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RE: Definitions



>Firstly, I want to point out that stem- and node-based taxon definitions are
>part of phylogenetic taxonomic nomenclature (in other words, a particular
>scheme for labelling parts of the tree of life).  This is not exactly the
>same thing as cladistics, or phylogenetic systematics.  The latter is a
>methodology for estimating patterns of shared common ancestry (that is,
>attempting to reconstruct the shape of the tree of life).
>


As a further clarification, "cladistics" has been used in the literature
for two different things - a methodology for estimating relationships
(parsimony) and the recognition of monophyletic groups and only
monophyletic groups in taxonomy.  One can apply some other method
(likelihood, for example) and still be a strict cladist with respect to
taxonomy (or to phylogenetic nomenclature, which is the placing of
phylogenetically-defined names on the taxa we recognize).

Unfortunately, we still see people in the literature confusing the two.
Have a look at Vermeij's response to his flotilla of criticisms for an
example of what should not be happening anymore.



chris

------------------------
Christopher A. Brochu
Assistant Professor
Department of Geoscience
University of Iowa
Iowa City, IA 52242

christopher-brochu@uiowa.edu
319-353-1808 phone
319-335-1821 fax