US palaeontologist, whose work did much to shape the postwar development of palaeontology and its impact on evolutionary theory.
A native of Chicago, Simpson obtained his first degree in geology from Yale University and stayed there to obtain his doctorate in 1926, with a thesis on fossil mammals of the Mesozoic era. The following year he joined the American Museum of Natural History, New York, later becoming curator of the palaeontology department (1944–59). Here he published many papers, mostly concerning mammalian palaeontology, especially the primitive mammals of the Cretaceous and early Tertiary periods. He wrote the standard text American Mesozoic Mammalia (1929). During World War II he served with the US army in North Africa. After the war he was appointed professor of vertebrate palaeontology at Columbia University (1945–59), during which time he contributed to the debate on the nature of evolution, particularly in his books Tempo and Mode in Evolution (1944) and The Major Features of Evolution (1953). He also had influential views on the philosophical implications of evolutionary theory, published in The Meaning of Evolution (1949). He led several fossil excavations, including that of a major collection of ancestral horses, known as Eohippus, in Colorado. Simpson showed that horse evolution had undergone not a steady continuous development but considerable fluctuation in form in the face of changing environmental conditions.
In 1959 Simpson was appointed Alexander Agassiz Professor of Vertebrate Palaeontology at Harvard University, a post he held until 1970. He was also professor of geosciences at the University of Arizona (1967–82).
Subjects: Biological Sciences.