Darwin-L Message Log 2:92 (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.

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<2:92>From LANGDON@GANDLF.UINDY.EDU  Mon Oct 18 11:04:37 1993

Date: Mon, 18 Oct 1993 11:04:37 -0500
From: "JOHN LANGDON"  <LANGDON@GANDLF.UINDY.EDU>
To: darwin-l@ukanaix.cc.ukans.edu
Subject: Re: waterbabes

In message <9310160106.AA11055@ucmp1.Berkeley.EDU>  writes:
> I have been following (with about one eye) the aquatic ape thread on
> sci.bio on Usenet.  Most of the posts are devoted to yarn-spinning and
> just-so stories pro and con.  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?
>
> Unless, of course, we are willing to admit massive and homoplastic
> reversals in both the gorilla and (chimp,bonobo) clades ...

I am not a defender of the aquatic hypothesis. However, the only sense I can
make out of this question is that you misread the graph. Diamond shows the
human/Pan split at about 7 Myr. (The 1.7-2.0 figure is the % DNA difference.)
There is still enough uncertainty in this date that the strict chronology does
not rule out an extremely (phenomonally) rapid aquatic adaptation, but one that
effectively discards Australopithecus. However, the aquatic ape model (proposed
1960, developed 1972) makes the most sense under the 1970's and earlier
chronology where humans and chimps split 14 Myr. That time scale has since been
discarded.

JOHN H. LANGDON      email LANGDON@GANDLF.UINDY.EDU
DEPARTMENT OF BIOLOGY    FAX  (317) 788-3569
UNIVERSITY OF INDIANAPOLIS   PHONE (317) 788-3447
INDIANAPOLIS, IN 46227

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