BSC - sibling species - PSC

Thomas Lammers lammers at VAXA.CIS.UWOSH.EDU
Tue Nov 11 11:56:59 CST 2003

At 09:38 AM 11/11/03 -0800, Barry Roth wrote:
>If the essays in Q. D. Wheeler & R. Meier (eds.), Species Concepts and
>Phylogenetic Theory:  a Debate.  New York:  Columbia University Press,
>2000, are any indication, then "never the twain shall meet."  Ernst Mayr's
>essay in that volume demonsted that his position on the BSC was virtually
>the same in 2000 as it was on its publication in 1940 -- a tribute either
>to the concept's robustness or the author's intransigence; maybe a bit of
>both.  The fundamental difference in approach -- the BSC states in effect
>"two [taxa] are different because they are species" while the PSC states
>"they are species because they are different" -- would make your proposal
>for a spittle of one mixed with a bit of the other a peculiar hybrid, I

It has always been my opinion that a big stumbling block in discussions of
species concepts is a lack of clarity on what exactly is meant by "definition."

In some cases, we are DEFINING in a theoretical or methodological way what
we mean by the taxonomic category called "species."

In other cases, we are looking for criteria, objective or otherwise, by
which we can determine whether some specific group of
individuals/populations should be accorded the rank of species or some
lesser rank (if any).

Though the two activities overlap and impact one another, they are NOT the
same thing.  It is conceivable that a good theoretical definition of the
category may work poorly in deciding whether black maple merits recognition
as a species distinct from sugar maple.

Thomas G. Lammers, Ph.D.

Assistant Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at
phone:      920-424-1002
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and biogeography
of the Campanulaceae s. lat.

"Today's mighty oak is yesterday's nut that stood his ground."
                                                               -- Anonymous

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