin's priority. Wallace's essay was presented to the [[Organization:Linnean Society of London|Linnean Society of London]] on 1 July 1858, along with excerpts from an essay which Darwin had disclosed privately to Hooker in 1847 and a letter Darwin had written to Asa Gray in 1857.{{sfn|Browne|2002|pp=33–42}}

Communication with Wallace in the far-off Malay Archipelago involved months of delay, so he was not part of this rapid publication. Wallace accepted the arrangement after the fact, happy that he had been included at all, and never expressed bitterness in public or in private. Darwin's social and scientific status was far greater than Wallace's, and it was unlikely that, without Darwin, Wallace's views on evolution would have been taken seriously. Lyell and Hooker's arrangement relegated Wallace to the position of co-discoverer, and he was not the social equal of Darwin or the other prominent British natural scientists. All the same, the joint reading of their papers on natural selection associated Wallace with the more famous Darwin. This, combined with Darwin's (as well as Hooker's and Lyell's) advocacy on his behalf, would give Wallace greater access to the highest levels of the scientific community.{{sfn|Shermer|2002|pp=148–150}} The reaction to the reading was muted, with the president of the Linnean Society remarking in May 1859 that the year had not been marked by any striking discoveries;{{sfn|Browne|2002|pp=40–42}} but, with Darwin's publication of ''On the Origin of Species'' later in 1859, its significance became apparent. When Wallace returned to the UK, he met Darwin. Although some of Wallace's opinions in the ensuing years would test Darwin's patience, they remained on friendly terms for the rest of Darwin's life.<ref name="Browne 2013">{{cite journal |last1=Browne |first1=Janet |title=Wallace and Darwin |journal=Current Biology |date=2013 |volume=23 |issue=24 |pages=R1071–R1072 |doi=10.1016/j.cub.2013.10.045 |pmid=24501768 |s2cid=4281426 |url=https://www.cell.com/current-biology/pdf/S0960-9822(13)01320-1.pdf}}</ref>

Over the years, a few people have questioned this version of events. In the early 1980s, two books, one by Arnold Brackman and another by John Langdon Brooks, suggested not only that there had been a conspiracy to rob Wallace of his proper credit, but that Darwin had actually stolen a key idea from Wallace to finish his own theory. These claims have been examined and found unconvincing by a number of scholars.{{sfn|Slotten|2004|pp=157–162}}{{sfn|Shermer|2002|loc=[https://web.archive.org/web/20081007080247/http://www.michaelshermer.com/darwins-shadow/excerpt/ Chapter 5: "A Gentlemanly Arrangement: Alfred Russel Wallace, Charles Darwin & the Scientific Priority Dispute"]}}<ref>{{cite web |last=Smith |first=Charles H. |title=Responses to Questions Frequently Asked About Wallace: Did Darwin really steal material from Wallace to complete his theory of natural selection? |url=http://www.wku.edu/~smithch/wallace/FAQ.htm |publisher=The Alfred Russel Wallace Page hosted by [[Organization:Western Kentucky University|Western Kentucky University]] |access-date=29 April 2008| archive-url= https://web.archive.org/web/20080509183747/http://www.wku.edu/~smithch/wallace/FAQ.htm |archive-date=9 May 2008 |url-status=live}}</ref> Shipping schedules show that, contrary to these accusations, Wallace's letter could not have been delivered earlier than the date shown in Darwin's letter to Lyell.<ref>{{cite journal |last1=Wyhe |first1=John Van |last2=Rookmaaker |first2=Kees |year=2012 |title=A new theory to explain the receipt of Wallace's Ternate Essay by Darwin in 1858 |journal=Biological Journal of the Linnean Society |volume=105 |pages=249–252 |doi=10.1111/j.1095-8312.2011.01808.x|doi-access=free }}</ref><ref>{{cite journal |last=Ball |first=Philip |author-link=Philip Ball |title=Shipping timetables debunk Darwin plagiarism accusations |journal=Nature |url=http://www.nature.com/news/shipping-timetables-debunk-darwin-plagiarism-accusations-1.9613 |date=12 December 2011 |doi=10.1038/nature.2011.9613 |s2cid=178946874 }}</ref>

==== Defence of Darwin and his ideas ====

After Wallace returned to England in 1862, he became one of the staunchest defenders of Darwin's ''On the Origin of Species''. In an incident in 1863 that particularly pleased Darwin, Wallace published the short paper "Remarks on the Rev. S. Haughton's Paper on the Bee's Cell, And on the Origin of Species". This rebutted a paper by a professor of geology at the University of Dublin that had sharply criticised Darwin's comments in the ''Origin'' on how hexagonal honey bee cells could have evolved through natural selection.{{sfn|Slotten|2004|pp=197–199}}
An even longer defence was a 1867 article in the ''Quarterly Journal of Science'' called "Creation by Law". It reviewed George Campbell, the 8th Duke of Argyll's book, ''The Reign of Law'', which aimed to refute natural selection.<ref>{{cite web |last=Wallace |first=Alfred |title=Creation by Law (S140: 1867) |url=http://www.wku.edu/~smithch/wallace/S140.htm |publisher=The Alfred Russel Wallace Page hosted by [[Organization:Western Kentucky University|Western Kentucky University]] |access-date=23 May 2007 |archive-url= https://web.archive.org/web/20070602121908/http://www.wku.edu/~smithch/wallace/S140.htm |archive-date= 2 June 2007 |url-status=live }}</ref>
After an 1870 meeting of the [[Organization:British Science Association|British Science Association]], Wallace wrote to Darwin complaining that there were "no opponents left who know anything of natural history, so that there are none of the good discussions we used to have."{{sfn|Slotten|2004|p=261}}

==== Differences between Darwin's and Wallace's ideas on natural selection ====

Historians of science have noted that, while Darwin considered the ideas in Wallace's paper to be essentially the same as his own, there were differences.<ref>{{Cite journal |last=Kutschera |first=Ulrich |title=A comparative analysis of the Darwin–Wallace papers and the development of the concept of natural selection |journal=Theory in Biosciences |date=19 December 2003 |doi=10.1007/s12064-003-0063-6 |volume=122 |issue=4 |pages=343–59 |s2cid=24297627 }}</ref> Darwin emphasised competition between individuals of the same species to survive and reproduce, whereas Wallace emphasised environmental pressures on varieties and species forcing them to become adapted to their local conditions, leading populations in different locations to diverge.{{sfn|Larson|2004|p=75}}{{sfn|Bowler|Morus|2005|p=149}} The historian of science [[Biography:Peter J. Bowler|Peter J. Bowler]] has suggested that in the paper he mailed to Darwin, Wallace might have been discussing [[Biology:Group selection|group selection]].{{sfn|Bowler|2013|pp=61–63}} Against this, Malcolm Kottler showed that Wallace was indeed discussing individual variation and selection.<ref>{{cite book |last=Kottler |first=Malcolm |year=1985 |chapter=Charles Darwin and Alfred Russel Wallace: Two decades of debate over natural selection |editor-last=Kohn |editor-first=David Kohn |title=The Darwinian Heritage |publisher=Princeton University Press |pages=367–432 |isbn=978-0691083568 }}</ref>

