mosaic evolution

Alex Duncan (
27 Nov 1995 23:12:21 GMT

In article <> H. M. Hubey, writes:

>>humans from ape-like hominoids is another. In fact, the fossil record
>>speaks to us very clearly about this issue in regard to hominid
>>evolution, and what it says is that hominids evolved in mosaic fashion,
>>through the gradual accumulation of human-like traits.
>All the traits slowly evolving simultaneously as in the
>way differential or difference equations model them
>or one at a time serially?
Unfortunately, I don't know how differential equations would model such
changes. Perhaps you could provide a short explanation?

Some human traits appear to have evolved together (e.g. reduction in size
of postcanine dentition & increase in brain size) while others don't
appear tightly connected -- it looks as if the anatomy associated with
bipedalism may have evolved in at least two (probably more) punctuated
evolutionary events.

>>In other words, using the fossil record as our guide, there is no reason
>>to assume that all human-like features appeared at once, and in fact
>Did she say all at once?

Yes, she basically said "all at once":

EM>>There is no evidence that they didn't happen at the same time and for
EM>>same reason, which would be far more parsimonious.

>So were all the traits simultaneously and slowly evolving
>or did they occur serially one after another?
See above.
>>there are very good reasons to assume otherwise. Your insistence on a
>>"one-size-fits-all" hypothesis is ridiculuous in light of what we know
>>about the way evolution happens.
>One-size-fits-all or one cause and one life-style that gives
>a good reason to assume all the changes were slowly occurring

You can look at this way if you want, but it's clearly not the way human
evolution happened.

>Are you claiming that they occurred serially or together?

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086