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From: olsen@ll-xn.ARPA (Jim Olsen)
Newsgroups: net.bio
Subject: Re: speciation
Message-ID: <344@ll-xn.ARPA>
Date: Fri, 23-May-86 12:58:36 EDT
Article-I.D.: ll-xn.344
Posted: Fri May 23 12:58:36 1986
Date-Received: Sun, 25-May-86 17:35:42 EDT
References: <7730@glacier.ARPA>
Organization: MIT Lincoln Laboratory, Lexington, MA
Lines: 16

In article <7730@glacier.ARPA>, bhayes@glacier.ARPA (Barry Hayes) writes:
> ... the division of organisms into species is fundamental, representing
> the genetic barrier of producing fertile offspring.
> 
> But one thing that has always troubled me is the arising of a new
> species from an old. ... What could do it other than two or more
> simultaneous identically placed mutations?  So what gives?
> How does it happen?  Has it ever been observed to happen?

Speciation needn't be an instantaneous process.  Consider an isolated group
of individuals of a certain species.  Genetic changes can occur and spread
through the group, so that the group can interbreed.  When the cumulative
changes are such that the group can no longer interbreed with the original
species, speciation has occurred and the group forms a new species.
-- 
Jim Olsen   ARPA:olsen@ll-xn   UUCP:{decvax,lll-crg,seismo}!ll-xn!olsen