species & subspecies concepts (a summary?)

[Ken Kinman]

     A lot of important points have been made about species concepts and
subspecies concepts in the past couple of weeks.  I personally think Martin
Dube' (I hope I spelled his name correctly) hit the nail right on the head
when he said something to the effect that:  species are the least arbitrary
of taxonomic constructs.
     I think Stanley Miller was right to the extent that endlessly arguing
over a single, all-encompassing definition of anything is largely a waste of
time after it has been bandied about for a while.
     I think this discussion has clearly demonstrated that neither the
phylogenetic or biological species concepts have "cornered the market" on
either truth, desirability, or practicality.  The BSC is only practical in
very well-studied taxa, and can't be used for asexual organisms, but since a
majority of species are sexual, I still believe the BSC is what we should
aspire to, even if we obviously do not have the resources to study most taxa
in such depth.
     As for subspecies, they too seem to be most useful in well-studied
groups, but each biologist must decide if formally-named subspecies are
useful for his or her particular group.  And although sympatric subspecies
are more the exception than the rule, they can be said not to exist only if
you have a rather restricted definition of sympatry.  In summary, different
strokes for different folks.  To state or imply that "species are absolutely
objective" and that "all other taxa are absolutely subjective" ignores the
continuity of the evolutionary process.  Even if species are much less
arbitrary than others, the arbitrariness will always be there (especially
when the time dimension is taken into account).  But I believe that the
"arbitrariness" of delimiting species is at a low enough level that they can
be usefully regarded as "individuals", as Ghiselin and Hull have explained
in their papers on that subject.
                        -----Ken Kinman

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