Group: sci.bio.evolution · Group Profile
Author: Tim TylerTim Tyler Date: Nov 8, 2007 10:27
The Last Conformist wrote:
> On Nov 7, 4:35 am, Tim Tyler cyberspace.org> wrote:>> The Last Conformist wrote:
>>> On Nov 5, 7:21 pm, nos...@ nospam.com (Paul Ciszek) wrote: >>>> The hits I get on "extinct phylum" all point to Stephen Jay Gould's
>>>> "Wonderful Life" view of the Burgess Shale. Others, who disagree with
>>>> Gould, put the Burgess Shale "weird wonders" into Arthropoda or
>>>> Onchyphora, eliminating the need for separate extinct phyla.
>>> There is no such thing as a need for a separate phylum. What rank we
>>> grant to taxa (above species) is arbitrary.
>
> And? There are no objective way to tell whether two similar groups
> have variants of the same "general body plan" or exhibit two similar
> "general body plans".
Use of the term "arbitrary" suggests there are no classification
rules at all. I think that is not correct. There may well
be cases where whether two organisms share the same general body
plan or not is debatable - but there are plenty of cases where
there is no debate because the differences are obvious.
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