Exist sub-species?

[Panza, Robin]

Oh, please don't hit me with "gene frequencies"! Sorry for the knee-jerk
response, but I have heard that term used (or abused) in some pretty strange
ways--like declaring two populations to be evolutionarily distinct based on
differences in the frequency of a few alleles, even though neither has any
unique alleles. The "Gene Flow Species Concept" (GFSC) as I envision it is
that if one has a reasonably pronounced step cline geographically (for
genotypes or phenotypes), then one has *evidence* for what I consider
subspecies.  A smooth cline would be variation that cannot be *described* by
any species concept of which I'm aware.  A near-perfect step defines two
species.  By the way, I don't know of any published explanation or use of
the term GFSC.  I made that up all by my lonesome.

All that said, I should explain that my species concept is based on
"evolutionarily distinct" populations (EDPSC?).  This is my pop. gen. past.
I use gene flow as a measure of evolutionary distinctness.

just a couple more cents,
Robin

Robin K Panza                  panzar at carnegiemuseums.org
Collection Manager, Section of Birds      ph:  412-622-3255
Carnegie Museum of Natural History       fax: 412-622-8837
4400 Forbes Ave.
Pittsburgh  PA  15213-4080  USA

Byron wrote:
>The other methods of describing variability that I referred to
>as being more descriptive and less arbitrary are those employed by
>population biologists/geneticists.  I am not a pop gen person, but I think
>their use of gene frequencies (for example) to describe intraspecific
>variation carries more meaningful information than the term "sub-species"
>(you seem to argue for this notion yourself, given your previous post about
>"sub-species" and gene flow).  Gene frequencies (or the frequencies of
>other quantitative traits for that matter), tell us exactly how much
>variation exists.  The term "sub-species" only tells us "some kind of
>intraspecific variation exists."