kinman2 at YAHOO.COM
Fri Mar 26 22:31:29 CST 2004
John Grehan wrote:
The preponderance of the morphological evidence is that the orangutan-human similarities are synapomorphies as they are uniquely shared features and there are far more of these for humans and orangutans than any other human-ape combination.
If one views gene sequence similarity as the basis of phylogeny then of course the morphology does not count. The morphological evidence conflicts with most (but not all) molecular sequence studies....
Molecular evidence is not confined to sequence similarity---there is also the "morphology of genes" (gene order) which can be extremely important, especially when that order is very improbable and thus relatively resistance to arguments about homoplasy. Also, my experience is that some genes are a lot more informative than others----an angiosperm phylogeny based on maturase genes seems a whole lot more reliable than certain other genes (which may have resulted in some of the overlumping of angiosperm ordinal taxa by APG). Of course, whole genomes will be even better.
If humans and orangutans form a true clade, there should be at least some evidence on the molecular side. If there isn't any, then I have no choice but to remain skeptical. I also do not like to play number games with synapomorphies. Many of your characters could be combined with others (being clearly non-independent of one another). I had many arguments (a few years back) with a dinosaur cladist on the Dinosaur Mailing List where he would claim to have more synapomorphies than I did, so his hypothesis was therefore "better". What a bunch of poppycock. I see that recently he was having trouble keeping one of his favorite "clades" from splitting up. My arguments that it was paraphyletic had been rejected just because I had fewer synapomorphies than he did. I was delighted to recently read that (partially in jest) he even expressed his frustration by exclaiming "damn the ghost of Ken Kinman". I also expect to be "haunting" the overconfidence of other strict cladists in years to come, and some eclecticists as well (both sides have their problems).
I would admittedly be delighted if an orangutan-human clade existed, but inflating the number of synapomorphies and casually dismissing molecular evidence is not going to convince me that your hypothesis is correct. Which genus of the traditional (paraphyletic) Pongidae (sensu lato) is sister group to Family Hominidae is still an open question in my mind. Those who prefer a Pan-hominid clade need morphological evidence to substantiate their claim, and those who prefer a Pongo-hominid clade need molecular evidence to substantiate theirs. Until then, I am sitting on the fence and even considering the alternative phylogeny I mentionned earlier (hominids as sister group to a Pan-Gorilla clade). I certainly never said "morphology does not count", but one can be mislead by morphological evidence just as easily as one can be mislead by molecular evidence.
-------- Ken Kinman
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