hen
five-year-old Stephen Jay Gould first marveled at the towering
Tyrannosaurus
skeleton in the American Museum of Natural History, he decided to spend his life
studying fossils. Although few children in Queens, New York, shared his early
fascination for evolution, he never considered any other career but paleontology.
Now professor at Harvard University and curator of its Museum of
Comparative Zoology, Gould attended
Antioch
College, then returned to Manhattan, for graduate work in paleontology at Columbia
University. For his doctoral thesis he investigated variation and evolution in an
obscure Burmudian land snail, anchoring his later theorizing in intense scrutiny of a
single group of organisms, as Darwin had done with
Barnacles.
At one point, he hoped to find correlation between variation and
different ecologies within the creature's range, but the snails' sizes, colors and
shell shapes seemed to vary quite independently of local environment. Impressed with
the importance of nonselectionist factors in evolution, he also became interested in
structural constraints: How slight changes in one feature must alter several others
within definite limits—what Darwin had called "correlation of parts."
Gould also became interested in distinguishing incidental features
from adaptive ones. He coauthored (with Richard Lewontin) an influential paper
inspired by the spandrels of certain medieval cathedrals: Geometric
architectural features decorated with impressive religious paintings. While art
historians had analyzed their distinctive aesthetic, most had forgotten the spandrel's
humble origin as an unavoidable engineering consequences of stress distribution—a
structural byproduct of constructing that kind of dome. As a biological example, Gould
points out that the human chin, often cited as "advanced" in comparisons with "lower"
primates, holds no special correlation with higher intelligence. It is, like the
spandrels, an incidental result of stress and growth factors in the human jawbone.
Although Gould has become closely identified with the influential
idea of punctuated equilibrium, it actually originated with paleontologist Niles
Eldredge and was developed by them jointly. Eldredge's detailed studies of trilobites
brought home to him a pattern that had impressed Thomas Henry Huxley: The fossil
record seems to show "bursts" of speciation, then long periods of stability. Darwin's
reply was that the fossil record was then too sketchy and incompletely known to
provide evidence of pattered rates. But vast accumulations of paleontological evidence
over the last century do not support Darwin's case for a steady, gradual evolutionary
rate. Eldredge's trilobite series suggested, instead, relatively short episodes
of rapid evolution followed by long periods of stability, confirming Huxley's impression.
Gould enthusiastically agreed; it was time to acknowledge that such episodic patterns in
the rocks probably reflect the reality of life's history. By the 1980s, "Punctuationalism"
had become widely adopted and was proving to be a fruitful hypothesis for generating new
insights and research. Although one of Gould's lifelong heroes is Charles Darwin, whose
achievements he has celebrated in such books as Ever Since Darwin
(1977) and The Panda's Thumb (1980), he is irreverent toward the
orthodox Synthetic Theory of evolution that has prevailed in biology since the 1940s.
Dissatisfied with the limits of its explanatory power, he is open to exploring other
possible mechanisms and approaches to supplement traditional natural selection—to
the dismay of more conservative colleagues.
One of his approaches has been to emphasize the hierarchy of levels
on which evolution operates; biochemical, genetic, embryological, physiological,
individual, societal, species, lineages. Sorting or selection on any of these levels,
he believes, produces significant effects on the level above or below it—a
promising and largely unexplored area for future research. Yale paleontologist Elisabeth
Vrba and others agree with Gould about the importance of such hierarchical studies.
Among opponents of punctuationalism, a few (Richard Dawkins,
Verne Grant)
complain Gould has set up a "straw man" of Darwinian gradualism and that jumpy
or "quantum evolution" was
discussed years ago by Ernst
Mayr and George Gaylord Simpson. Examples
of Darwin's self-contradictory fudging are easy to find, but Gould maintains that change
"by slow, insensible degrees" remained central to Darwinian thought. And while
acknowledging his predecessors' insights, Gould argues that often it is a shift of
emphasis and focus rather than a radically new idea that leads to deeper scientific
understanding.
Gould's success as a popular author is another tempting target for
critics; he does not shrink from public controversies. He appeared before
Congressional committees on environmental issues, was a courtroom witness in the
Arkansas Scopes II trial regarding teaching of evolution in the public schools and is
prominent in speaking out against pseudo-scientific racism and biological determinism.
But even one of his most adamant detractors, Robert Wright, while recently attacking
one of his books in the pages of The New Republic, grudgingly
began his diatribe: "The acclaim for Stephen Jay Gould is just shy of being universal
. . . He is, after all, America's evolutionist laureate."
[ Richard Milner,
The
Encyclopedia of Evolution, NY: Facts on File, 1990, pp. 198-199. ]
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