human origins

Richard.Zander at MOBOT.ORG Richard.Zander at MOBOT.ORG
Thu Jan 22 10:57:14 CST 2004


Well, hang on a minute there. The molecular data are commonly sufficient to
allow statistical tests of reliability but morphological data are generally
not. It isn't just "genetic sequence similarity" to the exclusion of
morphological data.

Naturally, the presumption is that if random generation of parallel traits
in closely related but not sister lineages is not to be expected by chance
alone, one can assume shared ancestry of apparent sister taxa. This is not
exactly true since coadaptive traits associated with habitat may also force
parallelism (pointed out by Landrum, Rensch and doubtless others) and thus
confound at least details of a cladogram. Both morphology and exons are
liable to this problem, I believe.

Statistcally impressive results from introns and junk DNA are hard to
explain away.



-----Original Message-----
From: Ronaldo [mailto:ralperin at TERRA.COM.BR]
Sent: Thursday, January 22, 2004 4:06 AM
To: TAXACOM at LISTSERV.NHM.KU.EDU
Subject: Re: [TAXACOM] human origins


Hello John,

Wednesday, January 21, 2004, 1:23:53 PM, you wrote:



"So in conclusion the paper is fairly representative of what I am reading
 in general. The chimpanzee relationship is presented as a fact. It is
 based on the presumption of genetic sequence similarity being the whole
 truth of phylogeny, and morphological considerations are rendered almost
 a foot note with the consequent lack of rigor in any connection being
 substantiated between living humans and other apes and purported fossil
 representatives. "


 Fully agreed! John, here in Brazil we have the same situation with
 the primates in general. Just see the huge number of papers regarding
 "Phylogenetic" relationships among Neotropical Primates. I have to
 ask; "Phylogenetic" or Molecular (with no explicit criteria)
 relationships?


 Ronaldo Alperin

JG> John Grehan

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http://www.sciencebuff.org/biogeography/Panbiogeography/Panbiogeography-Gate
.htm
JG> http://www.sciencebuff.org/HepialidaeGate.htm





--
Best regards,
 Ronaldo                            mailto:ralperin at terra.com.br




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