Re: Species [ was: Re: Hadrosaur nomenclature]

[Graydon <graydon@dsl.ca>]

On Thu, Oct 18, 2001 at 09:32:35PM -0400, T. Mike Keesey scripsit:
> On Thu, 18 Oct 2001, Graydon wrote:
> > A species is a population where there is no genetic restriction to the
> > degree of the common descent among the next generation from any member
> > of the species -- they can all mate effectively with each other, given
> > the opportunity.
> 
> What about asexual organisms?

You can get rid of the clause about 'mate'.

If we're going to stick to multi-cellular life -- which I think is a
good thing, since unicellular life doesn't restrict genetic exchange to
reproductive activity, and changes the cases -- the asexual organisms
are few and far between, as well; parthogenetic lizards are still a
species by that definition, since any of them will produce the same next
generation.

The idea of species in terms of when genes can travel through the
*future* population isn't perfect, but it's pretty robust.  Can organism
A and organism B have common descent?  (without technological
intervention; I don't want to argue for fireflies and tomato plants as
cospecifics!)  If they can, they're in the same species.

-- 
                           graydon@dsl.ca
               To maintain the end is to uphold the means.