Re: Evolution: A few questions

On Tue, 22 Jun 2004 20:02:04 -0400 "Mike Tharp" <mtharp@exammaster.com>
writes:
> Hello Dave,
>
> Just out of curiosity, how would one account for the evolution of
> the
> metamorphosis process of animals such as frogs and butterflies? It
> has
> always seemed improbable to me that such an elaborate process could
> have
> evolved due to natural selection for random genetic mistakes.
> However, I
> readily admit that this is a topic in which I am utterly ignorant!
> Perhaps
> you would be willing to share your insights?
>
> In Christ,
> Mike
>
Mike,
The simple answer is "I don't know." I am neither a herpetologist nor a
lepidopterist nor a paleontologist, the specialties that would, at the
moment, have as much relevant information as any. Additionally, the
questions you raise will have to be answered by a study of comparative
genomics. However, I do not know of any amphibian that has been
sequenced. I think one of the Drosophila has been sequenced, but that is
very preliminary to figuring out how the flies undergo development
compared to other creatures which undergo various levels of metamorphosis
and those that develop more directly. What I have run across is that
changes in /hox/ sequences, genes strung together that are activated
sequentially during development, can produce major alterations in
embryonic development in chordates, as well as during the development
both of the embryo and of the pupa in insects. But how they are activated
and how often, I do not have the expertise to follow.

While you profess to be "utterly ignorant" of such matters, you know
enough to present a very slanted version of evolution. "It has always
seemed improbable to me that such an elaborate process could have evolved
due to natural selection for random genetic mistakes," misrepresents
evolution prejudicially. The proper term for development using only
"natural selection for random genetic mistakes," is "impossible." The
simple fact that there are more /hox/ sequences in mammals than in flies
demonstrates that "random genetic mistakes" is not descriptive of the
transformation of simpler to more complex forms. This is only one of the
types of alteration available. But that has already been noted earlier in
this sequence of posts.

By the way, your final sentence is a bit of /ad hominem/ nastiness. I
have not responded in kind. However, while I was teaching, the other
logic professors assigned my letters to the editor as exercises in
recognizing loaded language. Need more be said?
Dave
Received on Tue Jun 22 23:51:03 2004