Which scientist independently developed the theory of natural selection alongside Charles Darwin?

Alfred Russel Wallace independently developed the theory of natural selection alongside Charles Darwin.

Wallace reached his insight while studying the geographical distribution of animals in the Malay Archipelago. In 1858, he sent Darwin an essay outlining the mechanism, prompting Darwin to present their ideas jointly to the Linnean Society of London.

Darwin later published a much fuller treatment in On the Origin of Species, so popular accounts often give him primary credit. However, Wallace’s contribution was independent and scientifically important. He also became a major figure in biogeography and helped establish the Wallace Line, a boundary between Asian and Australasian animal distributions.

Wallace and Darwin agreed on natural selection, but Wallace later differed from Darwin on some issues, including human evolution. Wallace is sometimes confused with Thomas Henry Huxley, who strongly defended Darwin’s theory but did not independently formulate it.