Others have noted that Wallace appeared to have envisioned natural selection as a kind of feedback mechanism that kept species and varieties adapted to their environment (now called 'stabilizing", as opposed to 'directional' selection).<ref name="Unfinished Business"/> They point to a largely overlooked passage of Wallace's famous 1858 paper, in which he likened "this principle ... [to] the [[Centrifugal governor|centrifugal governor]] of the steam engine, which checks and corrects any irregularities".<ref name="tendency"/> The [[Cybernetics|cybernetician]] and anthropologist [[Biography:Gregory Bateson|Gregory Bateson]] observed in the 1970s that, although writing it only as an example, Wallace had "probably said the most powerful thing that'd been said in the 19th Century".<ref>{{cite web |last=Brand |first=Stewart |title=For God's Sake, Margaret |url=http://www.oikos.org/forgod.htm |publisher=CoEvolutionary Quarterly, June 1976 |access-date=4 April 2007 |archive-url=https://web.archive.org/web/20070415185352/http://www.oikos.org/forgod.htm |archive-date=15 April 2007 |url-status=dead}}</ref> Bateson revisited the topic in his 1979 book ''Mind and Nature: A Necessary Unity'', and other scholars have continued to explore the connection between natural selection and [[Systems theory|systems theory]].<ref name="Unfinished Business">{{cite journal |last=Smith |first=Charles H. |title=Wallace's Unfinished Business |url=http://www.wku.edu/~smithch/essays/UNFIN.htm |journal=Complexity |volume=10 |issue=2 |date=2004}}</ref>

==== Warning coloration and sexual selection ====
{{further|Biology:The Colours of Animals}}

[[File:Darwinism 1889 Fig. 26 image of mimicry.jpg|thumb|upright|Illustration of [[Biology:Batesian mimicry|Batesian mimicry]]: a wasp (top) mimicked by a beetle in Wallace's 1889 book ''Darwinism'']]

[[Earth:Aposematism|Warning coloration]]<!--Brit. usage is colour, but coloration, see [[Physics:Structural coloration|structural coloration]] for detailed explanation--> was one of Wallace's contributions to the evolutionary biology of animal coloration.{{sfn|Slotten|2004|pp=251–254}} In 1867, Darwin wrote to Wallace about a problem in explaining how some caterpillars could have evolved conspicuous colour schemes. Darwin had come to believe that many conspicuous animal colour schemes were due to sexual selection, but he saw that this could not apply to caterpillars. Wallace responded that he and Bates had observed that many of the most spectacular butterflies had a peculiar odour and taste, and that he had been told by [[Biography:John Jenner Weir|John Jenner Weir]] that birds would not eat a certain kind of common white moth because they found it unpalatable. Since the moth was as conspicuous at dusk as a coloured caterpillar in daylight, it seemed likely that the conspicuous colours served as a warning to predators and thus could have evolved through natural selection. Darwin was impressed by the idea. At a later meeting of the Entomological Society, Wallace asked for any evidence anyone might have on the topic.<ref>{{Cite journal |last=Smith |first=Frederick |date=1867 |title=March 4, 1867 |journal=Transactions of the Royal Entomological Society of London |volume=15 |issue=7 |pages=509–566 |doi=10.1111/j.1365-2311.1967.tb01466.x}}</ref> In 1869, Weir published data from experiments and observations involving brightly coloured caterpillars that supported Wallace's idea.{{sfn|Slotten|2004|pp=253-254}}<!--mentioned also in Wallace's ''Darwinism'', ch. 9, and in [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F1548.1&pageseq=322 a letter by Darwin to A. Weismann on 1 May 1875]--> Wallace attributed less importance than Darwin to sexual selection. In his 1878 book ''Tropical Nature and Other Essays'', he wrote extensively about the [[Biology:Animal coloration|coloration of animals]] and plants, and proposed alternative explanations for a number of cases Darwin had attributed to sexual selection.{{sfn|Slotten|2004|pp=353–356}} He revisited the topic at length in his 1889 book ''Darwinism''. In 1890, he wrote a critical review in ''Nature'' of his friend [[Biography:Edward Bagnall Poulton|Edward Bagnall Poulton]]'s ''[[Biology:The Colours of Animals|The Colours of Animals]]'' which supported Darwin on sexual selection, attacking especially Poulton's claims on the "aesthetic preferences of the insect world".<ref>{{cite journal |last=Wallace |first=Alfred Russel |title=[Review] The Colours of Animals |journal=Nature |volume=42 |pages=289–291 |date=24 July 1890 |issue=1082 |doi=10.1038/042289a0 |bibcode=1890Natur..42..289W |s2cid=27117910 |url=https://zenodo.org/record/1429319 }}</ref><ref name="Nature">{{cite web |url=https://people.wku.edu/charles.smith/wallace/S424.htm | title=The Colours of Animals |last=Wallace |first=Alfred Russel |website=The Alfred Russel Wallace Page |access-date=25 May 2022 }}</ref>

==== Wallace effect ====
{{further|Biology:Reinforcement (speciation)}}

In 1889, Wallace wrote the book ''Darwinism'', which explained and defended natural selection. In it, he proposed the hypothesis that natural selection could drive the reproductive isolation of two varieties by encouraging the development of barriers against hybridisation. Thus it might contribute to the development of new species. He suggested the following scenario: When two populations of a species had diverged beyond a certain point, each adapted to particular conditions, hybrid offspring would be less adapted than either parent form and so natural selection would tend to eliminate the hybrids. Furthermore, under such conditions, natural selection would favour the development of barriers to hybridisation, as individuals that avoided hybrid matings would tend to have more fit offspring, and thus contribute to the reproductive isolation of the two incipient species. This idea came to be known as the [[Biology:Reinforcement (speciation)|Wallace effect]],{{sfn|Wallace|1889|pp=174–179, 353}}{{sfn|Slotten|2004|pp=413–415}} later called reinforcement.<ref name="Speciation">{{cite book |last1=Coyne |first1=Jerry |last2=Orr |first2=H. Allen | title=Speciation | date=2004 | pages=353–381 | publisher=Sinauer Associates | isbn=978-0-87893-091-3 }}</ref> Wallace had suggested to Darwin that natural selection could play a role in preventing hybridisation in private correspondence as early as 1868, but had not worked it out to this level of detail.{{sfn|Slotten|2004|p=404}} It continues to be a topic of research in evolutionary biology today, with both computer simulation and empirical results supporting its validity.<ref>{{cite journal |last=Ollerton |first=J. |title=Speciation: Flowering time and the Wallace Effect |journal=Heredity |date=September 2005 |volume=95 |issue=3 |pages=181–182 |pmid=16077739 |doi=10.1038/sj.hdy.6800718 |s2cid=13300641}}</ref>

=== Application of theory to humans, and role of teleology in evolution ===
[[File:Wallace chimp.jpg|thumb|left|upright|An illustration from the chapter on the application of natural selection to humans in Wallace's 1889 book ''Darwinism'' shows a chimpanzee.|alt=illustration of a chimpanzee from one of Wallace's books]]

In 1864, Wallace published a paper, "The Origin of Human Races and the Antiquity of Man Deduced from the Theory of 'Natural Selection{{' "}}, applying the theory to humankind. Darwin had not yet publicly addressed the subject, although Thomas Huxley had in ''Evidence as to Man's Place in Nature''. Wallace explained the apparent stability of the human stock by pointing to the vast gap in cranial capacities between humans and the [[Biology:Hominidae|great apes]]. Unlike some other Darwinists, including Darwin himself, he did not "regard modern primitives as almost filling the gap between man and ape".<ref name=eiseley>{{cite book |last=Eiseley |first=Loren |title=Darwin's Century |publisher=Anchor Books |year=1958 |pages=305–306}}</ref> He saw the evolution of humans in two stages: achieving a bipedal posture that freed the hands to carry out the dictates of the brain, and the "recognition of the human brain as a totally new factor in the history of life".<ref name=eiseley/> Wallace seems to have been the first evolutionist to see that the human brain effectively made further specialisation of the body unnecessary.<ref name=eiseley/> Wallace wrote the paper for the Anthropological Society of London to address the debate between the supporters of [[Biology:Monogenism|monogenism]], the belief that all human races shared a common ancestor and were one species, and the supporters of [[Social:Polygenism|polygenism]], who held that different races had separate origins and were different species. Wallace's anthropological observations of native Americans in the Amazon, and especially his time living among the Dayak people of Borneo, had convinced him that human beings were a single species with a common ancestor. He still felt that natural selection might have continued to act on mental faculties after the development of the different races; and he did not dispute the nearly universal view among European anthropologists of the time that Europeans were intellectually superior to other races.{{sfn|Slotten|2004|pp=207–213}}{{sfn|Shermer|2002|pp=218–221}} 

