BSC - sibling species - PSC

Barry Roth barry_roth at YAHOO.COM
Tue Nov 11 09:38:58 CST 2003


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 believe.


Matt Buys <BuysMH at PUKNET.PUK.AC.ZA> wrote:
Hi all

Two questions:

1. One of Ernst Mayr's objections to the phylogenetic species concept
is its failure to recognise so-called sibling species which by
definition look identical externally. In the light of advances in the
molecular field, is there published research on whether two sibling
species that look identical externally can be grouped into two taxa
based on molecular evidence?

2. The BSC has to do with the ability to reproduce. The phylogenetic
species concept (PSC) is based on the possession of unique characters.

All individuals resulting from sexual reproduction are however unique
(at least at the molecular level). So as I see it, to be a species, you
have to possess characters that are unique (enter the PSC) to a
population or group of populations, implying some form of gene flow
(enter the BSC), but not unique to an individual. So, can I submit to a
species concept for sexually reproducing organisms consisting of dual
elements, viz. a spittle of BSC mixed with a bit of PSC?

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