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Re: The validity of cladograms (was Re: giant birds)



Stanley Friesen wrote:
> 
> At 04:50 PM 11/14/99 -0600, chris brochu wrote:
> >You seem to be saying that because we can't (yet) achieve perfect
> >resolution in our phylogenetic summaries, something is seriously wrong.
> >...  This is why I thought Paul Sereno's
> >method for summarizing different theropod hypotheses, in which he
> >constructed a strict consensus of different trees, was not appropriate -
> >his tree was very poorly resolved, but in fact there are less sensative
> >consensus methods available that would preserve the resolution found in
> >common with most published analyses.
> 
> Quite so.  This is why I prefer majority consensus, or some similar method.


Majority-rules consensus can be *VERY* biased, and very few editors
would ever allow one to be published as a primary summary of
relationships, except perhaps to summarize a bootstrap result.  I happen
to endorse this dim view of majority-rules consensus.  The only place I
still see MR consensus used is in invertebrate paleontology, where the
practice will hopefully die soon.

But Adams consensus is another matter - it draws "rogue taxa" down to
their lowest common node.  As long as a strict tree is also shown, this
can be a powerful way to boost resolution.  Mark Wilkinson has also
devised some additional methods, which I haven't explored.


chris
-- 
----------------------
Christopher A. Brochu
Department of Geology
Field Museum of Natural History
Roosevelt Road at Lake Shore Drive
Chicago, IL 60605

voice: 312-665-7633  (NEW)
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electronic:  cbrochu@fmppr.fmnh.org