On Fri, 16 Jun 1995, Dennis Paulson wrote:
> Chris, I wonder if you would agree with me that splitting is a fad right
^^^
Ahem, Dennis, I think the term you are looking for here is "paradigm shift"...

> now (because of a reassessment of species concepts, rather than
> arbitrariness), just like lumping was a fad some decades ago (for the *very
> same reason*). Bob Zink and other proponents of the PSC concept, much as I
> respect them and their work, are merely pursuing vigorously an alternative
> hypothesis that could even be called a "bandwagon," the "truth" of which is
> no more apparent than that of the BSC. I suppose we could argue clines vs.

Choosing between reproductive isolation (the basis of the BSC) and
demonstrated divergence (the basis of the PSC) is indeed a matter of
preference: each is defendable as the basis for distinguishing species.
But as I mentioned in a previous message, the BSC has big problems even if
you choose reproductive isolation as the most important aspect of
speciation. These problems with the BSC were not recognized by its
architects because they simply were not all that concerned with genealogic
relationships *among* species. That, of course, is at the heart of
the cladistic revolution, and it is this revolution that led to critical
reappraisal of the BSC. If the BSC was revamped so that it did not
produce genealogically nonsensical species, it would look a lot like a PSC
that takes into account population genetics (cf. Donoghue's version of
the PSC), and a lot like Wiley's ESC. Everything that rises must converge.

David Wright
dwright at u.washington.edu