Real species and ideology

[Curtis Clark]

At 16:50 2004-04-19, Ken Kinman wrote:
>       I think phylogenetic species concepts are ill-advised.

I hate it when I agree with Ken :-), but in this case, I do. At least in
plants, speciation by peripheral isolation results in "parphyletic"
ancestral species that continue to exist contemporaneous with their
derivatives, and having (at least in theory) no apomorphies of their own.
Another example of the value of studying process before codifying "species
concepts".

Also in plants, subspecies (or varieties; the terms are effectively
interchangeable in most cases despite the Code distinguishing them) often
represent seemingly permanent geographic variants, often connected by
morphoclines, that don't appear to be "on the way to speciation", even
though of course their variation could potentially be the raw material for
speciation. It is often a non-trivial task to distinguish between two
subspecies separated by a morphocline, on the one hand, and two species
separated by an area of introgressive hybridization, on the other, but
genetic tools can often be brought to bear to sort out these issues. (It
especially helps if the two intergrading species turn out not to be sister
species!)


--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062