Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!cernvax!chx400!ugun2b!cuisun!borbor
From: borbor@cuisun.unige.ch (BORIS Borcic)
Newsgroups: sci.bio
Subject: Molecular vs Ecological Evolution (was Re: Coelacanth and evolution
Message-ID: <5699@cuisun.unige.ch>
Date: 6 Jun 91 16:53:24 GMT
References: <1991Jun4.164709.431@gpu.utcs.utoronto.ca>
Reply-To: borbor@un2sun42.UUCP (BORIS Borcic)
Followup-To: sci.bio,talk.origins
Organization: University of Geneva, Switzerland
Lines: 46

In article <1991Jun4.164709.431@gpu.utcs.utoronto.ca> lamoran@gpu.utcs.utoronto.ca (L.A. Moran) writes:
> [...]
>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. 
>

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).

Molecular variation per se doesn't strike me as the only and undisputable fundation 
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.

As a matter of fact, the human species is a counter-example of one type (e.g.
very little evolution at the molecular level in, say, 5000 years, but a very
significant one as an ecological actor). So-called living fossils could be
counter-examples of the other kind - significant molecular evolution, but
(perhaps) little evolution as ecological actors.

Software engineering distinguishes between interface and implementation.
Both can evolve independently (Well.. one can't really change the interface
without changing _anything_ to the implementation, but never mind). Some
similar dichotomy could be used in evolution theory, if I may humbly suggest.
(It would be parent but not identical to the genotype/phenotype dichotomy,
since a selectively neutral variation to an expressed protein counts as
a difference in phenotype but should not count as a difference of
"ecological interface").

Of course single molecular changes with no morphological impact can play
very significant ecological roles, most often with plants, also with
animals - but isn't it the case with the latter that morphology _is_
quite sensitive to a change of niche ?

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

B. Borcic - borbor@divsun.unige.ch

(... and please excuse the awkward English)