Wills' enthusiasm gushes as he describes the period gene/speciation story as " the most vivid example of genetic wisdom". Then, without pausing for breath, Wills juxtaposes this and other examples of dramatic phenotypic alterations that are caused in Drosophila by simple genetic changes with examples in human phenotypic evolution that people have historically thought of as major changes and asks, might recent evolutionary changes in human skull shape, jaw shape, and brain development also be due to a few simple gene changes?
The stage is thus set for Part IV, The Brain. Wills gets down to brass
tacks in Chapter 11 where he asks if a few genetic changes in the human
lineage have modified our brains to make them larger and to allow us to
concentrate on our larger (a larger mental world than other animals, because
of the larger brain) inner mental world for longer periods of time and
also allow us to learn huge amounts from interactions with other members
of our social group. In Chapter 12 Wills gets to the important issue of
human language: identifying the brain mechanisms that make human language
possible is important, and Wills predicts that there may be just a few
critical genetic modifications of the primate brain that make it possible.
In the end, Wills is reduced to a fairly simple conclusion: the recent
rapid appearance of features (like language centers) in man's unique brain
and our complex social world in which cultural knowledge is passed from
brain to brain have evolved together in what he refers to as a "runaway
process" (presumably something like the Baldwin (Wills does not use the
term, See Dennett's book, DDI,
for coverage) effect is at work). And, gee, it would be nice to know the
details!
Go to John's
Home Page.