paraphyly

Bengt Oxelman bengt.oxelman at SYSTBOT.GU.SE
Thu Jun 12 22:00:23 CDT 1997


>At 10:52 AM 06-12-97 -0700, Barbara Ertter wrote:
>
>>It's not a question of the existence of paraphyly, but rather whether it i=
s
>>a mortal sin as far as nomenclature is concerned.  Why is it anathema to
>>have taxon A arising from the middle of taxon B?  Isn't it likely that thi=
s
>>is exactly how evolution works?
>
>Exactly!  "Budding off" of peripheral isolates is extremely common mode of
>allopatric speciation.  When it happens, a formerly monophyletic species
>becomes paraphyletic.

This is nonsense and the result of a confusion of species as taxa (Linnean
categories) and species as evolutionary units. With this reasoning there
would be no monophyletic taxa at all. For example evolution in the genus
Mus would make Eucaryota paraphyletic. Species as evolutionary units is the
very singularity that changes in our evolutionary model. Hence, monophyly
is not a relevant concept.

Bengt

--------------------------------------------------------------------------
Bengt Oxelman
Department of Botany
Stockholm University
Lilla Frescativ=E4gen 5
S-106 91
Sweden

Phone: +46 8 161215
=46ax: +46 8 165525
Internet e-mail: bengt.oxelman at systbot.gu.se




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