[Taxacom] Robust argument
jgrehan at sciencebuff.org
Sun Jun 28 09:08:51 CDT 2009
> From: mivie at montana.edu [mailto:mivie at montana.edu]
> Sent: Sunday, June 28, 2009 9:48 AM
> To: John Grehan
> [stepping back, taking a breath and putting on my serious hat]
> I do not understand the idea that the Homo-Pongo hypothesis is
> ignored? Indeed when specifically and clearly stated phenetic
> genomic data are used, the Homo-Pan similarity is always highlighted,
> note I said "similarity" which I think we dealt with about 1982 as not
> being the same as "relationship." In that context such things as
> 98% of their genome" and "humans' closest relative" does not mean
> phylogenetic relationship but similarity.
The Homo-Pongo hypothesis is routinely ignored by molecular analyses
because the morphological evidence is never discussed and the
possibility that it might represent a potential falsifier of molecular
similarity is never addressed.
I agree with the similarity statement not being the same as phylogenetic
relationship, but unfortunately the two are usually conflated.
> I routinely see the phylogenetic relationship stated to be confused
> still being debated when referenced in the scientific literature and
> discussions. Thus, the Pongo+Homo hypothesis is not ignored as you so
> often claim.
I am willing to be corrected. Where in the literature is there
discussion and evaluation of the morphologically based orangutan theory
> I think that the only place you fall down in this discussion is an
> apparent do-or-die search for anything that you can raise to support a
> previously decided upon truth (Pongo-Homo are sisters). The
> question of what is the living sister of Homo is much more open in the
> literature, although really not that interesting to most
> researchers who concentrate on the fossil search for a sister-group,
> rely 100% on morphology.
I started out having no opinion about human origins and the great apes
until Alan Walker referred to it as the "lunatic fringe". When I learned
of Schwartz's theory I looked at this evidence. He seemed to provide a
coherent cladistic argument. When I asked various authorities supporting
the chimpanzee relationship and asked what was wrong with his evidence
or how was his evidence falsified, I was unable to get anything of
substance - just quite a lot of hostility or nothing at all (I had the
unpleasant experience of one proponent yelling at me and my wife across
a table). There were a few exceptions among morphologists, although they
usually just appealed to molecular similarity as the disproof of the
orangutan evidence. So I decided to investigate for myself, looking into
the molecular argument as well as the morphological evidence provided by
Schwartz and chimpanzee supporters. I found Schwartz's evidence to be
more verifiable than the chimpanzee evidence in morphology, and I found
quite a few reasons for why the molecular evidence may not always give
the right answer. I have published on my work in respected scientific
journals. So now I keep challenging anyone and everyone on the evidence.
If I fall down in prosecuting this matter than I am no worse than anyone
else who has done the same - whether Darwin or Croizat.
Those who study fossils for the "sistergroup" do not do so without
considering the living taxa. If the sistergroup of 'Homo" (whatever that
is - and that remains a problematic taxon)is represented by one or more
australopiths, the question of their relationship to the great apes can
only be investigated through morphology (as you point out) and what is
interesting is that there are more synapomorphies shared between
Homo/australopiths and orangutans than with chimpanzees, and that
australopiths also share several apomorphies with orangutans/fossil
orangutan relatives (that would have to be regarded as plesiomorphies
within the Homo/australopith clade).
Still looking forward to the scientific rebuttal of panbiogeography.
> > Bob,
> > I don't think there should be any trepidation over expressing any
> > of view on TAXACOM. I inserted some comments below which Bob also
> > at the end. I agree with the questions Bob has raised about the
> > assumptions and interrelationships of evidence.
