George Gaylord Simpson

**George Gaylord Simpson** (16 June 1902 – 6 October 1984) was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis.

He was an expert on extinct mammals and their migrations, especially the Great American Interchange between the Americas. Simpson  opposed Alfred Wegener's theory of continental drift, so his work on animal migration lacked this idea.

Simpson dispelled the myth that the evolution of the horse was a linear process culminating in the modern _Equus caballus_. He coined the word _hypodigm_ in 1940, and published extensively on the taxonomy of fossil and living mammals.

## Biography

Born in Chicago, Illinois, Simpson was raised mostly in Denver, Colorado. He got his degrees from Yale University in 1923 and 1926. His dissertation, _American Mesozoic Mammalia_ (1929), was the first step in his lifelong interest in the evolution of mammals. After a post-doctoral year at the British Natural History Museum, Simpson returned in 1927 to take up a post in the American Museum of Natural History.

In 1942, Simpson enlisted in the U.S. Army. He served as a Captain, then Major, in Army intelligence, Simpson served with American forces in North Africa and western Europe until 1944. Then he resigned, suffering from a severe bout of hepatitis. He returned home, with two Bronze Stars. He was promoted to Curator (head) of the Department of Geology and Paleontology at the American Museum of Natural History. He also held a post as Professor of Zoology at Columbia University (19451959). He took up his work on early mammals, and worked on the Palaeocene and Eocene faunas of the San Juan Basin, New Mexico.

He was Curator of the Museum of Comparative Zoology at Harvard University from 1959 to 1970, and a Professor of Geosciences at the University of Arizona until his retirement in 1982.

## Major works and awards

In the 1940s Simpson produced three major works. _Tempo and mode in evolution_ (1944), _Principles of classification and a classification of mammals_ (1945) and _The meaning of evolution_ (1949). Simpson provided a popular account of modern evolutionary theory with emphasis on evidence from the fossil record.

Simpson was awarded the Linnean Society's Darwin-Wallace Medal in 1958. He also received the Royal Society's Darwin Medal "In recognition of his distinguished contributions to general evolutionary theory, based on a profound study of palaeontology, particularly of vertebrates" in 1962. He was awarded the U.S. National Medal of Science in 1965.

## Quotes

These quotations from Simpson give a good idea of the man:
- "Man is the result of a purposeless and natural process that did not have him in mind".
- "I don't think that evolution is supremely important because it is my specialty; it is my specialty because I think it is supremely important".

## Books

- _Attending marvels_ (1931)
- _Tempo and mode in evolution_ (1944)
- _The meaning of evolution_ (1949)
- _Horses_ (1951)
- _Evolution and geography_ (1953)
- _The major features of evolution_ (1953)
- _Life: an introduction to biology_ (1957)
- _Principles of animal taxonomy_ (1961)
- _This view of life_ (1964)
- _The geography of evolution_ (1965)
- _Penguins_ (1976)
- _Concession to the improbable_ (1978) (an autobiography)
- _Splendid isolation_ (1980)
- _The Dechronization of Sam Magruder_ (posthumously published novella, 1996)

## Other websites

- George Gaylord Simpson — full and comprehensive biography by L. F. Laporte
- George Gaylord Simpson  — biographical sketch from The Stephen Jay Gould Archive
- George Gaylord Simpson — a short biography from the PBS _Evolution_ website
- George Gaylord Simpson Papers, American Philosophical Society.