Alfred Russel Wallace

Alfred Russel Wallace (b. 1823–d. 1913) was one of the most brilliant theoretical and field biologists of the 19th century. He was a meticulous field observer, a prolific generator of ideas on a broad spectrum of issues ranging from evolutionary biology to social and political concerns, and a theoretician whose work laid some of the main foundations for the scientific study of biogeography and evolution. Wallace undertook two tropical journeys that were to transform his life and the emerging science of evolutionary biology: a four-year exploration of the Amazon basin of South America (1848–1852) and an eight-year exploration of the Malay Archipelago (1854–1862), including the islands of Java, Borneo, Celebes, New Guinea, and Bali. Wallace later generalized his findings from Southeast Asia to elaborate a global paradigm for identifying the earth’s fundamental biogeographical regions in his magisterial Geographical Distribution of Animals (1876). It was, of course, Wallace’s elucidation of the mechanism of evolution—in his 1858 “On the Tendency of Varieties to Depart Indefinitely from the Original Type”—that constitutes his greatest scientific legacy from his Malay travels. A copy of Wallace’s essay, along with extracts from an unpublished manuscript on natural selection written by Darwin in 1844, were presented together at the historic meeting of the Linnean Society (London) on 1 July 1858. This meeting—a year prior to the publication of Darwin’s On the origin of species (1859)—ensured that both Wallace and Darwin received recognition and joint priority for their momentous discovery of natural selection. Wallace spent the remainder of his long life in elucidating the implications of evolutionary theory for biogeography, sexual selection, the phenomenon of organic mimicry taxonomy, physical geography and geology, and anthropology. Although he remained an ardent selectionist in his overall analysis of evolutionary processes, Wallace considered natural selection inadequate to account completely for the origin and development of certain human characteristics, notably, consciousness and the moral sense. He insisted that certain aspects of theism and of political and social ideologies, including socialism, spiritualism, and anti-vaccinationism, were not merely compatible with the evolutionary process but essential for comprehending the full significance of human evolution. The issues Wallace confronted continue to resonate in contemporary debates on the scope, mechanism, and, ultimately, significance of evolution in both scientific and cultural domains. In the past two decades there has been a resurgence of interest in Wallace, and this article provides a scholarly guide through the thicket of materials now emerging on his life and achievements.