[Taxacom] Semantic Web: What is a species?

Gurcharan Singh-satyam singhg at satyam.net.in
Fri Jan 30 11:30:21 CST 2009


It is understandable to think of paraphyletic dicots and stop treating 
monocots as a distinct group; it is understandable to think of paraphyletic 
Apocynaceae and stop recognising Asclepiadaceae as a distinct family; but is 
difficult to comprehend  monophyletic or paraphyletic species. Is Taxonomy 
not getting into a great mess?

Gurcharan Singh
----- Original Message ----- 
From: "Richard Zander" <Richard.Zander at mobot.org>
To: "Kenneth Kinman" <kennethkinman at webtv.net>; <taxacom at mailman.nhm.ku.edu>
Sent: Friday, January 30, 2009 9:50 PM
Subject: Re: [Taxacom] Semantic Web: What is a species?


>I agree with Ken that species can be thought of as paraphyletic. The
> notion of reciprocal monophyly is particularly important with gradual
> speciation of two taxa from an ancestral taxon, where one of the taxa is
> at least molecularly paraphyletic to the other (different populations
> molecularly different) but becoming monophyletic as populations go
> extinct, purifying selection occurs, lots of backcrossing between
> populations of one species, and general homogenization happens.
>
> This is the Standard Theory I think among cladists, and few are
> concerned with the idea that up to half the exemplars in a study may be
> surviving ancestors of the other half.
>
> *****************************
> Richard H. Zander
> Voice: 314-577-0276
> Missouri Botanical Garden
> PO Box 299
> St. Louis, MO 63166-0299 USA
> richard.zander at mobot.org
> Web sites: http://www.mobot.org/plantscience/resbot/
> and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
> *****************************
>
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu
> [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
> Sent: Friday, January 30, 2009 9:23 AM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Semantic Web: What is a species?
>
> Hi Ilya,
>      The distinction between tokogenetic and phylogenetic is useful to
> a point.  However in reality, I believe there is a continuum of
> possibilities between strictly tokogenetic and strictly phylogenetic.
>
>
>      When a species is well on its way to dividing into two species,
> its overall population structure has shifted considerably toward the
> phylogenetic side of the continuum (but it is still just one species).
> Therefore, I think it is perfectly reasonable to think of paraphyletic
> mother species giving rise to daughter species.
>      I think it is great that Hennig got us on the road to rigorous
> cladistic "analysis". However, when it comes to translating the results
> into strictly cladistic classifications and nomenclature, it created a
> divisive and confusing mess that only continues to get worse.  And its
> most extreme manifestation (PhyloCode) hasn't even gone into effect yet.
>           ---------Ken Kinman
> --------------------------------------------------
>
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