[Taxacom] Morphological molecular reconciliation again (was erecting or sinking higher taxa

Curtis Clark lists at curtisclark.org
Sun Oct 14 13:45:43 CDT 2012


On 2012-10-14 9:25 AM, John Grehan wrote:
> Richard's conclusion is only possible by saying that the morpogenetic
> evidence is wrong (i.e. throwing it out). And I did mention in my response
> an explanation for the molecular evidence being wrong in this case - that
> the molecular evidence result has been negatively affected by the presence
> of unrecognized plesiomorphies (due to the phenetic nature of character
> state determination and analysis).

If I'm understanding Richard, he's hypothesizing that orangutans are a 
grade, that was at one time widespread, and that gave rise to chimps, 
bonobos, mountain and lowland gorillas, and humans, without itself being 
transformed by anagenesis. Those orangs that gave rise to humans had 
previously given rise to chimps, and so there would be expected to be 
strong molecular similarities between humans, chimps, and the extinct 
orang subgroup that gave rsie to them. But those orangs still share 
morphological features with the SE Asian orangs, and those features were 
less changed when humans speciated than when chimps, bonobos, or 
gorillas speciated. So the orang-human morphological similarities can 
appear to be symplesiomorphies relative to chimps, bonobos, and 
gorillas, while at the same time being evidence of close relationship.

Richard, am I on the right track?

-- 
Curtis Clark        http://www.csupomona.edu/~jcclark
Biological Sciences                   +1 909 869 4140
Cal Poly Pomona, Pomona CA 91768





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