Xref: utzoo sci.bio:5128 talk.origins:15622
Newsgroups: sci.bio,talk.origins
Path: utzoo!utgpu!lamoran
From: lamoran@gpu.utcs.utoronto.ca (L.A. Moran)
Subject: Coelacanth and evolution
Message-ID: <1991Jun7.182531.29156@gpu.utcs.utoronto.ca>
Organization: UTCS Public Access
Date: Fri, 7 Jun 1991 18:25:31 GMT


I (Larry Moran) said,

     "It is a common misconception among non-biologists that evolution is 
      associated with morphological change. Such a misconception is fostered
      by the fossil evidence that emphasizes such change."

Boris Borcic commented,

     "I am no biologist, but... isn't this a bit too dogmatic ? It is 
      certainly true that non-biologists show a bias towards a morphological-
      change view of evolution, but calling this bias a _misconception_ is
      (I feel) an unwarranted institutionalization of the bias towards the
      molecular view of all things biological of _present-day_ biologists
      (as a population)."

I hope that I'm not being dogmatic in the sense that I am advocating a belief
that is not founded on firm logical ground. In the case of evolution I am
referring to the standard textbook definition which is "a change in the 
frequency of genes in a population". Thus I claim that it is a misconception
to assume that morphological change is the only kind of evolution. If Boris
or anyone else has a problem with this then I suggest that they come up with
a better definition of evolution or at least inform the rest of us that they
do not accept the scientific definition.

Note that the definition of evolution IS molecular and that it is agreed to
by biologists who presumably should know what they are talking about. Boris,
you admit that you are no biologist and yet you claim that biologists are 
"biased" toward a molecular view. It sounds like you are saying that you know
more about biology than the biologists (otherwise you couldn't recognize the
"bias"). How do you justify such a statement?

Boris Borcic continues,

     "Molecular variation per se doesn't strike me as the only and 
      undisputable foundation for measuring an amount of evolution. Evolution
      is an ecological process as well as a molecular one, and it is not 
      obvious (to me, at least) that a measure of the evolution of a 
      particular organism/species by what is significant at the molecular
      level should be automatically congruent to a measure of the same by what 
      is significant at the ecological level."

I don't understand what you mean by "ecological process". But, as I stated 
above, you are free to create your own definition of evolution as long as
you tell us about it. We, on the other hand, don't have to agree with you!
Please tell us more about the Boris Borcic non-biologist definition of
evolution.

Boris closes with,

     "Anyway, and whatever, you can't deny that orphan species such as
      Coelocanth or Sphaenodon are a remarkable evolutionary phenomenon."

Oh yes I can! There are lots of examples, such as bacteria and single-celled
eukaryotes, that have an external morphology that has changed little in
several billion years. Look in a biology book under "stromatolites". The
only reason why Coelacanths have attracted attention is because we humans
have a bias towards those animals that are most closely related to ourselves.
Or towards animals that are bigger than a breadbox.

My own personal favorite among organisms that exhibit some "primitive"
characteristics is Pelomyxa palustris, a single-celled eukaryote that shares
some of the characteristics of the first eukaryotes. These characteristics
are over one billion years old. Sorta puts coelacanths to shame doesn't it!

-Larry Moran

PS Don't worry about your English - it's excellent. Most of us can't write
   any better even though we learned English as a first language. Even after
   four years of living in Geneva I still couldn't communicate effectively in
   French, you should be proud.