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.
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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
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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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