Farewell to Species - reticulation

[Curtis Clark]

At 10:43 AM 00.02.02 -0500, Thomas DiBenedetto wrote:
>I would say that we have two species, but three taxa. The original species
>should not be "relegated to nomenclatural extinction", but recognized as a
>higher taxon. My view of a taxon is that it represents a lineage (branch,
>or
>system of branches)emanating from a common ancestor. The original taxon
>still exists, and will continue to exist until all of its descendants are
>extinct. The original taxon is, however, more complex than a simple
lineage
>branch; that original single branch has given off a sublineage. [...]

>From a genetic standpoint, this is ludicrous. In many groups (e.g. annual
plants), species form peripheral isolates all the time. Only occasionally
do these become new species. To suggest that a taxonomic system should
treat the ancestral species differently depending on whether peripatric
speciation succeeded or failed effectively removes the system from the
realm of real-world events. I'm no anti-cladist (Kinman has accused me of
being a radical cladist), and I am a firm advocate of monophyletic higher
taxa, but IMO shoehorning observed biology into a system that misrepresents
it is on a par with accepting paraphyletic groups just because they are
"grades".


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Curtis Clark                  http://www.csupomona.edu/~jcclark/
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