The nature of cladistics [was: Whooper; Canadian geese split; paraphyly]

Curtis Clark jcclark-lists at EARTHLINK.NET
Fri Nov 19 07:56:30 CST 2004


on 2004-11-19 07:10 Ken Kinman wrote:
> Dear All, This is the real heart of the matter.  We DO NOT invent
> paraphyletic higher taxa either.  They are just so difficult (often
> impossible) to document, due to the overwhelmingly lack of fossil
> specimens, that it is ususally just more realistic to employ
> cladistic simplification (a useful Hennigian convention, at least
> when it's not carried to excess).

Honestly, I don't have a clue what you are talking about--the situation
to me seems exactly opposite. It's easy to maintain a paraphyletic
Reptilia when the closest known relatives of birds are crocodilians, but
with all the new fossil finds, we are facing a situation where some
would claim (if I understand one of your previous posts correctly) that
Velociraptor is a bird and Tyrannosaurus is a reptile. The value of
classifying the latter, but not the former, in a major group with
turtles and cynodonts totally escapes me. What differences can
Velociraptor (or even Corvus) possibly have from Tyrannosaurus that they
would be more important than both their similarities with Tyrannosaurus
and its differences from cynodonts?



--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062




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