Re: Limits of Kinds
Scott A. Oakman (oakma001@maroon.tc.umn.edu)
Tue, 11 Nov 97 09:05:49 -0600Glenn Morton wrote:
> At 10:19 PM 11/10/97 -0600, bpayne@voyageronline.net wrote:
>
> >Speaking of inconsistent, I have a question. Supposing we grant you
> >evolution of everything from simple to complex. Then what would cause
> >some species to drop out of the race? For example, horseshoe crabs
> >still look like they did in the Cambrian (?). If the horseshoe crabs
> >evolved along with everything else up to their present form, why did
> >they suddenly put the brakes on and remain unchanged (stasis) for 600
> >million years while everybody else kept racing onward and upward? Are
> >the crabs immune to mutations? Are you being consistent, my friend?
>
> First off, they didn't stop changing. Horseshoe crabs do NOT look the same
> today as they did in the Permian. Go see Moore, Laliker and Fischer,
> Invertebrate Paleontology I forget the page. The permian horseshoe crab is
> a whole lot different from those you pick up on the east coast today. It has
> its shell swept outward today's is an ovoid form. The Jurassic was almost
> circular in shape. In fact, not a single "living fossil" that I have
> investigated is the same as what is alive today. This includes ginkgoes,
> coelecanth and all the others. What the anti-evolutionists are doing is
> saying that the ginkgoes look like today. Well ginkgo is a genus, not a
> species. This is like saying that there were trees in the Pennsylvanian
> thus trees have remained unchanged over that time. They use a high
> hierachical category to make the claim.
I think it should also be pointed out that Mr. Payne is appealing to a popular
fallacy that Evolution=Progressivism. (And by popular, I mean to convey that
that is how just about everybody thinks of it in the lay world.) Progressivists
may well put this philisophical "onward and upward" spin on evolution, or use
evolution as support for their philosophical biases, but progressivism is not a
necessary precept of biological evolution. A "picture" of evolution might be
more one of "onward and OUTward"--with adaptations filling ecological niches,
than "onward and upward" with successive generations "improving on previous
models". If an animal is well adapted to fill a stable ecological niche, it
very well might not be seen to continually evolve.
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Scott Oakman Graduate Program in Neuroscience
University of Minnesota MD/PhD Program
oakma001@maroon.tc.umn.edu
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