Contributions to the Theory of Natural Selection A Series of Essays

Alfred Russel Wallace OM FRS was an English naturalist, explorer, geographer, anthropologist, biologist, and illustrator who lived from 8 January 1823 to 7 November 1913. He independently developed the theory of evolution by natural selection, and his work on the subject was published in 1858, with excerpts from Charles Darwin's earlier papers on the subject. It inspired Darwin to abandon the "big species book" he was working on and rapidly compose an abstract, which was published in 1859 as On the Origin of Species. Wallace conducted significant field research, beginning in the Amazon River basin. He then conducted fieldwork in the Malay Archipelago, where he discovered the Wallace Line, which divides the Indonesian archipelago into two distinct parts: a western portion with animals primarily of Asian origin, and an eastern portion with animals primarily of Australasia. He was regarded as the preeminent authority on the geographical distribution of animal species in the nineteenth century, and is frequently referred to as the "father of biogeography," or more particularly zoogeography. Wallace was a notable evolutionary thinker of the nineteenth century, working on warning coloration in animals and reinforcement (also referred to as the Wallace effect), a method by which natural selection could contribute to speciation by stimulating the establishment of barriers against hybridization.