Shortly afterwards, Wallace became a [[Unsolved:Spiritualism|spiritualist]]. At about the same time, he began to maintain that natural selection could not account for mathematical, artistic, or musical genius, metaphysical musings, or wit and humour. He stated that something in "the unseen universe of Spirit" had interceded at least three times in history: the creation of life from inorganic matter; the introduction of consciousness in the higher animals; and the generation of the higher mental faculties in humankind. He believed that the raison d'être of the universe was the development of the human spirit.{{sfn|Wallace|1889|p=477}} 

While some historians have concluded that Wallace's belief that natural selection was insufficient to explain the development of consciousness and the higher functions of the human mind was directly caused by his adoption of spiritualism, other scholars have disagreed, and some maintain that Wallace never believed natural selection applied to those areas.{{sfn|Shermer|2002|pp=157–160}}<ref>{{cite web |last=Smith |first=Charles H. |title=Alfred Russel Wallace: Evolution of an Evolutionist Chapter Six. A Change of Mind? |url=http://www.wku.edu/~smithch/wallace/chsarw6.htm |publisher=[[Organization:Western Kentucky University|Western Kentucky University]] |access-date=29 April 2007}}</ref> Reaction to Wallace's ideas on this topic among leading naturalists at the time varied. Lyell endorsed Wallace's views on human evolution rather than Darwin's.{{sfn|Larson|2004|p=100}}{{sfn|Shermer|2002|p=160}} Wallace's belief that human consciousness could not be entirely a product of purely material causes was shared by a number of prominent intellectuals in the late 19th and early 20th centuries.<ref name="Shermer231">{{harvnb|Shermer|2002|pp=231–233}}</ref> All the same, many, including Huxley, Hooker, and Darwin himself, were critical of Wallace.{{sfn|Slotten|2004|pp=280–296}}

As the historian of science and sceptic [[Biography:Michael Shermer|Michael Shermer]] has stated, Wallace's views in this area were at odds with two major tenets of the emerging Darwinian philosophy. These were that evolution was not teleological (purpose driven), and that it was not anthropocentric (human-centred).{{sfn|Shermer|2002|pp=208–209}} Much later in his life Wallace returned to these themes, that evolution suggested that the universe might have a purpose, and that certain aspects of living organisms might not be explainable in terms of purely materialistic processes. He set out his ideas in a 1909 magazine article entitled ''The World of Life'', later expanded into a book of the same name.<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S669.htm |title=The World of Life: As Visualised and Interpreted by Darwinism (S669: 1909) |last=Wallace |first=Alfred Russel |publisher=[[Organization:Western Kentucky University|Western Kentucky University]] |access-date=25 May 2022}}</ref> Shermer commented that this anticipated ideas about design in nature and directed evolution that would arise from religious traditions throughout the 20th century.<ref name="Shermer231"/>

=== Assessment of Wallace's role in history of evolutionary theory ===

In many accounts of the development of evolutionary theory, Wallace is mentioned only in passing as simply being the stimulus to the publication of Darwin's own theory.<ref name="Slotten_p6">{{harvnb|Slotten|2004|p=6}}</ref> In reality, Wallace developed his own distinct evolutionary views which diverged from Darwin's, and was considered by many (especially Darwin) to be a leading thinker on evolution in his day, whose ideas could not be ignored. One historian of science has pointed out that, through both private correspondence and published works, Darwin and Wallace exchanged knowledge and stimulated each other's ideas and theories over an extended period.{{sfn|Shermer|2002|p=149}} Wallace is the most-cited naturalist in Darwin's ''Descent of Man'', occasionally in strong disagreement.{{sfn|Slotten|2004|pp=289–290}} Darwin and Wallace agreed on the importance of natural selection, and some of the factors responsible for it: competition between species and geographical isolation. But Wallace believed that evolution had a purpose ("teleology") in maintaining species' fitness to their environment, whereas Darwin hesitated to attribute any purpose to a random natural process. Scientific discoveries since the 19th century support Darwin's viewpoint, by identifying additional mechanisms and triggers such as mutations triggered by environmental radiation or mutagenic chemicals.<ref name="Hamilton 2008">{{cite magazine  |last=Hamilton |first=Garry |title=Viruses: The unsung heroes of evolution |magazine=New Scientist |date=27 August 2008 |url=https://www.newscientist.com/article/mg19926711-600-viruses-the-unsung-heroes-of-evolution}}</ref> Wallace remained an ardent defender of natural selection for the rest of his life. By the 1880s, evolution was widely accepted in scientific circles, but natural selection less so. Wallace's 1889 ''Darwinism'' was a response to the scientific critics of natural selection.{{sfn|Slotten|2004|p=409}} Of all Wallace's books, it is the most cited by scholarly publications.{{sfn|Shermer|2002|p=18}}

== Other scientific contributions ==

=== Biogeography and ecology ===
[[File:Wallace03.jpg|thumb|upright=1.5|A map of the world from ''The Geographical Distribution of Animals'' shows Wallace's six biogeographical regions.|alt=map of the world divided into Wallace's six biogeographical regions]]

In 1872, at the urging of many of his friends, including Darwin, Philip Sclater, and [[Biography:Alfred Newton|Alfred Newton]], Wallace began research for a general review of the geographic distribution of animals. Initial progress was slow, in part because classification systems for many types of animals were in flux.{{sfn|Slotten|2004|p=301}} He resumed the work in earnest in 1874 after the publication of a number of new works on classification.{{sfn|Slotten|2004|p=315}} Extending the system developed by Sclater for birds—which divided the earth into six separate geographic regions for describing species distribution—to cover mammals, reptiles and insects as well, Wallace created the basis for the [[Biology:Biogeographic realm|zoogeographic regions]] in use today. He discussed the factors then known to influence the current and past geographic distribution of animals within each geographic region.<ref name="Holt Lessard Borregaard 2013">{{cite journal |last1=Holt |first1=Ben G. |last2=Lessard |first2=Jean-Philippe |last3=Borregaard |first3=Michael K. |last4=Fritz |first4=Susanne A. |last5=Araújo |first5=Miguel B. |last6=Dimitrov |first6=Dimitar |last7=Fabre |first7=Pierre-Henri |last8=Graham |first8=Catherine H. |last9=Graves |first9=Gary R. |last10=Jønsson |first10=Knud A. |last11=Nogués-Bravo |first11=David |last12=Wang |first12=Zhiheng |last13=Whittaker |first13=Robert J. |last14=Fjeldså |first14=Jon |last15=Rahbek |first15=Carsten |display-authors=3 |title=An Update of Wallace's Zoogeographic Regions of the World |journal=Science |volume=339 |issue=6115 |date=4 January 2013 |doi=10.1126/science.1228282 |pages=74–78|pmid=23258408 |bibcode=2013Sci...339...74H |s2cid=1723657 }}</ref>

These factors included the effects of the appearance and disappearance of land bridges (such as the one currently [[Earth:Great American Interchange|connecting North America and South America]]) and the effects of periods of increased glaciation. He provided maps showing factors, such as elevation of mountains, depths of oceans, and the character of regional vegetation, that affected the distribution of animals. He summarised all the known families and genera of the higher animals and listed their known geographic distributions. The text was organised so that it would be easy for a traveller to learn what animals could be found in a particular location. The resulting two-volume work, ''The Geographical Distribution of Animals'', was published in 1876 and served as the definitive text on [[Biology:Zoogeography|zoogeography]] for the next 80 years.{{sfn|Slotten|2004|pp=320–325}}

