American biologist recognized as the world's leading authority on ants (ant). He was also the foremost proponent of sociobiology, the study of the genetic basis of the social behaviour of all animals, including humans.

Wilson received his early training at the University of Alabama (B.S., 1949; M.S., 1950). After receiving his doctorate in biology at Harvard University in 1955, he was a member of Harvard's biology and zoology faculties from 1956 to 1976. At Harvard he was later Frank B. Baird Professor of Science (1976–94), Mellon Professor of the Sciences (1990–93), and Pellegrino University Professor (1994–97). He was professor emeritus from 1997. In addition, Wilson served as curator in entomology at Harvard's Museum of Comparative Zoology (1973–97).

In 1955 Wilson completed an exhaustive taxonomic analysis of the ant genus Lasius. In collaboration with W.L. Brown, he developed the concept of “character displacement,” a process in which populations of two closely related species, after first coming into contact with each other, undergo rapid evolutionary (evolution) differentiation (biological development) in order to minimize the chances of both competition and hybridization between them.

After his appointment to Harvard in 1956, Wilson made a series of important discoveries, including the determination that ants communicate primarily through the transmission of chemical substances known as pheromones (pheromone). In the course of revising the classification of ants native to the South Pacific, he formulated the concept of the “ taxon cycle,” in which speciation and species dispersal are linked to the varying habitats that organisms encounter as their populations expand. In 1971 he published The Insect Societies, his definitive work on ants and other social insects. The book provided a comprehensive picture of the ecology, population dynamics, and social behaviour of thousands of species.

In Wilson's second major work, Sociobiology: The New Synthesis (1975), a treatment of the biological basis of social behaviour, he proposed that the essentially biological principles on which animal societies are based also apply to humans. This thesis provoked condemnation from prominent researchers and scholars in a broad range of disciplines, who regarded it as an attempt to justify harmful or destructive behaviour and unjust social relations in human societies. In fact, however, Wilson maintained that as little as 10 percent of human behaviour is genetically induced, the rest being attributable to environment.

One of Wilson's most notable theories was that even a characteristic such as altruism may have evolved through natural selection. Traditionally, natural selection was thought to foster only those physical and behavioral traits that increase an individual's chances of reproducing. Thus, altruistic behaviour—as when an organism sacrifices itself in order to save other members of its immediate family—would seem incompatible with this process. In Sociobiology Wilson argued that the sacrifice involved in much altruistic behaviour results in saving closely related individuals—i.e., individuals who share many of the sacrificed organism's genes (gene). Therefore, the preservation of the gene, rather than the preservation of the individual, was viewed as the focus of evolutionary strategy. In later years, however, Wilson was inclined to think that highly social organisms are integrated to such an extent that they are better treated as one overall unit—a superorganism—rather than as individuals in their own right. This view was suggested by Charles Darwin (Darwin, Charles) himself in On the Origin of Species (1859). Wilson expounded on it in Success, Dominance, and the Superorganism: The Case of the Social Insects (1997).

In On Human Nature (1978), for which he was awarded a Pulitzer Prize in 1979, Wilson discussed the application of sociobiology to human aggression, sexuality (sex), and ethics. His book The Ants (1990) was a monumental summary of contemporary knowledge of those insects. In The Diversity of Life (1992), Wilson sought to explain how the world's living species became diverse and examined the massive species extinctions (extinction) caused by human activities in the 20th century.

In his later career Wilson turned increasingly to religious and philosophical topics. In Consilience: The Unity of Knowledge (1998), he strove to demonstrate the interrelatedness and evolutionary origins of all human thought. In Creation: An Appeal to Save Life on Earth (2006), he developed further the evolutionarily informed humanism he had earlier explored in On Human Nature. In contrast to many other biologists, notably Stephen Jay Gould (Gould, Stephen Jay), Wilson believed that evolution is essentially progressive, leading from the simple to the complex and from the worse-adapted to the better. From this he inferred an ultimate moral imperative for humans: to cherish and promote the well-being of their species.

In 1990 Wilson and American biologist Paul Ehrlich (Ehrlich, Paul R) shared the Crafoord Prize, awarded by the Royal Swedish Academy of Sciences to support areas of science not covered by the Nobel Prizes. His autobiography, Naturalist, appeared in 1994.