> > I believe these issues over morphology and molecules have largely
> > away in the closet when it comes to the assertion of molecular
> > the be all and end all of evolutionary relationships. One sees this
> > the way the orangutan sistergroup theory has been dismissed as
> > "preposterous nonsense" and "loopy"(behind a veil of anonymity of
> > course)even though the relationship is based on a fairly standard
> > cladistic analysis and for the most part very well documented and
> > corroborated apomorphies. Of course someone could come along and
> > demonstrate either that these apomorphies for the most part do not
> > exist, that our data was wrong, or that they will demonstrate that
> > humans and chimpanzees do indeed (and despite the failure to show
> > so far) share far more apomorphic features than humans and
> > But as long as the orangutan evidence gets ignored there will be no
> > resolution either way.
> > Its been interesting for me, a relative bystander at the beginning,
> > see how often ignoring the orangutan theory was justified by
> > ignoring the theory. Perhaps this is another principle of science
> > should be taught to students: Grehan's first theorem of science -
> > Ignoring a theory is justified by everyone ignoring it.
> > Sorry, I apparently lack a sense of humour.
> > John Grehan
> >> bounces at mailman.nhm.ku.edu] On Behalf Of Bob Mesibov
> >> (1) Because the genome is passed on from generation to generation,
> >> contains information we need to infer evolutionary history.
> > Perhaps so, but what is the 'information'? A widespread assumption
> > that sequence counting of one form or another represents that
> > 'information'. Others have pointed out that the genome is not the
> > thing passed on from generation to generation.
> >> (2) It is possible to infer evolutionary history using information
> > the
> >> genome.
> > How do we know that? And again in what form does that information
> >> (3) Morphology also contains information of use for inferring
> > evolutionary
> >> history.
> > But is morphology separate from the genome?
> >> (4) It is possible to infer evolutionary history using information
> > from
> >> morphology.
> > If (3) is true
> >> (5) Literally speaking, morphology is not inherited, so
> >> information is second-hand data derived from a heritable source:
> >> genome.
> > Not by itself perhaps, but if morphology is consistently
> > generation to generation then the process is inherited and there is
> > nothing 'second hand' about it. It would seem to be just as much a
> > of the genome as the DNA molecules.
> >> (6) No other kind of information can be used to infer evolutionary
> >> history, because no other information is inherited.
> > Geography as some have mentioned. And geographic information has
> > occasionally been used to predict phylogeny.
> >> (4) has been the basis for evolutionary inference for a long time,
> > for
> >> a shorter time. Many people believe that (2) is better than (4)
> > because of
> >> (5), and because there is more (1) information than (3)
> >> The logic here needs defending. Why should (5) make (4) any less
> > reliable
> >> than (2)? (I think this is one of Richard Zander's points.) How do
> >> compare the reliability or resolution of (2) vs (4), given that we
> > have no
> >> time machine and no other information (see (6)) that can
> > be
> >> used to infer past events? How do you know that there is more
> > independent
> >> information from (1) of use for historical inference than from (3)?
> >> I think these 3 questions go to methodological assumptions. Should
> > these
> >> assumptions be taken as givens, equally reliable from group to
> > It
> >> worries me that posters have written THEORETICALLY in caps without
> >> spelling out their thinking.
> >> I also point to (6), which is nonsense, and comes from thinking
> >> organisms divorced from their geographical location and their
> > ecological
> >> associations (think of parasitism, insect/host plant interactions,
> > etc).
> >> (6) should not be confused with (7), which might read "It is
> > to
> >> infer evolutionary history from biogeography and ecological
> > associations."
> >> That history might be blurrier than (2) and (4) histories, but how
> >> total evidence enthusiasts justify their insistence on using (1)
> > (3)
> >> evidence to the exclusion of (6) evidence? (Or is it just that
> >> evolutionary historians can't be bothered studying all the
> > phenomenally
> >> complicated, ungeneralisable facts of what used to be called
> >> history?)
> >> --
> >> Dr Robert Mesibov
> >> Honorary Research Associate
> >> Queen Victoria Museum and Art Gallery, and
> >> School of Zoology, University of Tasmania
> >> Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
> >> (03) 64371195; 61 3 64371195
> >> Website: http://www.qvmag.tas.gov.au/mesibov.html
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