The book included evidence from the fossil record to discuss the processes of evolution and migration that had led to the geographical distribution of modern species. For example, he discussed how fossil evidence showed that tapirs had originated in the [[Earth:Northern Hemisphere|Northern Hemisphere]], migrating between North America and Eurasia and then, much more recently, to South America after which the northern species became extinct, leaving the modern distribution of two isolated groups of tapir species in South America and Southeast Asia.{{sfn|Bowler|2013|p=152}} Wallace was very aware of, and interested in, the [[Earth:Quaternary extinction event|mass extinction of megafauna]] in the late [[Earth:Pleistocene|Pleistocene]]. In ''The Geographical Distribution of Animals'' (1876) he wrote, "We live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared".{{sfn|Wallace|1876|p=150}} He added that he believed the most likely cause for the rapid extinctions was glaciation, but by the time he wrote ''World of Life'' (1911) he had come to believe those extinctions were "due to man's agency".{{sfn|Wallace|1911|p=264}}

[[File:Wallace-line1.jpg|thumb|left|upright=1.7|The line separating the Indo-Malayan and the Austro-Malayan region in Wallace's ''On the Physical Geography of the Malay Archipelago'' (1863)|alt=map of Southeast Asia showing the Wallace line]]

In 1880, Wallace published the book ''Island Life'' as a sequel to ''The Geographical Distribution of Animals''. It surveyed the distribution of both animal and plant species on islands. Wallace classified islands into oceanic and two types of continental islands. Oceanic islands, in his view, such as the Galapagos and [[Earth:Hawaiian Islands|Hawaiian Islands]] (then called Sandwich Islands) formed in mid-ocean and never part of any large continent. Such islands were characterised by a complete lack of terrestrial mammals and amphibians, and their inhabitants (except migratory birds and species introduced by humans) were typically the result of accidental colonisation and subsequent evolution. Continental islands, in his scheme, were divided into those that were recently separated from a continent (like Britain) and those much less recently (like {{wipe|Madagascar}}). Wallace discussed how that difference affected flora and fauna. He discussed how isolation affected evolution and how that could result in the preservation of classes of animals, such as the lemurs of Madagascar that were remnants of once widespread continental faunas. He extensively discussed how changes of climate, particularly periods of increased glaciation, may have affected the distribution of flora and fauna on some islands, and the first portion of the book discusses possible causes of these great [[Earth:Ice age|ice age]]s. ''Island Life'' was considered a very important work at the time of its publication. It was discussed extensively in scientific circles both in published reviews and in private correspondence.{{sfn|Slotten|2004|p=361}}

=== Environmentalism ===

Wallace's extensive work in biogeography made him aware of the impact of human activities on the natural world. In ''Tropical Nature and Other Essays'' (1878), he warned about the dangers of deforestation and soil erosion, especially in tropical climates prone to heavy rainfall. Noting the complex interactions between vegetation and climate, he warned that the extensive clearing of [[Earth:Rainforest|rainforest]] for coffee cultivation in Ceylon (now called Sri Lanka) and India would adversely impact the climate in those countries and lead to their impoverishment due to soil erosion.{{sfn|Slotten|2004|p=352–353}} In ''Island Life'', Wallace again mentioned deforestation and [[Earth:Invasive species|invasive species]]. On the impact of European colonisation on the island of Saint Helena, he wrote that the island was "now so barren and forbidding that some persons find it difficult to believe that it was once all green and fertile".{{sfn|Wallace|1881|pp=283–284}}  He explained that the soil was protected by the island's vegetation; once that was destroyed, the soil was washed off the steep slopes by heavy tropical rain, leaving "bare rock or sterile clay".{{sfn|Wallace|1881|pp=283–284}} He attributed the "irreparable destruction"{{sfn|Wallace|1881|pp=283–284}}  to feral goats, introduced in 1513. The island's forests were further damaged by the "reckless waste"{{sfn|Wallace|1881|pp=283–284}}  of the East India Company from 1651, which used the bark of valuable redwood and ebony trees for tanning, leaving the wood to rot unused.{{sfn|Wallace|1881|pp=283–284}} Wallace's comments on environment grew more urgent later in his career. In ''The World of Life'' (1911) he wrote that people should view nature "as invested with a certain sanctity, to be used by us but not abused, and never to be recklessly destroyed or defaced."{{sfn|Wallace|1911|p=279}}

=== Astrobiology ===

Wallace's 1904 book ''Man's Place in the Universe'' was the first serious attempt by a biologist to evaluate the [[Astronomy:Planetary habitability|likelihood of life on other planets]]. He concluded that the Earth was the only planet in the solar system that could possibly support life, mainly because it was the only one in which water could exist in the liquid phase.<ref name="Kutschera 2012">{{cite journal |last=Kutschera |first=Ulrich |title=Wallace pioneered astrobiology too |journal=Nature |volume=489 |issue=7415 |year=2012 |doi=10.1038/489208e |pages=208 |pmid=22972286 |s2cid=4333070 }}</ref> His treatment of [[Astronomy:Mars|Mars]] in this book was brief, and in 1907, Wallace returned to the subject with a book ''Is Mars Habitable?'' to criticise the claims made by the American astronomer [[Biography:Percival Lowell|Percival Lowell]] that there were [[Astronomy:Martian canals|Martian canals]] built by intelligent beings. Wallace did months of research, consulted various experts, and produced his own scientific analysis of the Martian climate and atmospheric conditions.{{sfn|Slotten|2004|p=474}} He pointed out that spectroscopic analysis had shown no signs of water vapour in the Martian atmosphere, that Lowell's analysis of Mars's climate badly overestimated the surface temperature, and that low atmospheric pressure would make liquid water, let alone a planet-girding irrigation system, impossible.<ref>{{cite web|last=Wallace|first=Alfred|title=''Is Mars Habitable'' (S730: 1907)|url=http://www.wku.edu/~smithch/wallace/S730.htm|publisher=The Alfred Russel Wallace Page hosted by [[Organization:Western Kentucky University|Western Kentucky University]]|access-date=13 May 2007|archive-url= https://web.archive.org/web/20070405172431/http://www.wku.edu/~smithch/wallace/S730.htm|archive-date= 5 April 2007 |url-status=live}}</ref> Richard Milner comments that Wallace "effectively debunked Lowell's illusionary network of Martian canals."<ref>{{cite web|title=A Wet Red World? The Search for Water on Mars Goes On|author=Richard Milner|publisher=Astrobiology Magazine|date=4 November 2011|url=http://www.space.com/13510-water-mars-search-life.html|access-date=22 November 2012}}</ref> Wallace became interested in the topic because his anthropocentric philosophy inclined him to believe that man would be unique in the universe.{{sfn|Shermer|2002|p=294}}

== Other activities ==

<!--=== Poetry ===

Wallace included metrical verse such as his "A Description of Javíta" in his book ''Travels on the Amazon''. <ref>''Travels on the Amazon'' (1889 ed.), [https://archive.org/details/travelsonamazon00wall_0/page/176/mode/2up pp. 176–180]</ref>-->

=== Spiritualism<!--linked from 'Spiritualism (philosophy)'--> ===

Wallace was an enthusiast of [[Philosophy:Phrenology|phrenology]].{{sfn|Slotten|2004|p=203–205}} Early in his career, he experimented with [[Unsolved:Hypnosis|hypnosis]], then known as mesmerism, managing to hypnotise some of his students in Leicester.{{sfn|Slotten|2004|p=234–235}} When he began these experiments, the topic was very controversial: early experimenters, such as John Elliotson, had been harshly criticised by the medical and scientific establishment.<ref name="Belief and Spiritualism">{{cite web |last=Smith |first=Charles H. |title=Alfred Russel Wallace: Evolution of an Evolutionist Chapter One. Belief and Spiritualism |url=http://www.wku.edu/~smithch/wallace/chsarw1.htm |publisher=The Alfred Russel Wallace Page hosted by [[Organization:Western Kentucky University|Western Kentucky University]] |access-date=20 April 2007}}</ref> Wallace drew a connection between his experiences with mesmerism and spiritualism, arguing that one should not deny observations on "a priori grounds of absurdity or impossibility".<ref>{{cite web |last=Wallace |first=Alfred |title=Notes on the Growth of Opinion as to Obscure Psychical Phenomena During the Last Fifty Years |url=http://www.wku.edu/~smithch/wallace/S478.htm |publisher=[[Organization:Western Kentucky University|Western Kentucky University]] |access-date=20 April 2007}}</ref>

