Simpson, George Gaylord (1902–1984)

US palaeontologist who studied the evolution of mammals. He applied population genetics to the subject and to analyse the migrations of animals between continents.

Simpson was born in Chicago; he attended the University of Colorado and Yale. From 1927 he worked at the American Museum of Natural History, becoming curator 1942. He was professor at Columbia 1945–59, at Harvard 1959–70, and at Arizona from 1967.

Simpson's work in the 1930s concerned early mammals of the Mesozoic era and the Palaeocene and Eocene epochs, which entailed many extensive field trips throughout the Americas and to Asia to study fossil remains. In the 1940s he began applying genetics to mammalian evolution and classification.

He wrote several textbooks, including The Meaning of Evolution 1949, The Major Features of Evolution 1953, and The Principles of Animal Taxonomy 1961, which were influential in establishing the neo-Darwinian theory of evolution.