Paraphyly and names

[Richard Pyle]

> Then I guess it still needs to be asked:  what is the point of
> doing the latter, except for trivial reasons (e.g., all
> soft-bodied taxa need to be stored in alcohol rather than on pins
> or in trays, etc.)?

The answer to your question is burried among the many previous posts to this
and related threads.  In summary: the Linnaean-based nomenclatural system
was developed before an understanding of evolution really even existed.  It
has been used with great success for two and a half centuries by biologists
in all sorts of fields. Only in the last few decades has there been any
movement towards using Linnaean-based nomenclature as a specific tool for
communicating explicit evolutionary relationships, absent all other
criteria. While we all seem to agree that polyphyly should be strictly
avoided (even early taxonomists associated bats with mammals, rather than
birds), the point of contention focuses on special cases of paraphyly, where
many biologists still find use in applying nomenclature that takes
additional factors (e.g., morphological, ecological, behavioral,
physiological) into account.  In certain cases, a particular well-defined
paraphyletic clade within an otherwise well-defined monophyletic clade has
diverged in form and function so profoundly that many biolgists feel that
overall communication is enhanced by acknowledging such divergence via the
Linnaean-based ranked nomenclatural system.

> I'm not sure why I would make a taxonomy
> unless I expected to get more out of it than I put into it.  It
> should have a predictive basis.  And because of the fact of
> organic evolution, the taxonomy that stands the best chance of
> making accurate predictions about the distribution of
> not-yet-analyzed or -discovered characters is the one most
> grounded in phylogeny.

The Linnaean-based nomenclatural system had been used successfully for many
decades by taxonomists with little or no inkling of any evolution-based
predictive value of their nomenclature.  It continued to be used without
such predictive intent for decades after Darwin as well. Now that we are at
a point in the progress of taxonomic methodology where we can make
conclusions (delusions?) about the "true" evolutionary history of organisms,
we finally have a meaningful context in which to apply some sort of
predictive value to classification.  The big question (in my mind) is
whether it makes more sense to redefine the purpose and application of a
nomenclatural system developed by a creationist two hundred and fifty years
ago to catagorize life, or whether it makes more sense to develop a new
system with the explicit, unambiguous purpose of maping the branches in the
Tree of Life -- allowing the old system to continue serving its purpose in
more or less the same way it that it always has.

Aloha,
Rich

Richard L. Pyle
Ichthyology, Bishop Museum
1525 Bernice St., Honolulu, HI 96817
Ph: (808)848-4115, Fax: (808)847-8252
email: deepreef at bishopmuseum.org
http://www.bishopmuseum.org/bishop/HBS/pylerichard.html
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