Alfred Russel Wallace is most famous for his work on natural selection, independent of Charles Darwin, which may have impelled the latter to publish his own theory.
Whilst collecting specimens and researching in the Malay Archipelago in 1858, Wallace famously sent Darwin his paper On the Tendency of Varieties to Depart Indefinitely From the Original Type. The paper dealt with environmental impacts and the resulting divergence (or evolution) of species – a theory similar to, but not the same as, Darwin’s own ‘natural selection’. While Wallace’s theory developed around species adapting to environmental pressures to survive, Darwin’s theory looked at the pressure of competition between the same, or similar, species.
Darwin, who had promised to forward the paper to the renowned geologist Charles Lyell, believed the paper to be an outstanding abstract and even suggested to Lyell that he should send the paper to journals for publication on Wallace’s behalf. On 1 July 1858, a joint paper outlining each man’s theory entitled On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection (Wallace and Darwin respectively) was read out at the Linnean Society.
Father of Biogeography
A leading figure in the study of biogeography, Wallace is now known as the ‘father’ of the subject. He looked into different factors that might have an impact on the global distribution of species, for example land bridges and glaciation.
The Wallace Line, an invisible ‘line’ running through the Indonesia, is named after him and shows a clear divide in species belonging to the Asian and Australian continental shelves. Wallace travelled to, and studied, the Amazon basin, as well as the Malay Archipelago and Indonesia, as recounted in his book The Malay Archipelago (1869). A plate from this title shows a python being unceremoniously extracted from Wallace’s hut; the Linnean Society holds the skin from this snake in its collections. The Society also holds Wallace’s journals and many annotated books from his library.