[Taxacom] hominid evidence

Valeria Tavares tavares at amnh.org
Tue Jun 30 09:40:01 CDT 2009


Dear colleagues,
I have been following all the excitement of the discussion, panbio, DNA x
morphology...
Thanks for sharing such great "brownian" movement to our thoughts!
I read the article posted by John Grehan and particularly like the
quotation ..:
"They criticize molecular data where criticism is due," said Ebach, who
was not involved in the new study. "Palaeoanthropology is based solely on
morphology, and there is no scientific justification to favor DNA over
morphological data. Yet the human-chimp relationship, generated by
molecular data, has been accepted without any scrutiny."
To me very simplistically -- I know -- it makes me wonder how can this
discussion last so long in the literature and academic environments as it
seems obvious that both morphological characters and DNA bases are...
characters. Each being one "evidence" as such. Perhaps if I am sure that
"complex of genes b" is the sole and absolute comander of "complex of
morphological structure c" then I wouldn't bother to do both. I
particularly would have much more fun looking at the morphological
traits...Besides being cheaper and more "democratic" - no need to have a
super structure as sequencer, lab, etc... Indeed much of the base
constructed up to now to our evolutionary knowledge only needed a curious
and trained eye - and lots of observation and comparative anatomy.
Sorry if this was to silly for the discussion levels of this list,
Cheers (from an enthusiastic combined-evidence fan)
Valéria


> The great thing about publicity is that it can force people to respond
> when they otherwise whould not have to. The MSNBC article shows that at
>
>
>
> http://www.msnbc.msn.com/id/31624027/ns/technology_and_science
>
>
>
> Some quotes and comments
>
>
>
> "The DNA evidence <http://www.livescience.com/dna/>  is so strongly
> against it," said Frans de Waal, director of the Living Links Center at
> the Yerkes National Primate Research Center of Emory University in
> Atlanta. "It's a leftover from the days that bones ruled, but they don't
> anymore."
>
> This is the classic argument that the DNA evidence is so self-evident
> that it does not even have to be justified, not even in terms of
> systematics principles.
>
> "Many experts trust the genetic data because they say the physical
> similarities can be subjective. It's hard to tell whether two species
> independently evolved similar features, or actually descended from a
> common ancestor with those features."
>
> This is another rhetorical claim, and yet if the hominid paper shows
> anything it is that it is not all that hard at all to distinguish those
> character states that are independent and those that are descended from
> a common ancestor.
>
> "Many of these characteristics, we have no clue if they're literally the
> same traits in evolutionary terms," said Todd Disotell,
>
> This from a researcher who analyzes fossil relationships using
> morphology! Seems hypocritical.
>
> "The DNA data is more concrete, he said. The sequences of molecules
> composing genes can either be the same or different."
>
> Of course this begs the question of whether the sequences of molecules
> can always accurately reconstruct evolutionary relationships.
>
> We're truly talking [comparing] apples and apples, and oranges and
> oranges," Disotell told LiveScience. "This anti-molecular stance is just
> mind-boggling."
>
> Here is the intimation that some things in science are just not to be
> questioned.
>
>
>
> "Jeffrey has been claiming this for many years now in the face of
> increasingly insurmountable evidence to the contrary," said David Smith,
> an anthropologist at the University of California, Davis. "My own
> expertise is molecular, and I can assure you that there is not a shred
> of genetic evidence in support of his argument."
>
> Of course he conveniently missed the counterpoint - that there is almost
> not a shred of morphological evidence in support of the molecular
> argument.
>
> In other words, if the DNA evidence that many biologists use as evidence
> turned out not to accurately reveal evolutionary relationships, the work
> of many molecular biologists would be suspect.
>
> Indeed - and why not. If its ok for morphological work to be suspect,
> why not molecular?
>
> "If this was true, we would lose entire departments at major
> universities," Disotell said. "I would have nothing to do. I would go
> become a carpenter."
>
> The converse could be said of morphology. In fact in some ways this is
> what has happened to morphology.
>
> John Grehan
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Dr. John R. Grehan
>
> Director of Science
>
> Buffalo Museum of Science1020 Humboldt Parkway
>
> Buffalo, NY 14211-1193
>
> email: jgrehan at sciencebuff.org
>
> Phone: (716) 896-5200 ext 372
>
>
>
> Panbiogeography
>
> http://www.sciencebuff.org/research/current-research-activities/john-gre
> han/evolutionary-biography
> <http://www.sciencebuff.org/biogeography_and_evolutionary_biology.php>
>
> Ghost moth research
>
> http://www.sciencebuff.org/research/current-research-activities/john-gre
> han/ghost-moths
> <http://www.sciencebuff.org/systematics_and_evolution_of_hepialdiae.php>
>
>
> Human evolution and the great apes
>
> http://www.sciencebuff.org/research/current-research-activities/john-gre
> han/human-origins
>
>
>
>
>
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>
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“Para ser grande, sê inteiro: nada teu exagera ou exclui".
Sê todo em cada coisa. Põe quanto és no mínimo que fazes. Assim em cada
lago a lua toda brilha, porque alta vive” (Fernando Pessoa)
^v^______________________^v^
         Valeria C. Tavares, Ph. D.
         tavares at amnh.org
         val.c.tavares at gmail.com
         55 31 32960115
         55 31 87623454
^v^______________________^v^





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