Newsgroups: sci.bio
Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!alchemy.chem.utoronto.ca!mroussel
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: non-genetic evolution... not
Message-ID: <1991Apr25.203311.20957@alchemy.chem.utoronto.ca>
Organization: Department of Chemistry, University of Toronto
References: <79788@bu.edu.bu.edu> <47570@ut-emx.uucp> <79798@bu.edu.bu.edu>
Date: Thu, 25 Apr 1991 20:33:11 GMT

In article <79798@bu.edu.bu.edu> colby@bu-bio.UUCP (Chris Colby) writes:
>	Remember that evolution is _defined_ as a change in the
>gene pool; therefore non-genetic evolution is by definition non-
>sensical.

     I'm not a biologist so I hope that what I'm about to write isn't total
nonsense.  If it is, reply by email and I will post a retraction with a
summary of the points people have made.  If not, we can debate things in
this forum.
     It seems to me that the definition presented above is useful in some
contexts, but overly restrictive in others.  The wasp example which
someone else posted is a good example.  Whether or not the wasps' gene
pool changed, there has been a change in the species which is persistent
against (one presumes) significant external perturbations.  It seems to
me that this qualifies as evolution in a less restricted sense than the
current dogma allows: a species can be said to have evolved a trait if
this trait is transmissible from generation to generation and stable
against reasonable environmental perturbations.  (I will let someone
else define "reasonable" and "external environment", if any of this makes sense.
Surely in the case of the wasps and their symbiotic partners, the
symbionts form one system and thus are not part of the external
environment.)  This definition of course excludes (quite rightly) trivial
cases like the "better nutrition = taller humans" effect which Chris mentioned.
     My definition has the advantage that it allows us to include in
evolutionary theory things which we may not have thought of yet.
Further, stability of evolved traits as the hallmark of evolution brings
the language of biology into line with modern thinking in other sciences.
(I am curious to hear comments on this last point.  Would people
think of this as an advantage, a disadvantage, or neither?)
     I look forward to your comments.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca