[Taxacom] cladistics (was: clique analysis in textbooks)
Richard.Zander at mobot.org
Wed Aug 17 11:58:01 CDT 2011
Again, I suggest that morphological clades and molecular clades can be different because they are based on different dimensions in present-day relationships of evolution, thus the refutation of one clade cannot be done by finding high probability that the other is correct.
Morphologically you can have ((AB)C,D and molecularly ((AC)B,D, and both are correct if the morphological ancestor of both A and B is C.
C is then postulated as a morphologically primitive taxon surviving into present time after generating the geographic isolate B then A. This difference in clades is because DNA continues to mutate but the morphology can remain in stasis.
Molecular analysis cannot refute or reject the orangutan-homo morphological evolutionary relationship, assuming the morphological relationship has been demonstrated by Grehan and Swartz, et al. A direct analysis, using other data, that might reveal the morphology of the ancestor of both man and whatever the sister group in morphology is, is necessary. The present argument is just talking past each other, and both analyses, if taken separately, are each sciolistic, that is, based on only partial knowledge.
Richard H. Zander
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166 U.S.A.
richard.zander at mobot.org
From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Kenneth Kinman
Sent: Tue 8/16/2011 9:49 PM
To: taxacom at mailman.nhm.ku.edu
Subject: [Taxacom] cladistics (was: clique analysis in textbooks)
Gee, I am a fan of cladistic analysis (if done correctly), but I
never thought that ANY form of cladistics was "necessarily" correct (but
a lot that seemed better than John's, although admittedly I have seen
some that were worse, even at higher taxonomic levels, and thus more
detrimental and regretably sometimes accepted by far too many).
As for some people having used "refuted" as a synonym of
"rejected", whoever they might be, I really doubt that they are
restricted to users of US language (as opposed to English language as a
whole or even other languages). In any case, I predict an exclusive
orangutan-hominid clade will continue to be both refuted and rejected.
It has very clearly been "rejected" by the vast majority, but a small
minority still insists that it has not been "refuted". Anyway, I'm not
going to lose any sleep over that one, but I am admittedly still
bothered by the question of whether chimps clade exclusively with
gorillas or with hominids. Hopefully we will see some more informative
papers on that subject in the near future.
------a user of "US language",
John Grehan wrote:
Yes I am asserting that 'my' form of cladistics is necessarily
correct - or at least more correct or better than some others. And I
realize that I am sticking my neck out on that and perhaps setting
myself up for a fall - in which case the orangutan evidence will not
doubt be refuted (and I am not using that term as a synonym of rejected
as often occurs in US language).
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