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Re: Another Branch of the Family



At 06:22 PM 6/18/00 -0400, philidor11 wrote:
From a review by W. Ford Doolittle of the book by Colin Tudge, Sunday (6/18) New York Times Book Review Section:
Either we call birds reptiles or
we cannot have such a group as the class Reptilia, because it spawned
creatures (in fact two whole classes, Aves and Mammalia) that we don't
call reptiles. Disputes about this still rage in the academic
literature because there are still those who hold that similarity, if
strong enough, should trump relationship,

I find this wording of the issue to be prejudicial and, IMHO, inaccurate. Allowing paraphyletic groups does NOT override relationships, and no modern taxonomist that I know of would tolerate a truly polyphyletic group, no matter how great the similarity. (A paraphyletic group is still a closed figure with regard to the evolutionary tree, so relationships still dominate).


What IS suggested is that similarity should be a strong *secondary* factor in determining classification. Nobody since the demise of Numerical Taxonomy has seriously supported any other position.

 that classification is not
          just about genealogy.

This, however, is what the real issue is.

Tudge explicates the cladist doctrine quite clearly, while personally
adopting an intermediate position (suggesting that we simultaneously
recognize a Reptilia that includes mammals and birds and a
''Reptilia'' that doesn't, and would be what most people mean by
reptiles). This is the kind of casual ambiguity with which most of us
are already comfortable -- without the typographical trickery. I doubt
that Tudge's terminology will be embraced by professionals.

So do I. I would use Reptilia for a paraphyletic grouping closely corresponding to its classical scope.


--------------
May the peace of God be with you.         sarima@ix.netcom.com