>
TG
>To the group:
>>I'm just finishing up Weiner's _The Beak of the Finch_ that describes the
>>work of Peter and Rosemary Grant in documenting rapid evolution among the
>>Galapagos finches in the wild. Now I know that some of you will dismiss
>>this work as uninteresting and unimportant on the "big" questions about
>>evolution. But I'm quite intrigued by the conclusion that ordinary
>>neo-Darwinian natural selection and divergence works on the itty-bitty
>>variations that are present and that it works very rapidly (e.g. just a few
>>generations under extremely stressful conditions).
>
SJ
>I don't think anyone disagrees with such micro-evolution, Terry. Even
>Creation-Science books that I have read believe that Darwin's finches
>came from a common ancestor. I certainly have no problem with it.
Am I a prophet or what? I suggest that you read the book. The main point
seems to be that natural selection works, that it works quickly (a few
generations) under particularly stressful times (much faster than Darwin
imagined; no need for immeasurable lengths of time as far as the Grants are
concerned), that it works to produce noticeable morphological changes, that
it works to cause divergence and specialization even among a group of
potentially interbreeding birds. Other interesting features include 1) the
point Jim Hofmann made about the role of hybrids and extremely rapid
evolution that occurs when hybrids are produced due to a reshuffling of
gene pools that were once separated and 2) that sexual selection also works
sometimes in the same direction as natural selection, sometimes against it.
>
>TG>I think that the message of the book (other examples besides the
>finches
>>are discussed) is that evolution is not slow under certain conditions and
>>that fairly traditional Darwinian principles do in fact work.
>
>Is there any need to still prove it? :-) And indeed is this really
>"evolution"?
Of course it is. There are other interesting questions that remain besides
the ones addressed here, no doubt.
>The finches still stay finches.
Has speciation occurred? Yes. The varieties become reproductively
isolated and with distinct characters. At one point Weiner commented that
the difference between the finches was as great as the differences between
chimps, humans, apes, and orangutangs. (Morphologically, I think I agree.)
>
SJ:
>I find it interesting that you are still defending "fairly traditional
>Darwinian principles" when Glenn in a recent post has chided
>"Christians" for still
>attacking Darwin's views. In the interests of clarity, perhaps you
>should take
>this up with Glenn, for the benefit of us all?
TG:
I'm reviewing a book. I'm not defending "fairly traditional Darwinian
principles". I would suggest that you read some of my earlier posts,
including my review of _Darwin on Trial_ a bit more careful. I still put
myself in the punc eq camp and am very open to there being a significant
role for developmental mutations and complexity theory as defended by
Glenn. I agree with his comments about the new synthesis emerging. But,
having said that, I'm not at all unwilling to keep whatever parts of the
old neo-Darwinian theory are true and useful. I still believe that natural
selection works; it seems pretty self-evident to me giving antibiotic
resistance and pesticide resistance and now a 20 year documentation of
evolution of finches (where by the way they banded every single bird that
lived on the islands they were studying; remarkable!). But mutation (and
the re-shuffling of genetic variety) is, and always has been for that
matter, the material source of change. Whether that mutation occurs via
small changes with small effects that are pruned by an ever watchful
natural selection as Darwined envisioned and as Dawkins still promotes
(read the book on the Finches, this is another experimental confirmation of
some of Darwin's ideas: *millimeter* differences in beak size make the
difference between the kinds of seeds a given finch can crack open) or
whether a "macromutation" occurs has the result of a key developmental
mutation or a new emergent structure that results from the fortuitous
recombination of genes (perhaps by the rare inter-species breeding observed
by the Grants), it is natural selection (and a bit of luck) that allows a
given trait to be fixed into a population.
(Don't forget, for those of you thinking about now that I have gone off the
deep end into Darwinian atheism; all of this is within a theistic context
where every mutation and every chance and contingent event is governed by
God :-)
>
>This ongoing fuzziness of debate seems to be a major feature of
>evolutionary
>argument.
Fuzziness? This seems to be a common accusation when we get to this point
in the discussion. It's not fuzzy to me at all. What's so fuzzy about it?
>I can empathise with Gould who wrote:
>
>"All these statements...are subject to recognized exceptions- and this
>imposes
>a great frustration upon anyone who would characterize the modern
>synthesis in order to criticize it." (Gould S.J., "Is a new and
>general theory of evolution emerging?", Paleobiology, vol. 6(1),
>January 1980, p120).
I like Gould's stuff, but to be honest Stephen, I think Gould's on my side
on this discussion. Gould has not thrown out Darwin or natural selection,
but rather has refined the ideas with his insights wrt punctuated
equilibrium and contingency.
Terry G.
_____________________________________________________________
Terry M. Gray, Ph.D. Department of Chemistry and Biochemistry
Calvin College 3201 Burton SE Grand Rapids, MI 40546
Office: (616) 957-7187 FAX: (616) 957-6501
Email: grayt@calvin.edu http://www.calvin.edu/~grayt