BSC - sibling species - PSC

Richard Jensen rjensen at SAINTMARYS.EDU
Tue Nov 11 12:55:08 CST 2003

It seems obvious that two things must be shared by all viable species concepts: 1) temporal persistence and 2) some diagnostic feature. Without the former, we are left with nothing to talk about; without the latter, we don't know what we're talking about.

So, a concept (at least for sexually reproducing entities) that combines the classical BSC with a Phylogenetic SC (e.g., minimally diagnosable entities, etc.) clearly makes sense.  The two cannot exist without each other.


Barry Roth wrote:

> Matt,
> 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.
> Barry
> 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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Richard J. Jensen              | tel: 574-284-4674
Department of Biology      | fax: 574-284-4716
Saint Mary's College         | e-mail: rjensen at
Notre Dame, IN 46556    |

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