Xref: utzoo sci.bio:5170 talk.origins:15831
Newsgroups: sci.bio,talk.origins
Path: utzoo!utgpu!lamoran
From: lamoran@gpu.utcs.utoronto.ca (L.A. Moran)
Subject: Coelacanth and Evolution
Message-ID: <1991Jun14.041331.16815@gpu.utcs.utoronto.ca>
Organization: UTCS Public Access
Date: Fri, 14 Jun 1991 04:13:31 GMT


I (Larry Moran) said,

     "There are several better ways of explaining why a favorable allele 
      may not become fixed in a population."

and Jorn Barger replied,

     "Fer instance? I'm perplexed at what appears to me a monolithic front
      claiming in effect "there is no mystery to be explained here". Darwin
      expected a gradual blending of morphologies. Of course there will
      always be amino acid substitutions, but why in some species is the 
      morphology so static?"

Favorable alleles can be lost by chance in a population before they become
fixed. This chance occurence is part of one of the main mechanisms of
evolution; random genetic drift. Examples could be the accidental destruction
of the group of organisms that contain the favorable allele or loss due
to the fact that chromosomes are segregated during meiosis and not all
combinations are passed on to the next generation.

A favorable allele may also be linked to one which is selected against in
a given population. The net effect might be to eliminate both alleles.

Jorn, I think that you have read enough in these newsgroups to realize that
Darwin's ideas are not particularly relevant to modern thought on evolution.
It is not useful to quote Darwin, especially when you are attacking his
position. Most of us agree with you that Darwin's position on a lot of things
was wrong or incomplete.

The reason why morphology may not change drastically over a long period of 
time should be fairly obvious. Several others have mentioned it here. If
an organism is well adapted, morphologically, to a particular environment
then most mutations in "morphology" genes will have negative fitness. They
will not become fixed in the population and the morphology will not change.
In some cases new structures might arise in part of the population and this
group could evolve in a different direction (with substantial change in
morphology).

There is no mystery to be explained here.

Jorn Barger also says,

     "I'm not especially in the thick of biology these days. Philosophically,
      though, I think it's always important in the sciences to spend a good
      amount of thought on the farthest-out hypotheses imaginable, just so 
      as not to fall into the narrow traps of scientific pride."

I agree with you. The problem is that amateurs resent it when experts shoot
down their far-out hypotheses on scientific grounds. These amateurs then
start complaining about the science mafia and how bigoted we all are. What
amazes me is the hubris of some of those amateurs who post to talk.origins 
and sci.bio. They seem to assume that they have some insight into evolution
that has never occurred to "narrow-minded" biologists even though these same
biologists have been studying evolution full time for 200 years. Give us a
little credit, eh!

-Laurence A. Moran