|
|
  
Access Research Network
Literature Survey
Origins & Design 18:1
Paul Nelson
T.H. Huxley's Ambivalence
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.
The Neck of the Giraffe
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...)
Mendel's Opposition to Darwin and Evolution
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."
Copyright © 1997 Paul Nelson. All rights
reserved. International copyright secured.
File Date: 5.1.97
This article provided by Access Research Network.
Access Research Network is a non-profit 501(c)(3) organization dedicated to providing
accessible information on science, technology and society.
Access Research Network
PO Box 38069
Colorado Springs, CO 80937-8069
Phone: 719-633-1772
Email: info@arn.org
www.arn.org
Email this to a friend
copyright
© 1995-2008
Leadership U. All rights reserved.
Updated: 14 July 2002
|