[Taxacom] orangtuans and human origins

John Grehan jgrehan at sciencebuff.org
Mon Nov 3 09:17:06 CST 2008


Unfortunately I don't know if this is even possible, let along
demonstrate that any character was selected for (in the natural
selection model) in its origin. Our position is that there is no recipe
for anyone to decide between contradictory morphological and molecular
data. But our position is also that there is no necessary empirical
reason why molecular data, even if the same result comes from different
genes, should have priority over morphological data giving a different
pattern of relationship.

We will most likely give examples of several problematic aspects of
molecular analysis to give one reason as to why one might personally
decide in favor of a robust morphological pattern of relationship -
should one chose to.

John Grehan



> -----Original Message-----
> From: Steve Manning [mailto:sdmanning at asub.edu]
> Sent: Monday, November 03, 2008 10:12 AM
> To: John Grehan; TAXACOM
> Subject: Re: [Taxacom] orangtuans and human origins
> 
> I would suggest as a reason why you might prefer morphological
> characters to genetic ones is if you can demonstrate likelihood that
> any of the morphological characters are/were "strongly selected" at
> and following the time of divergence - either based on paleoclimates,
> biogeography, or known other biota at the time.
> 
> Steve Manning
> 
>   At 07:53 PM 11/1/2008, John Grehan wrote:
> >I kindly received some pertinent comments off list. I feel they are
of
> >general interest in relation to the issues I am confronted with and
so I
> >am responding on the list, but without the person being named since I
> >presume privacy was preferred.
> >
> >Dear John,
> >
> >  >  Having just been to the Hennig-meeting in Tucuman I can assure
you
> >too (as did Jim Croft) that morphological analysis is not dead, and
was
> >
> > >  an important element in many of the papers presented there
> >
> >But does morphology represent an important element if it is
subordinated
> >to molecular similarity? That's the problem in primate systematics,
not
> >only for the human-orangutan/African ape problem, but also the
tarsier
> >vs anthropoid or prosimian problem, and the cheirogaleid lemur vs
other
> >Madagascan lemurs or lorisiforms. In each case the argument made is
that
> >the molecular results must be right and the morphology must be wrong.
If
> >morphological systematics is wrong simply because it is not supported
by
> >DNA molecular similarity then morphological systematics is not longer
a
> >science. Rather it is a fantasy. That's the implication that everyone
> >dances around. It amazes me how many morphologists are subservient to
> >molecular similarity. It seems that they have no concern that this
> >position makes nonsense of their discipline (ironically I met one
> >paleoanthropologist who admitted that there was no longer reason to
> >employ morphological systematists).
> >
> > > (although most people found that the results were roughly
congruent
> >with the molecular analyses, if they could compare them).
> >
> >Where there is incongruence of some parts, does that mean the
congruence
> >of other parts is still informative?
> >
> >  One particular point that absolutely requires the consideration of
> >morphological data is, of course (as was pointed out a number of
times)
> >the inclusion of fossils in an analysis.
> >
> >But if only molecular similarity can be relied upon to give the
correct
> >answer then the entire fossil record is uninformative and
scientifically
> >meaningless because there is no way to scientifically know what the
> >fossils are in the absence of molecules to tell you.
> >
> >I would suggest that you firmly stick to that point, and try to deal
> >with the discrepancies as points that are interesting, but not
> >particularly alarming. There should be no reason to accuse you of
> >"reliance" if you merely point out what the data make you infer...
> >
> >We did that, but the editors want us to give them some reasons why
the
> >molecular result may be wrong (whether or not it is in this
particular
> >case) even if different genes give the same answer.
> >
> >John Grehan
> >
> >
> >_______________________________________________
> >Taxacom mailing list
> >Taxacom at mailman.nhm.ku.edu
> >http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> 





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