species/subspecies query

Ken Kinman kinman at HOTMAIL.COM
Thu Nov 16 05:16:53 CST 2000


Curtis,
     Well, it's my bedtime, so maybe my brain just isn't understanding what
you are getting at.  I never said that the potential for genetic exchange
was more important than actual genetic exchange.  But different populations
of a species can be isolated from one another for significant periods of
time without incompatibility (isolating mechanisms) developing.  Actual
genetic exchange is necessary to maintain the cohesiveness of a species over
the long term, but it certainly need not be continuous exchange.
      And I certainly have the utmost respect for species and speciation.
On the contrary, I think it is the phylogenetic species concept which often
fails to give the proper respect to species and speciation, especially in
its tendency to simplistically assume that allopatric subspecies are full
species because of the slightest differences and the fact that there are not
currently any exchanges between their gene pools.  Perhaps you are
underestimating the cohesiveness of species and just how difficult it is to
permanently and irreversibly establish isolating mechanisms.  And I would
certainly disagree with your assessment of just which side is "making up
stories".
                        ------Ken Kinman
********************************************************
>From: Curtis Clark <jcclark at CSUPOMONA.EDU>
>Reply-To: Curtis Clark <jcclark at CSUPOMONA.EDU>
>To: TAXACOM at USOBI.ORG
>Subject: Re: species/subspecies query
>Date: Wed, 15 Nov 2000 19:44:22 -0800
>
>At 08:07 AM 11/15/00, Ken Kinman wrote:
>>As long as there is the potential for genetic exchange between
>>populations A & C by way of the intermediate population B, it seems
>>preferable to regard it as one species which is in the process of
>>speciation.
>
>That's why species and speciation don't get any respect: it's all too easy
>to make up stories about them. "Potential for genetic exchange" becomes
>more important than actual genetic exchange, and its consequences for the
>organisms. "The process of speciation" can be invoked as an explanation
>even before there is any actual evidence that speciation is occurring. It's
>really not any better than "How the Elephant Got Its Trunk".
>
>IMO there are only two legitimate positions: (1) Species are not actual
>units of nature, and so species concepts are hollow rhetoric and speciation
>is not a real process; (2) Species are units of nature that originate
>through a process or processes that we call speciation, and we can
>formulate testable hypotheses that help us to understand both the processes
>and their products.
>
>
>--
>Curtis Clark                  http://www.csupomona.edu/~jcclark/
>Biological Sciences Department             Voice: (909) 869-4062
>California State Polytechnic University      FAX: (909) 869-4078
>Pomona CA 91768-4032  USA                  jcclark at csupomona.edu
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