SJG Archive

The Unofficial Stephen Jay Gould Archive

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Biographical Sketch

During the 1930s, George Gaylord Simpson of the American Museum of Natural History exerted a major influence on bringing paleontology into the modern Synthetic Theory of evolution, which had already become the theoretical umbrella for genetics, zoology, taxonomy and studies of plant and animal populations. While most paleontologists had become accustomed to think of a series of types "leading to" the modern forms, Simpson's attempt to approach the fossil record as a sampling of ancient breeding populations led to a revitalization of the field.

George G. Simpson
George Gaylord Simpson  

Simpson had joined the American Museum of Natural History as assistant curator of vertebrate paleontology in 1927, at the invitation of director Henry Fairfield Osborn, who had a knack for picking future "stars" in natural history. Simpson's productive field trips to the American West and to Patagonia added much new information on the evolution and distribution of extinct mammals of the New World. Traditionally, fossil-hunters had sought magnificent specimens for their museums and exhibited them as a series of individuals, like O. C. Marsh's famous linear "progression" of individual horse skeletons. Simpson made the evolution of the horse one of his specialties; his detailed, quantitative studies, published in his classic book Horses (1951), exploded Marsh's "single-line" evolution of the horse from a fox-sized hoofless ancestor.

Instead, Simpson showed the complex and diverse branching of the horse's ancient relatives, not only through time, but over geographica area, as early populations pushed into various habitats, adapting first to forests, then to open grasslands. Horses represented a complex, branching bush of diverging species—nothing like a line leading straight from Eohippus to old Dobbin.

A pioneer in tackling the problem of rates of evolution, Simpson was impressed with the pattern of long periods of stability in species, interspersed with relatively rapid change. Creationists had seen these "discontinuities" as evidence that no evolution had occurred, while Darwin considered them gaps in an imperfect fossil record. Employing Sewall Wright's idea of genetic drift, Simpson argued that important changes might occur fairly rapidly in very small populations, leaving little fossil evidence before they spread and stabilized in large numbers. In his book Tempo and Mode in Evolution (1944), he introduced the term "quantum evolution" for the phenomena, a precursor of the theory of punctuated equilibrium.

He was also an engaging and popular writer: His journals of his travels and explorations attracted a wide readership (Attending Marvels: A Patagonian Journal, 1934). Simpson's lively and often definitive discussions of evolutionary theory and its history can be found in The Major Features of Evolution (1965), Evolution and Geography (1953) and his delightful Book of Darwin (1982), a personal guide to the life and works of the patriarch of evolutionary biology.

[ Richard Milner, The Encyclopedia of Evolution, NY: Facts on File, 1990, pp. 405-406. ]

Stephen Jay Gould on G. G. Simpson


As my first two scientific commitments, I fell in love with paleontology when I met Tyrannosaurus in the Museum of Natural History at age five, and with evolution at age 11, when I read G. G. Simpson's The Meaning of Evolution, with great excitement but minimal comprehension, after my parents, as members of a book club for folks with intellectual interests but little economic opportunity or formal credentials, forgot to send back the "we don't want anything this month" card, and received the book they would never have ordered (but that I begged them to keep because I saw the little stick figures of dinosaurs on the dust jacket). Thus, from day one, my developing professional interests united paleontology and evolution. For some reason still unclear to me, I always found the theory of how evolution works more fascinating than the realized pageant of its paleontological results, and my major interest therefore always focused upon principles of macroevolution.


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