[[File:Wallace Spirit Photograph.png|thumb|upright|[[Spirit photography|Spirit photograph]] taken by Frederick Hudson of Wallace and his late mother in 1882; he may have used [[Multiple exposure|double exposure]].|alt=a purported spirit photograph of Wallace and his late mother as if together]]

Wallace began investigating spiritualism in the summer of 1865, possibly at the urging of his older sister Fanny Sims.{{sfn|Slotten|2004|p=231}} After reviewing the literature and attempting to test what he witnessed at [[Unsolved:Séance|séance]]s, he came to believe in it. For the rest of his life, he remained convinced that at least some séance phenomena were genuine, despite accusations of fraud and evidence of trickery. One biographer suggested that the emotional shock  when his first fiancée broke their engagement contributed to his receptiveness to spiritualism.{{sfn|Slotten|2004|p=236}} Other scholars have emphasised his desire to find scientific explanations for all phenomena.<ref name="Belief and Spiritualism"/><ref name="Shermer199201">{{harvnb|Shermer|2002|pp=199–201}}</ref> In 1874, Wallace visited the spirit photographer Frederick Hudson. He declared that a photograph of him with his deceased mother was genuine.{{sfn|Wallace|1875|pp=190–191}} Others reached a different conclusion: Hudson's photographs had previously been exposed as fraudulent in 1872.<ref>{{cite book |last=McCabe |first=Joseph |year=1920 |title=Spiritualism: A Popular History from 1847 |publisher=Dodd, Mead and Company |page=157 |oclc=2683858 }}</ref>

Wallace's public advocacy of spiritualism and his repeated defence of spiritualist mediums against allegations of fraud in the 1870s damaged his scientific reputation. In 1875 he published the evidence he believed proved his position in ''On Miracles and Modern Spiritualism''.{{sfn|Wallace|1875|p=v}} His attitude permanently strained his relationships with previously friendly scientists such as [[Biography:Henry Walter Bates|Henry Bates]], Thomas Huxley, and even Darwin.<ref>{{cite web |url=http://www.nhm.ac.uk/research-curation/scientific-resources/collections/library-collections/wallace-letters-online/index.html |title=Wallace Letters Online |last=Wallace |first=Alfred Russel |date=16 November 2010 |website=The Alfred Russel Wallace Correspondence Project}} See Wallace's letters dated 22 November and 1 December 1866 to Thomas Huxley, and Huxley's reply that he was not interested.</ref>{{sfn|Slotten|2004|pp=298–351}} Others, such as the physiologist [[Biography:William Benjamin Carpenter|William Benjamin Carpenter]] and zoologist E. Ray Lankester became publicly hostile to Wallace over the issue. Wallace was heavily criticised by the press; ''The Lancet'' was particularly harsh.{{sfn|Slotten|2004|pp=298–351}} When, in 1879, Darwin first tried to rally support among naturalists to get a civil pension awarded to Wallace, [[Biography:Joseph Dalton Hooker|Joseph Hooker]] responded that "Wallace has lost caste considerably, not only by his adhesion to Spiritualism, but by the fact of his having deliberately and against the whole voice of the committee of his section of the British Association, brought about a discussion on Spiritualism at one of its sectional meetings&nbsp;... This he is said to have done in an underhanded manner, and I well remember the indignation it gave rise to in the B.A. Council."{{sfn|Slotten|2004|pp=357–358}}{{sfn|Shermer|2002|p=274}} Hooker eventually relented and agreed to support the pension request.{{sfn|Slotten|2004|p=362}}

=== Flat Earth wager ===

In 1870, a [[Astronomy:Flat Earth|flat-Earth]] proponent named John Hampden offered a £500 wager (roughly {{inflation|UK|500|1870|r=-3|fmt=eq|cursign=£}}{{inflation-fn|UK}}) in a magazine advertisement to anyone who could demonstrate a convex curvature in a body of water such as a river, canal, or lake. Wallace, intrigued by the challenge and short of money at the time, designed an experiment in which he set up two objects along a {{convert|6|mi|km|spell=in|adj=on|0}} stretch of canal. Both objects were at the same height above the water, and he mounted a telescope on a bridge at the same height above the water as well. When seen through the telescope, one object appeared higher than the other, showing the curvature of the earth. The judge for the wager, the editor of ''Field'' magazine, declared Wallace the winner, but Hampden refused to accept the result. He sued Wallace and launched a campaign, which persisted for several years, of writing letters to various publications and to organisations of which Wallace was a member denouncing him as a swindler and a thief. Wallace won multiple libel suits against Hampden, but the resulting litigation cost Wallace more than the amount of the wager, and the controversy frustrated him for years.{{sfn|Shermer|2002|pp=258–261}}

=== Anti-vaccination campaign ===

In the early 1880s, Wallace joined the debate over mandatory smallpox [[Biology:Vaccination|vaccination]]. Wallace originally saw the issue as a matter of personal liberty; but, after studying statistics provided by anti-vaccination activists, he began to question the efficacy of vaccination. At the time, the [[Biology:Germ theory of disease|germ theory of disease]] was new and far from universally accepted. Moreover, no one knew enough about the human [[Biology:Immune system|immune system]] to understand why vaccination worked. Wallace discovered instances where supporters of vaccination had used questionable, in a few cases completely false, statistics to support their arguments. Always suspicious of authority, Wallace suspected that physicians had a vested interest in promoting vaccination, and became convinced that reductions in the incidence of smallpox that had been attributed to vaccination were due to better hygiene and improvements in public sanitation.<ref name="Slotten422-436">{{harvnb|Slotten|2004|pp=422–436}}</ref>

Another factor in Wallace's thinking was his belief that, because of the action of natural selection, organisms were in a state of balance with their environment, and that everything in nature, even disease-causing organisms, served a useful purpose; he feared vaccination might upset this balance.<ref name="Shermer215"/> Wallace pointed out that vaccination, which at the time was often unsanitary, could be dangerous.<ref name="Shermer215">{{harvnb|Shermer|2002|pp= 215–216}}</ref>

In 1890, Wallace gave evidence to a Royal Commission investigating the controversy. It found errors in his testimony, including some questionable statistics. ''The Lancet'' averred that Wallace and other activists were being selective in their choice of statistics. The commission found that smallpox vaccination was effective and should remain compulsory, though they recommended some changes in procedures to improve safety, and that the penalties for people who refused to comply be made less severe. Years later, in 1898, Wallace wrote a pamphlet, ''Vaccination a Delusion; Its Penal Enforcement a Crime'', attacking the commission's findings. It, in turn, was attacked by ''The Lancet'', which stated that it repeated many of the same errors as his evidence given to the commission.<ref name="Slotten422-436"/>

== Legacy and historical perception ==
=== Honours ===
[[File:Alfred Russel Wallace - Project Gutenberg eText 14558.jpg|thumb|left|upright|Wallace and his signature on the frontispiece of ''Darwinism'' (1889)|alt=frontispiece of one of Wallace's books]]

