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Darwin-L Message Log 7:70 (March 1994)

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.


<7:70>From SMD@utkvx.utk.edu  Sun Mar 20 12:40:38 1994

Date: Sun, 20 Mar 1994 13:40:28 -0500 (EST)
From: "Steven M. Donnelly" <SMD@utkvx.utk.edu>
Subject: hominid fossils in TIME and the origin of modern humans
To: darwin-l@ukanaix.cc.ukans.edu

I've been following the discussion on the TIME article, the new dates for the
Javan Homo erectus fossils and the origin of modern humans with a great deal of
interest.  I would like to make a few points........

1: I find it interesting that in discussing the origins of modern humans a
few people talked about mutations, e.g. someone wanted to know why the same
mutation couldn't have arisen independently in several populations.  What I
find so interesting about explaining modern human origins in terms of
mutation(s) is that it says a great deal about how highly we think of ourselves
in comparison to other animals.  We're apparently so different from the other
animals that we must be the product of some really major mutation.  I've read
journal articles in which it was claimed that modern humans are the result of
a macromutation that resulted in a drastically re-organized and much improved
brain, the poor stupid Neandertals, couldn't compete and so they went extinct.
Serves them right too, for not being as clever as we are.

Proponents of the multiregional theory do not believe that modern human origins
can be explained in terms of a mutation, or mutations, that arose in one
population and then spread.  They believe that the differences between modern
humans and the earlier forms of Homo sapiens are the result of new combinations
of genes and changes in the frequencies of genes that were already present in
earlier populations.

2: Proponents of multiregional evolution also do not believe that the
transition from archaic to early modern Homo sapiens occurred at the same time
in all areas of the world, or that it happened independently in several
regions.  Franz Weidenreich, the first advocate of the multiregional theory,
believed that regional Homo erectus populations, for example populations in
China and Java, were tied together by gene flow. Gene flow is still an integral
part of the mulitregional theory.

3: Earlier, someone (I forget who) stated that he knew of no other example of a
widespread species evolving into another species throughout its range.  I can
think of three examples offhand.  All of them involve rodents.  My favorite
example involves a Plio-Pleistocene lineage of voles which was spread
throughout Europe, from northern Spain to the Ural mountains,  Within this
lineage are four 'chronospecies'; the transitions from one species to another
occurred over most of the species' range (references available on request).

4: Someone else (again, I can't recall the name) stated that Asian Homo erectus
possess a number of distinctive features which are not found anywhere else.
This is often cited as evidence that they must be a different species.  In
fact, these 'uniquely Asian features' are found in Homo erectus fossils from
other areas of the world, and they're also present in some early Homo sapiens
fossils.  There are no autapomorphic features found only in east Asian Homo
erectus.

5: Finally, I don't doubt that the dates of 1.8 and 1.6 Myr obtained by
Swisher et al. for the volcanic pumice (I think it was pumice) are accurate.
What is questionable is the relationship between the fossils and the dated
pumice.  First of all, the fossils themselves may have been redeposited from
more recent deposits.  Secondly, Swisher et al. state that the deposits from
which the volcanic samples were taken are conglomerates. The pumice could be
much older than the deposits that it was taken from. This is the main reason
that I'm still skeptical about these dates.

     Steven Donnelly

     Department of Anthropology
     University of Tennessee-Knoxville
     BITNET:    smd@utkvx
     INTERNET:  smd@utkvx.utk.edu

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