[Taxacom] orangutans and metaphysical claims

John Grehan jgrehan at sciencebuff.org
Sun Jun 28 09:18:27 CDT 2009


I sometimes wonder if anything in science is not metaphysical in some
sense. I continually see new fossils trumpeted as the 'ancestor'. How
much more metaphysical can one get? And to top it off there is the case,
all to frequent in hominid studies, where one cannot get open access to
holotypes which precludes independent verification of theoretical claims
and therefore effectively renders those fossils metaphysical entities.

 

Perhaps the orangutan knows - after all, it is called the Philosopher
Ape.

 

John Grehan

 

 

________________________________

From: Richard Zander [mailto:Richard.Zander at mobot.org] 
Sent: Thursday, June 25, 2009 7:27 PM
To: Richard Pyle; John Grehan; taxacom at mailman.nhm.ku.edu
Subject: RE: [Taxacom] orangutan outrage

 

Rich Pyle's comments are cogent but I'd like to add another dimension.

 

Macroevolution is the transition from a node on the cladogram to a taxon
represented by an exemplar. "Phylogenetically informative" only refers
to information about sister-group relationships, not about
macroevolution. 

 

Both creationists and phylogeneticists abhor macroevolution:  one says
new species are derirved from a metaphysical god, the other says they
are derived from a metaphysical node (representing an unnamed shared
ancestor). Descent with modification is not directly represented in
phylogenetic data sets, which are analyzed for their sister-group
information. 

 

I'll bet molecular information will be really informative about
ancestor-descendant (macroevolution) relationships, but it is not
apparent in most published phylogenetic studies. (If morphological
traits can be mapped on a molecular tree, why not taxa?) The
relationships of homo, pan, gorilla, and pongo with their nodes, seems
critical. Can we characterize the nodes?

 

If gorilla and pan were on a very short shared branch that did not show
up in molecular cladograms, then the paraphyletic group homo-pongo would
be the ancestor of gorilla-pan (mapping the traits that characterize the
taxa). Any evidence for a short molecular branch connecting gorilla and
pan?

 

_______________________

Richard H. Zander

Missouri Botanical Garden

PO Box 299

St. Louis, MO 63166 U.S.A.

richard.zander at mobot.org

 

 

________________________________

From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Richard Pyle
Sent: Thu 6/25/2009 1:30 PM
To: 'John Grehan'; taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] orangutan outrage

 

John:

Is it your contention that there is phylogenetically informative
information
contained within morphology that is not *somewhere* in the genome?

Or, is it merely your contention that we are not yet able to extract the
phylogenetically informative information from the genome yet, and
therefore
morphology serves as a more reliable indicator in many/most
circumstances?

I could be persuaded about the latter, but the former is a very tough
sell.
If there is phylogenetically informative aspects of morphology that are
not
*somewhere* in the genome (independent of our current ability to
decipher
it), then I'm struggling to understand how that information can exist
(i.e.,
if it's phylogenetically informative, then it really must be heritable).

Don't get me wrong -- I'm certainly in the camp who believe that
molecular
data are often over-rated, and lead to a false sense of confidence in
results.  However, I see this not as a failure of the *concept* (i.e.,
that
the genome is rich with information useful for reconstructing
phylogeneies),
but rather as a failure in our ability to put molecular data in its
proper
context, given our current state of understanding for how to interpret
it
properly.  I am confident that we will eventually (perhaps within my
lifetime) have the necessary understanding to fully extract the
phylogenetically valuable information from the Genome, at which point
morphology will be useful primarily for bridging extant organisms to
fossil
organisms.

I'm also keeping an open mind to the possibilities that:
1) There may be phylogenetically useful information observable in
morphology
that does not exist somewhere in the genome (though I'm struggling with
imagining a mechanism);

2) It may not be possible (ever) to extract all of the phylogenetically
useful information from the genome (hard to fathom, given that the
phylogenetically informitive morphology is almost by definition derived
from
the genome, and if the biomolecules know how to extract that
information,
then we should eventually be able to do so as well);

3) Human civilization may collapse before we achieve the necessary level
of
understanding of the phylogenetic aspects of genomic information.

Aloha,
Rich




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