As a result of his writing, Wallace became a well-known figure both as a scientist and as a social activist, and was often sought out for his views.{{sfn|Shermer|2002|pp=292–294}} He became president of the anthropology section of the British Association in 1866,<ref>{{cite web |url=https://people.wku.edu/charles.smith/wallace/S120.htm|title=Anthropology at the British Association (S120: 1866) |last=Wallace |first=Alfred Russel |website=The Alfred Russel Wallace Page |access-date=25 May 2022}}</ref> and of the Entomological Society of London in 1870.<ref name=eb1911/> He was elected to the American Philosophical Society in 1873.<ref>{{Cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?year=1873;year-max=1873;smode=advanced;f1-mem=International |access-date=12 September 2022 |website=search.amphilsoc.org |url-status=live |archive-url=https://web.archive.org/web/20210501233158/https://search.amphilsoc.org/memhist/search?year=1873;year-max=1873;smode=advanced;f1-mem=International |archive-date=1 May 2021}}</ref> The British Association elected him as head of its biology section in 1876.<ref name="chronology">{{cite web |title=Chronology of the Main Events in Wallace's Life |url=http://people.wku.edu/charles.smith/wallace/chronol.htm |publisher=The Alfred Russel Wallace Page |access-date=5 December 2015}}</ref> He was elected to the Royal Society in 1893.<ref name="chronology"/> He was asked to chair the International Congress of Spiritualists meeting in London in 1898.{{sfn|Slotten|2004|p=454}} He received honorary doctorates and professional honours, such the Royal Society's Royal Medal in 1868 and its Darwin Medal in 1890,<ref name=eb1911>{{cite EB1911 |wstitle=Wallace, Alfred Russel}}</ref> and the Order of Merit in 1908.<ref>{{London Gazette |issue=28194 |supp=y |page=8162 |date=9 November 1908}}</ref>

=== Obscurity and rehabilitation ===

Wallace's fame faded quickly after his death. For a long time, he was treated as a relatively obscure figure in the history of science.<ref name="Slotten_p6"/> Reasons for this lack of attention may have included his modesty, his willingness to champion unpopular causes without regard for his own reputation, and the discomfort of much of the scientific community with some of his unconventional ideas.<ref name="Laserna">{{cite book |last=Laserna |first=David Blanco |date=2016 |title=La evolución, el fenómeno más complejo del universo |trans-title=Evolution, the most complex process of the universe |language=Spanish |publisher=RBA |isbn=978-84-473-8675-8 |page=11}}</ref> The reason that the theory of evolution is popularly credited to Darwin is likely the impact of Darwin's ''On the Origin of Species''.<ref name="Laserna"/>

Recently, Wallace has become better-known, with the publication of at least five book-length biographies and two anthologies of his writings published since 2000.<ref>{{cite web |last=Rosen |first=Jonathan |title=Missing Link: Alfred Russel Wallace, Charles Darwin's neglected double |date=4 February 2007 |url=https://www.newyorker.com/arts/critics/atlarge/2007/02/12/070212crat_atlarge_rosen |publisher=The New Yorker Feb 2007|access-date=25 April 2007}}</ref> A web page dedicated to Wallace scholarship is maintained at [[Organization:Western Kentucky University|Western Kentucky University]].<ref>{{cite web |title=The Alfred Russel Wallace Page |url=http://www.wku.edu/~smithch/index1.htm |publisher=hosted by Western Kentucky University |access-date=13 May 2007 | archive-url= https://web.archive.org/web/20070523065328/http://www.wku.edu/~smithch/index1.htm| archive-date= 23 May 2007 |url-status=live}}</ref>
In a 2010 book, the environmentalist [[Biography:Tim Flannery|Tim Flannery]] argued that Wallace was "the first modern scientist to comprehend how essential cooperation is to our survival", and suggested that Wallace's understanding of natural selection and his later work on the atmosphere should be seen as a forerunner to modern ecological thinking.{{sfn|Flannery|2010|p=32}} A collection of his medals, including the Order of Merit, were sold at auction for £273,000 in 2022.<ref>{{cite news |first=Nick |last=Hartland |title=Evolution guru's medals auctioned for £273,000 |publisher=Monmouthshire Beacon |page=9 |date=10 August 2022 }}</ref> 

=== Centenary celebrations ===


[[File:Bronze statue of Alfred Russel Wallace.jpg|thumb|upright|Anthony Smith's statue of Wallace, looking up at a bronze model of a Wallace's golden birdwing butterfly. Natural History Museum, London, unveiled 7 November 2013.|alt=photograph of a statue of Wallace in London]]

The [[Biology:Natural History Museum, London|Natural History Museum]], London, co-ordinated commemorative events for the Wallace centenary worldwide in the 'Wallace100' project in 2013.<ref>{{cite news | url=https://www.theguardian.com/science/2013/jan/20/alfred-russel-wallace-forgotten-man-evolution | title=Alfred Russel Wallace, the forgotten man of evolution, gets his moment | newspaper=The Guardian | date=20 January 2013 | access-date=6 October 2013 | author=McKie, Robin}}</ref><ref name=NHM>{{cite web | url=http://www.nhm.ac.uk/nature-online/science-of-natural-history/wallace/index.html | title=Wallace100 – celebrating Alfred Russel Wallace's life and legacy | publisher=Natural History Museum | year=2013 | access-date=5 October 2013}}</ref> On 24 January, his portrait was unveiled in the Main Hall of the museum by Bill Bailey, a fervent admirer.<ref>[https://www.theguardian.com/science/2013/jan/20/alfred-russel-wallace-forgotten-man-evolution "Alfred Russel Wallace, the forgotten man of evolution, gets his moment"] ''{{wipe|The Guardian}}''. Retrieved 3 May 2013.</ref> Bailey further championed Wallace in his 2013 BBC Two series "Bill Bailey's Jungle Hero".<ref>[https://www.bbc.co.uk/blogs/tv/posts/Bill-Baileys-Jungle-Hero-An-audience-with-the-Sultan Bill Bailey's Jungle Hero: An audience with the sultan"] ''BBC TV Blog''. Retrieved 3 May 2013.</ref> On 7 November 2013, the 100th anniversary of Wallace's death, Sir [[Biography:David Attenborough|David Attenborough]] unveiled a statue of Wallace at the museum.<ref>[http://www.nhm.ac.uk/about-us/news/2013/november/sir-david-attenborough-unveils-wallace-statue125452.html Natural History Museum: David Attenborough unveils Wallace Statue] {{webarchive|url=https://web.archive.org/web/20131113140230/http://www.nhm.ac.uk/about-us/news/2013/november/sir-david-attenborough-unveils-wallace-statue125452.html |date=13 November 2013 }}. Retrieved 13 November 2013.</ref> The statue, sculpted by Anthony Smith, was donated by the A. R. Wallace Memorial Fund.<ref>[https://wallacefund.myspecies.info/bronze-statue-wallace "Bronze statue of Wallace"]. Retrieved 10 January 2014.</ref> It depicts Wallace as a young man, collecting in the jungle. November 2013 marked the debut of ''The Animated Life of A. R. Wallace'', a paper-puppet animation film dedicated to Wallace's centennial.<ref name=NYT>{{cite news|last1=Lichtman|first1=Flora|title=The Animated Life of A.R. Wallace|url=https://www.nytimes.com/2013/11/05/opinion/the-animated-life-of-ar-wallace.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2013/11/05/opinion/the-animated-life-of-ar-wallace.html |archive-date=1 January 2022 |url-access=limited|newspaper=The New York Times|date=5 November 2013|access-date=27 June 2014}}{{cbignore}}</ref> In addition, Bailey unveiled a bust of Wallace, sculpted by Felicity Crawley, in Twyn Square in Usk, Monmouthshire in November 2021.<ref>{{cite news |url=https://www.abergavennychronicle.com/news/comedian-to-unveil-bronze-bust-of-famous-son-wallace-75960 |first=Nick |last=Hartland |title=Comedian to unveil bust of famous son Wallace |publisher=Abergavenny Chronicle |date=6 November 2021 |access-date=11 August 2022 |archive-url=https://web.archive.org/web/20220811063826/https://www.abergavennychronicle.com/news/comedian-to-unveil-bronze-bust-of-famous-son-wallace-75960 |archive-date=11 August 2022 |url-status=live}}</ref>

