[Taxacom] orangtuans and human origins

Steve Manning sdmanning at asub.edu
Mon Nov 3 09:11:35 CST 2008


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
>
>
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