Darwin-L Message Log 2:95 (October 1993)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

Note: Additional publications on evolution and the historical sciences by the Darwin-L list owner are available on SSRN.

<2:95>From anemone@uno.cc.geneseo.edu  Mon Oct 18 12:09:26 1993

Date: Mon, 18 Oct 1993 13:12 EST
From: anemone@uno.cc.geneseo.edu (Robert L. Anemone)
Subject: RE:  waterbabes & hominoid cladistics
To: darwin-l@ukanaix.cc.ukans.edu

Barry Roth recently posted this (edited) message and query:

I do wonder how proponents of the aquatic ape scenario would respond to
the following:

>According to the DNA clock (and the figure on about p. 20 of _The Third
>Chimpanzee_ by Jared Diamond), the split between the gorilla clade and
>the clade (Homo,(chimpanzee,bonobo)) is set at about 1.7-2.0 Ma.  So how
>could climatic events in the late Miocene (ca. 7-5 Ma) have anything to
>do with autapomorphies of Homo?

I'm certain that I'm not the only Biological Anthropologist who noticed the
obvious mistake in the date for the split between gorilla and human-chimp
clades purported to come from Diamond's work. A quick look at the text of
"The Third Chimpanzee" revealed the mistake to be Roth's, not Diamond's.
The phylogenetic tree presented by Diamond as his Figure 1 (p. 21) has two
different Y axes. The Y axis on the right side of the tree has units of
millions of years ago (mya) while that on the left has units of percentage
difference in DNA (%DNA). Roth mistakenly read the figure of "about 1.7-2.0
Ma" off the left axis (%DNA). The phylogenetic tree actually suggests that
the percentage difference in DNA between gorilla and human-chimp clades is
on the order of 2%, and that the time of divergence of these two clades was
on the order of 10 mya.

In his Figure legend, Diamond states:
"...the common and pygmy chimps differ in about 0.7 percent of their DNA
and diverged around three million years ago; we differ in 1.6 pecent of our
DNA from either chimp and diverged from their common ancestor around seven
million years ago; and gorillas differ in about 2.3 percent of their DNA
from us or chimps and diverged from the common ancestor leading to us and
the two chimps around ten million years ago."

Please don't misconstrue my intent as providing some support for the
"Aquatic Ape" Hypothesis. However, the split between humans and some great
apes may very well have occurred during the Late Miocene.

Bob Anemone
Department of Anthropology
SUNY at Geneseo

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