[Taxacom] Mona Lisa Smile
lammers at uwosh.edu
Tue Jul 25 17:00:41 CDT 2006
----- Original Message -----
From: John Grehan <jgrehan at sciencebuff.org>
> Mona Lisa smile: The morphological enigma of human and great ape evolution.
> The science of human evolution is confronted with the popular chimpanzeetheory and the earlier but largely ignored orangutan theory. The quality and scope of published documentation and verification of morphological features suggests there is very little in morphology to support a unique common ancestor for humans and chimpanzees. A close relationship betweenhumans and African apes is currently supported by only eight unproblematic characters. The orangutan relationship is supported by about 28 well supported characters, and it is also corroborated by the presence of orangutan-related features in early hominids. The uniquely shared morphology of humans and orangutans raises doubts about the almost universal belief that DNA sequence similarities necessarily demonstrate a closer evolutionary relationship between humans and
chimpanzees. A new evolutionary reconstruction is proposed for the soft tissue anatomy, physiology, and behavioral biology of the first hominidsthat includes concealed ovulation, male beard and mustache, prolonged mating, extended pair bonding, 'house' construction, mechanical 'genius', and artistic expression.<
I find myself wondering if part of the problem we have in discerning these two hypotheses is that we have locked ourselves into cladistic thinking to the point that it really colors our thinking. We are, after all, dealing with fairly recent low-level events. I have always maintained that such population-level phenomena may not be well represented by the perpetually dichotomizing model of cladistics. Instead of thinking of big dots (species) trailing lines behind them, which then fork at some point, we need to be thinking about populations -- enormous groups of individual dots living in their environment, doing whatever it takes to optimize survivorship and fecundity.
I don't doubt that the DNA data are "real" nor do I doubt that the morphological data are "real." Detailed discussions of parsimony, probability, bootstrap values, etc. are not what is needed to resolve the conundrum. An understanding of *biology* is what is needed. Unfortunately, in the last two decades, we have raised up too many biologists who don't know much about biology ...
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