[Taxacom] Evolution of human-ape relationships remains open forinvestigation

[Richard Zander]

Well, I still think the man-ape controversy is a fine test of reasoning,
and I don't think we can or should burn out over it.

My continued explanation is that one or the other is not wrong because
neither is exclusive of the other. Molecular cladograms track genetic
continuity and isolation events. Morphological cladograms are a kind of
natural key. You can put them together with an overarching theory of
macroevolution.

For example, two macroevolutionary theories jump forth as plausible:
organs and humans originated from a similar common ancestor and gorillas
and chimps evolved at different times from that ancestor. Second is that
the gorilla and chimp evolved from a similar ancestor that came out of
an orang-type ancestor and humans are throwbacks to that morphotype.
Either theory supports both molecular and morphological analyses,
assuming the analyses are correct.

Rather than proving the other side wrong, why not come up with data that
support a macroevolutionary scenario that allows both to be right?

 

* * * * * * * * * * * *
Richard H. Zander
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA  
Web sites: http://www.mobot.org/plantscience/resbot/ and
http://www.mobot.org/plantscience/bfna/bfnamenu.htm
Modern Evolutionary Systematics Web site:
http://www.mobot.org/plantscience/resbot/21EvSy.htm

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
Sent: Thursday, August 04, 2011 9:54 PM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Evolution of human-ape relationships remains open
forinvestigation

Interesting:
      The last sentence in the abstract refers to "the fact that
identification of shared similarity does not translate into
demonstration of synapomorphy."                  
       Ironically, that has actually been my biggest criticism of the
theory that orangutans and hominids form an exclusive clade---that the
identification of shared similarities between orangutans and hominids
does not translate into a demonstration of synapomorphies (but that they
are actually most likely symplesiomorphies).   
       So I think both sides of this debate are probably wrong.
Hominids probably didn't clade exclusively with either orangutans or
with chimpanzees, but instead clade as sister group to an exclusive
chimp-gorilla clade.       
      This would mean that hominid characters shared with orangutans are
symplesiomorphies of the great apes, and hominid characters shared with
chimps are symplesiomorphies of the African great apes, and most
importantly that characters shared by chimps and gorillas are most
likely synapomorphies (and that there are no doubt a large number of
additional chimp-gorilla synapomorphies to be found if so many people
weren't hell bent on proving those other two supposed clades).       
      So I certainly agree with the subject line that the "Evolution of
human-ape relationships remains open", although a third theory (that
chimps and gorillas form an exclusive clade) is sadly not getting the
attention that it probably deserves.  Meanwhile, those championing
exclusive chimp-hominid or orangutan-hominid clades are probably BOTH
labelling symplesiomorphies as synapomorphies.  So I don't sympathesize
with either side of that debate, and that both are probably throwing
rocks from glass houses.   
               -------Ken Kinman