=== Memorials ===

Mount Wallace in California's Sierra Nevada mountain range was named in his honour in 1895.<ref>Peter Browning, ''Place Names of the Sierra Nevada From Abbot to Zumwalt'', 1986, Wilderness Press, {{ISBN|9780899970479}}.</ref> In 1928, a [[Social:House system|house]] at Richard Hale School (then called Hertford Grammar School, where he had been a pupil) was named after Wallace.<ref name="fun facts">{{cite web|title=Just for Fun |url=http://people.wku.edu/charles.smith/wallace/just.htm |publisher=The Alfred Russel Wallace Page |access-date=30 November 2015}}</ref><ref name="other things"/> Lecture theatres at Swansea and Cardiff universities are named after him,<ref name="other things">{{cite web |title=Other things named after Wallace |url=http://wallacefund.info/other-things-named-after-wallace |publisher=The Alfred Russel Wallace Website |access-date=30 November 2015}}</ref> as are [[Astronomy:Impact crater|impact crater]]s on Mars and the [[Astronomy:Moon|Moon]].<ref name="fun facts"/> In 1986, the Royal Entomological Society mounted a year-long expedition to the Dumoga-Bone National Park in North Sulawesi named Project Wallace.<ref name="other things"/> A group of Indonesian islands is known as the [[Biology:Wallacea|Wallacea]] biogeographical region in his honour, and Operation Wallacea, named after the region, awards "Alfred Russel Wallace Grants" to undergraduate ecology students.<ref>{{cite web |title=Alfred Russel Wallace Grants |url=http://opwall.com/about-us/alfred-russel-wallace-grants/ |publisher=Operation Wallacea |access-date=22 November 2015 |url-status=dead |archive-url=https://web.archive.org/web/20151123092245/http://opwall.com/about-us/alfred-russel-wallace-grants/ |archive-date=23 November 2015}}</ref> Several hundred species of plants and animals, both living and fossil, have been named after Wallace,<ref>{{cite web |last=Beccaloni |first=H. |date=October 2017 |title=Plants and animals named after Wallace |url=http://wallacefund.info/plants-and-animals-named-after-wallace | publisher=The Alfred Russel Wallace Website |access-date=26 October 2017 }}</ref> such as the gecko ''[[Biology:Cyrtodactylus wallacei|Cyrtodactylus wallacei]]'',<ref>Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. {{ISBN|978-1-4214-0135-5}}. ("Wallace", p. 279).</ref> and the freshwater stingray ''[[Biology:Potamotrygon|Potamotrygon]] wallacei''.<ref>{{cite journal |author1=Carvalho, M.R.d. |author2=Rosa, R.S.|author3=Araújo, M.L.G. |year=2016 |title=A new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the Rio Negro, Amazonas, Brazil: the smallest species of Potamotrygon |journal=Zootaxa |volume=4107 |issue=4 |pages=566–586 |doi=10.11646/zootaxa.4107.4.5 |pmid=27394840 }}</ref>

== Writings ==
[[File:Alfred Russel Wallace, attributed to John William Beaufort (1864-1943).jpg|thumb|upright|Portrait of Wallace, attributed to John William Beaufort (1864–1943)|alt=portrait painting of Wallace]]

Wallace was a prolific author. In 2002, a historian of science published a quantitative analysis of Wallace's publications. He found that Wallace had published 22 full-length books and at least 747 shorter pieces, 508 of which were scientific papers (191 of them published in ''Nature''). He further broke down the 747 short pieces by their primary subjects: 29% were on biogeography and natural history, 27% were on evolutionary theory, 25% were social commentary, 12% were on anthropology, and 7% were on spiritualism and phrenology.{{sfn|Shermer|2002|pp=15–17}} An online bibliography of Wallace's writings has more than 750 entries.<ref name="Bibliography"/> 

<!--standardised notice-->
{{botanist|Wallace|inline=yes}}

== See also ==

* [[Biology:History of biology|History of biology]]
* List of independent discoveries

== Notes ==

{{notelist}}

== References ==

{{reflist|24em}}

===Sources===

{{refbegin}}
* {{cite book |last1=Bowler |first1=Peter J. |last2=Morus |first2=Iwan Rhys |title=Making Modern Science |publisher=The University of Chicago Press |year=2005 |isbn=978-0-226-06861-9|url=https://archive.org/details/makingmodernscie0000bowl_b4z3|url-access=registration}}
* {{cite book |last=Bowler |first=Peter J. |title=Evolution: The History of an Idea |year=1989 |publisher=University of California Press |isbn=0520063864 |url=https://archive.org/details/evolutionhistory0000bowl|url-access=registration}}
* {{cite book |last=Bowler |first=Peter J. |title=Darwin Deleted |publisher=The University of Chicago Press |year=2013 |isbn=978-0-226-00984-1}}
* {{cite book |last=Browne |first=Janet |title=Charles Darwin: Voyaging: Volume I of a Biography |publisher=Princeton University Press |year=1995 |isbn=978-1-84413-314-7|url=https://archive.org/details/charlesdarwinbio0001brow|url-access=registration}}
* {{cite book |last=Browne |first=Janet |title=Charles Darwin: The Power of Place: Volume II of a Biography |publisher=Princeton University Press |year=2002 |isbn=978-0-691-11439-2|url=https://archive.org/details/charlesdarwinbio0002brow|url-access=registration}}
* {{cite journal |last=Darwin |first=Charles |last2=Wallace |first2=Alfred Russel |year=1858 |title=On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection |journal=Zoological Journal of the Linnean Society |volume=3 |issue=9 |pages=46–62 |doi=10.1111/j.1096-3642.1858.tb02500.x |url=http://darwin-online.org.uk/content/frameset?itemID=F350&viewtype=text&pageseq=1 |access-date=20 September 2022 |doi-access=free }}
* {{cite book |last=Darwin |first=Charles |editor-last=Darwin |editor-first=Francis |title=The life and letters of Charles Darwin, including an autobiographical chapter |series=Vol. 2 |year=2009 |orig-year=1887 |publisher=John Murray }}
* {{cite book |last1=Desmond |first1=Adrian |last2=Moore |first2=James |author-link2=James Moore (biographer) |title=Darwin |publisher=Michael Joseph, Penguin Group |year=1991 |isbn=978-0-7181-3430-3 |url=https://archive.org/details/darwin0000desm|url-access=registration}}
* {{cite book |last=Flannery |first=Tim |title=Here on earth: a natural history of the planet |publisher=Atlantic Monthly Press |year=2010 |isbn=978-0-8021-1976-6|url=https://archive.org/details/hereonearthnatur0000flan|url-access=registration}}
* {{cite book |last=Larson |first=Edward J. |title=Evolution: The Remarkable History of Scientific Theory |publisher=Modern Library |year=2004 |isbn=978-0-679-64288-6 |url=https://archive.org/details/evolutionremarka00lars|url-access=registration}}
* {{cite book |last=Marchant |first=James |title=Alfred Russel Wallace: letters and reminiscences |url=http://darwin-online.org.uk/content/frameset?itemID=F1593&viewtype=image&pageseq=1 |year=1916 |publisher=Harper & Brothers |location=New York}}<!--The UK edition published in the same year by Cassel is in 2 vols. Available on Int Arch-->
* {{cite book |last=McGowan |first=Christopher |title=The Dragon Seekers |publisher=Perseus Pub |location=Cambridge |year=2001 |isbn=978-0-7382-0282-2 |url=https://archive.org/details/dragonseekershow00mcgo_0 |url-access=registration}}
* {{cite book |last=Raby |first=Peter |title=Alfred Russel Wallace: A Life |publisher=Princeton University Press |year=2002 |isbn=978-0-691-10240-5}}
* {{cite book |last=Shermer |first=Michael |title=In Darwin's Shadow: The Life and Science of Alfred Russel Wallace |publisher=Oxford University Press |year=2002 |isbn=978-0-19-514830-5 |url=https://books.google.com/books?id=gSSkPqmbeXIC}}
* {{cite book |last=Slotten |first=Ross A. |title=The Heretic in Darwin's Court: the life of Alfred Russel Wallace |publisher=Columbia University Press |location=New York |year=2004 |isbn=978-0-231-13010-3 |url=https://archive.org/details/hereticindarwins00ross |url-access=registration }}
* {{cite book |last=van Wyhe |first=John |title=Dispelling the Darkness: Voyage in the Malay Archipelago and the Discovery of Evolution by Wallace and Darwin |url=https://books.google.com/books?id=fpi6CgAAQBAJ&pg=PA111 |year=2013 |publisher=World Scientific |isbn=978-981-4458-79-5 }}
* {{cite book |last=Wallace |first=Alfred Russel |year=1875 |url=https://archive.org/stream/onmiraclesmodern00wall#page/172/mode/2up |title=On Miracles and Modern Spiritualism |publisher=James Burns |oclc=22744309 }}
* {{cite book |last=Wallace |first=Alfred Russel |year=1876 |title=The Geographical Distribution of Animals |publisher=Macmillan |url=https://archive.org/details/bub_gb_8lAPAAAAYAAJ}}
* {{cite book |last=Wallace |first=Alfred Russel |title=Island Life |url=https://archive.org/details/islandlifeorphe02wallgoog |year=1881 |publisher=Harper and brothers }}
* {{cite web |last=Wallace |first=Alfred Russel |year=1889 |publisher=The Alfred Russel Wallace Page |access-date=4 April 2007 |url=http://www.wku.edu/~smithch/wallace/S724CH15.htm |title=''Darwinism'', Chapter 15 |archive-url=https://web.archive.org/web/20070313182223/http://www.wku.edu/~smithch/wallace/S724CH15.htm |archive-date=13 March 2007 |url-status=live}}
* {{cite book |last=Wallace |first=Alfred Russel |year=1905a |title=My Life: A Record of Events and Opinions |volume=I |publisher=Chapman and Hall |url=https://archive.org/details/b31360580_0001}} [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.1&pageseq=1 Vol. 1]
* {{cite book |last=Wallace |first=Alfred Russel |year=1905b |title=My Life: A Record of Events and Opinions |volume=II |publisher=Chapman and Hall |url=https://archive.org/details/b31360580_0002}}. [http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=A237.2&pageseq=1 Vol. 2]
* {{cite book |last=Wallace |first=Alfred Russel |year=1911 |title=The World of Life |publisher=Moffat, Yard |url=https://archive.org/details/worldlifeamanif00wallgoog}}
* {{cite book |last=Wilson |first=John |title=The Forgotten Naturalist: In search of Alfred Russel Wallace |publisher=Arcadia/Australian Scholarly Publishing |year=2000 |isbn=978-1-875606-72-6 }}
{{refend}}

