Sherrie L. Lyons, "Thomas Huxley: Fossils,
Persistence, and the Argument from Design," Journal of
the History of Biology 26 (1993): pp. 545-569.
Sherrie L. Lyons, "The Origins of T.H. Huxley's Saltationism: History in Darwin's Shadow," Journal of the History of Biology 28 (1995): pp. 463-494.
Since completing her doctorate on T.H. Huxley with historian Robert Richards at the University of Chicago, scholar Sherrie Lyons has been mapping out in fine detail the geography of Huxley's deep uncertainty about many of the tenets of Darwinism. As an anatomist interested in what he called the "architectural and engineering part of the business" of natural history, Huxley perceived the animal world as being divided into fundamental types, and thus, Lyons writes, "Huxley found that his own work confirmed the lack of transitional forms between major groups" (1995, 471). Yet Huxley was also a materialist who wished to explain the origins of organisms by naturalistic descent. "If he were to accept a theory of transmutation," Lyons observes, "he had somehow to reconcile the two ideas: interrelatedness vs. the absence of transitional forms." Huxley found his answer in the possiblity of "saltational" evolution. "Saltation allowed Huxley to explain the gaps in the fossil record, accept evolution, and, most importantly, maintain a belief in the concept of type" (1995, 492). Huxley was unpersuaded by Darwin's arguments explaining away the missing fossils. In a wry metaphor cited by Lyons, Huxley compared the evidence a scientific theory must provide to the title-deeds for an estate:
If a landed proprietor is asked to produce the title-deeds of his estate, and is obliged to reply that some of them were destroyed in a fire a century ago, and that some were carried off by a dishonest attorney; and that the rest are in a safe somewhere, but that he really cannot lay his hands upon them; he cannot I think, feel pleasantly secure, though all his allegations may be correct and his ownership indisputable.
Huxley later moderated his saltationist views as fossil discoveries appeared to confirm Darwin's gradualistic arguments, although he never warmed to natural selection. But saltation, Lyons argues, provided him with the means to accept evolution in the face of missing evidence. Saltation was, for Huxley, a deduction from naturalism--"a logical development," he said, "of Uniformitarianism" and provided, at least for a time, the only alternative to creation. "The hypothesis of evolution," Huxley said in an American lecture, "supposes that in all this vast progression there would be no breach of continuity, no point at which we could say 'This is a natural process,' and 'This is not a natural process.'" Huxley had come to see this as a necessary deduction from his definition of science: naturalism.
Robert E. Simmons and Lue Scheepers, "Winning by a Neck: Sexual Selection in the Evolution of Giraffe," The American Naturalist 148 (1996): pp. 771-786.
Recently, in one of his periodic bouts of debunking, Stephen Jay Gould examined the standard textbook story of the evolution of the giraffe's long neck ("The Tallest Tale," Natural History, May 1996, pp. 18-27). Despite its status as a chestnut of evolutionary lore, Gould argues, the standard story--the giraffe evolved its long neck in competition to reach scarce foliage high in trees--is supported by no evidence. And "when we turn to giraffes themselves," he continued, "we encounter the final irony of this long story. Giraffes provide no established evidence whatsoever for the mode of evolution of their undeniably useful necks" (26). Any of several current functions of the neck might explain its origin, he concludes, although the bottom line must be that we simply do not know. "In short, we have no basis for any firm assertion about the most famous inquiry among Darwinian just-so stories: how did the giraffe get its long neck?" (27).
In their article, "Winning by a Neck," zoologists Robert Simmons (Uppsala University) and Lue Scheepers (Ministry of Environment, Namibia) agree with Gould that the standard account "may be no more than a tall story" (784). According to the competition hypothesis, giraffes use their long necks to advantage during dry seasons, when food is scarce; but, in fact, the opposite is observed in the field. "In the Serengeti," Simmons and Scheepers note, "giraffe spend almost all of the dry season feeding from low Grewia bushes, while only in the wet season do they turn to tall Acacia tortillis trees, when new leaves are ...plentiful ...and no competition is expected. This behavior is contrary to the prediction that giraffe should use their feeding height to advantage at times of food scarcity" (775; emphasis added). Moreover, they report, "females spend over 50% of their time feeding with their necks horizontal [a behavior so common it is used to determine the sex of animals at a distance]" and "both sexes feed faster and most often with their necks bent" (771). These observations, they conclude, suggest "that long necks did not evolve specifically for feeding at higher levels."
Simmons and Scheepers thus reject the competition hypothesis in favor of their own sexual selection scenario. Male giraffes "fight for dominance and access to females in a unique way: by clubbing opponents with well-armored heads on long necks" (771), and thus "the extraordinary length of the giraffe's neck arises from its use as a weapon during intrasexual combat" between males. Responding to the obvious objection that this scenario does not explain female long necks, Simmons and Scheepers suggest that female necks "arose as neutral by-products of genetic correlation between the sexes" (783). While allowing that this by-product explanation "is often treated as one of 'last resort' and unsatisfactory," they argue that other species exhibit similar correlations between sexes.
Here is a nicely heretical idea to toss into the pot. Perhaps male and female giraffes have always existed with long necks--we told you it was heretical!--and they use their long necks to feed and fight, because those remarkable structures were originally available to be used. The structure is given by design; its uses follow. We leave it to your imagination to pose tests for this hypothesis. (No, we won't make the challenge easy by telling you our ideas for testing...)
L.A. Callender, "Gregor Mendel: An Opponent
of Descent with Modification," History of Science
26 (1988): pp. 41-75.
B.E. Bishop, "Mendel's Opposition to Evolution and to Darwin," Journal of Heredity 87 (1996): pp. 205-213.
According to standard histories of biology, Gregor Mendel fully supported not only the theory of common descent, but Darwinism as well. Yet, Callender and Bishop argue, a close examination of Mendel's experiments, his correspondence, and his general circumstances as an orthodox member of his monastic community jointly support a completely different reading. "Mendel was an opponent of the fundamental principle of evolution itself," argues Callender (1988, 41), "--that is to say, of "descent with modification"--and it is a striking fact that the multitude of commentators who have so consistently held that Mendel was in essential agreement with the theory of evolution has singularly failed to demonstrate in his theory of heredity any mechanism by which descent with modification might have come about." Bishop stresses that Mendel's paper shows that "he was familiar with The Origin of Species ...and he was opposed to Darwin's theory; Darwin was arguing for descent with modification through natural selection, Mendel was in favor of the orthodox doctrine of special creation."
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File Date: 5.1.97