Humans and apes

[A.P. Jason de Koning]

John:
> I take it I am disingenuous or
> misleading in presenting the public with a scientific debate with
> information on how the different views are each supported.

No.  In my view, not if you represent each hypothesis fairly with respect to
the supporting and contradictory evidence.

John:
>The only major objection so far has been the molecular data

While I disagree with this, I think we can agree that if one throws out the
molecular evidence, there IS more uncertainty.  But why do this?  In the
field, molecular data gets high precedence on the question because it is
highly consistent on hominoid phylogeny, not for some automatic reason.
Your claim that molecular data is problematic 'if it is phenetic' is
puzzling to me.  Molecular data is often analysed 'cladistically' by maximum
parsimony.  Otherwise, the most commonly used probabilistic approach for
rigorous analysis (maximum likelihood), IS cladistic!  It chooses the
topology that is most likely to have given the observed character states,
considering all possible ancestral states "weighted" by their probability
(as specified by a model).  Maximum parsimony can be shown to be a special
case where transition rates are assumed equal, and branch lengths are
ignored (e.g., papers by Hendy).

> I guess I am lost at sea with this. If morphology is misleading and
> genetics is not, morphology remains uninformative about phylogeny.
Weighing
> misleading evidence seems problematic.

Perhaps we don't understand each other here.  Morphology and phenotypic data
CAN be misleading.  So can genotypic data.  But since phenotypic traits are
moulded more directly and (probably) frequently by natural selection, they
become more rapidly skewed away from the underlying historical signal.  That
doesn't mean that phylogenetic information is unrecoverable.  In any case,
we have no a priori way to identify misleading characters, except by
comparing them to other characters.  Hence, if different characters conflict
in their phylogenetic signal, we hope that by looking at more characters, we
can find the 'uncorrupted' historical signal by consensus.  Yes?

>Well I intend to be selective only in an informed way - i.e I am looking
>with great interest to the details of the Homo-African apes papers.

Since the hard-tissue evidence is a source of disagreement, have you
considered the soft-tissue data?  Gibbs, Collard, and Wood (2002; J. Anat
200: 3-49) analysed data on 171 soft tissues in the hominioids, and
performed resampling statistics to measure confidence.  Their result was:
Homo, Pan = 95%; Gorilla, Pan, Homo = 96%.  Interestingly on re-reading this
paper, they claimed that a statistical analysis of Shoshani's data indicates
that it does not produce a robust resolution (!)

Incidentally, would you kindly post the full references to the more recent
of Schwartz's papers that you've cited in this thread? There have been
claims in the literature that Schwartz himself has abandoned the human-orang
idea (e.g., Begun, 1999 in Parker, Mitchell, and Miles), though I haven't
seen hard corraboration of this.  If he is still promoting the idea, that
does indeed seem pretty unfair...

Best wishes, and good luck with your exhibit.
- Jason

__________________________________________________________________________
A.P. Jason de Koning, Doctoral student       Email: apjdk at albany.edu
  Department of Biological Sciences            Lab: (518) 442-4347
  University at Albany, SUNY                   FAX: (518) 442-4767
  1400 Washington Ave., Albany NY 12222, USA Mobil: (518) 210-4504
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