[Taxacom] hominid evidence

Dr. David Campbell amblema at bama.ua.edu
Tue Jun 30 11:03:24 CDT 2009


> it seems obvious that both morphological characters and DNA bases
> are... characters. Each being one "evidence" as such.<

Additionally, both are subject to potential sources of error (in regard 
to their pointing to the correct phylogeny) such as convergence, random 
similarity, shared ancestral features, researcher error, etc.  There 
are indubitably molecular data that favor a human-orang grouping and 
some that would favor a chimp-orang grouping, just as there are 
morphological and behavioral features that support a chimp-human or 
chimp-orang grouping.  (As this concerns a small cluster of highly 
derived deuterostomes rather than more interesting lophotrochozoans, I 
have not followed the details very closely, but an obvious 
morphological link for humans to chimps and gorillas is hair and skin 
color; in behavior, there's the new study of tickle-induced laughter.)

This isn't really a morphology versus molecules issue (though the fact 
that people can specialize in molecular work without a clue on the 
morphology can make it look that way), but rather a question of how to 
decide which molecular and morphological data are most reliable as 
indicators of phylogeny in any given case.    

-- 
Dr. David Campbell
425 Scientific Collections Building
Department of Biological Sciences
Biodiversity and Systematics
University of Alabama, Box 870345
Tuscaloosa AL 35487-0345  USA





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