== Further reading ==

There is an extensive literature on Wallace. Recent books on him<!-- other than those used as Sources, see below--> include: 

{{refbegin}}
* {{cite book |last=Benton |first=Ted |title=Alfred Russel Wallace: Explorer, Evolutionist, Public Intellectual: A Thinker for Our Own Times? |year=2013 |isbn=978-0-9574530-2-9 |publisher=Siri Scientific Press |location=Manchester |ref=none }}
* {{cite book |last=Berry |first=Andrew |title=Infinite Tropics: An Alfred Russel Wallace Anthology |year=2003 |isbn=978-1-85984-478-6 |publisher=Verso |location=London |ref=none }}
* {{cite book |last=Costa |first=James T. |year=2014 |title=Wallace, Darwin, and the Origin of Species |location=Cambridge, Massachusetts |publisher=Harvard University Press |isbn= 978-0-674-72969-8 |ref=none }}
* {{cite book | last=Costa |first=James T., annotated by |title=On the Organic Law of Change, A Facsimile Edition and Annotated Transcription of Alfred Russel Wallace's Species Notebook of 1855–1859 |year=2013 |publisher=Harvard University Press |isbn=978-0-674-72488-4 |ref=none }}
* {{cite book |last=Crawforth |first=Anthony |title=The Butterfly Hunter: The Life of Henry Walter Bates |year=2009 |publisher=The University of Buckingham Press |isbn=978-0-9560716-1-3 |ref=none }}
* {{cite book |last=Fichman |first=Martin |title=An Elusive Victorian: The Evolution of Alfred Russel Wallace |year=2004 |isbn=978-0-226-24613-0 |publisher=University of Chicago Press |location=Chicago |url=https://archive.org/details/elusivevictorian00fich |ref=none }}
* {{cite book |editor-last=Marchant |editor-first=James |title=Alfred Russel Wallace: Letters and Reminiscences, ''Vol. 1'' ''(Parts I and II)'' |year=1916 |format=Project Gutenberg |url=http://www.gutenberg.org/ebooks/15997 |ref=none }} [http://www.gutenberg.org/ebooks/15998 Vol. 2 (Parts III – VII)] (Project Gutenberg). London: Cassell and Company. Published in a single volume by Harper & Brothers Publishers, New York and London, June 1916.
* {{cite book |last=Severin |first=Tim |title=The Spice Islands Voyage: The Quest for Alfred Wallace, the Man Who Shared Darwin's Discovery of Evolution |year=1997 |isbn=978-0-7867-0518-4 |publisher=Carroll & Graf Publishers |location=New York |url=https://archive.org/details/spiceislandsvoya00seve |ref=none }}
* {{cite book |editor-last1=Smith |editor-first1=Charles H. |editor1-link=Charles H. Smith (historian) |editor2-last=Costa |editor2-first=James T. |editor3-last=Collard |editor3-first=David |year=2019 |title=An Alfred Russel Wallace Companion |place=Chicago |publisher=The University of Chicago Press |ref=none }}
* {{cite book |last=Sochaczewski |first=Paul Spencer |title=An Inordinate Fondness for Beetles: Campfire Conversations with Alfred Russel Wallace on People and Nature Based on Common Travel in the Malay Archipelago |year=2012 |isbn=978-981-4385-20-6 |publisher=Editions Didier Millet |location=Singapore |ref=none }}
* {{cite book | last1=van Wyhe |first1=John |last2=Rookmaaker |first2=Kees |title=Alfred Russel Wallace: Letters from The Malay Archipelago |year=2013 |publisher=Oxford University Press |place=Oxford |isbn=978-0-19-968399-4 |ref=none }}
{{refend}}

== External links ==

* [https://wallacefund.myspecies.info/ The Alfred Russel Wallace Website by George Beccaloni]
* [http://people.wku.edu/charles.smith/index1.htm Alfred Russel Wallace at [[Organization:Western Kentucky University|Western Kentucky University]] ]
* [https://wallaceletters.myspecies.info/ The A. R. Wallace Correspondence Project Homepage]
* [https://www.flickr.com/photos/wallace_memorial_fund/albums The Wallace Memorial Fund's gallery of Wallace-related images]
* [https://web.archive.org/web/20100124191414/http://www.100welshheroes.com/en/biography/alfredrussellwallace Wallace at 100 Welsh Heroes]
* [http://wallace-online.org/ Wallace Online. The first complete online edition of the writings of Alfred Russel Wallace]
* {{Gutenberg author|id=Wallace,+Alfred+Russel}}
* {{Internet Archive author |sname=Alfred Russel Wallace}}
* {{Librivox author |id=4452}}
* [https://www.bbc.co.uk/programmes/m000cldv Great Lives – Bill Bailey on his hero Alfred Russel Wallace]

{{Copley Medallists 1901-1950}}
{{Zoology}}


{{DEFAULTSORT:Wallace, Alfred Russel}}
[[Category:Evolutionary biologists]]
[[Category:Geometers]]

{{Sourceattribution|Alfred Russel Wallace|1}}