Thursday, March 29, 2007

Human Evolution Continues?

It has sort of been thought that evolution of modern humans had stopped when humans with modern characteristics first appeared. Now a geneticist, Gregory Cochran, and an anthropologist, John Hawks, state that evolution has been proceeding faster in the last ten thousand years than in the presumed "origin" of modern humans 160-200 thousand years ago. In an article in World Science, they state that modern human brain cases have continued to change dramatically. According to the article:

An­thro­po­l­o­gist Jef­frey Mc­Kee of Ohio State Uni­ver­si­ty said the new find­ings of ac­ce­l­er­ated evolution bear out pre­dic­tions he made in a 2000 book The Rid­dled Chain. Based on com­put­er mod­els, he ar­gued that ev­o­lu­tion should speed up as a pop­u­la­tion grows. This is be­cause pop­u­la­tion growth cre­ates more op­por­tu­ni­ties for new mu­ta­tions; al­so, the ex­pand­ed pop­u­la­tion oc­cu­pies new en­vi­ron­men­tal niches, which would drive ev­o­lu­tion in new di­rec­tions.

This is exciting, and may open doors for many different areas of research. It also puts a bit of a crimp in the "rapid replacement" model of modern humans origins. Put simply, if evolution has not slowed down with the advent of modern humans, then it is more of a continuum than was previously thought.

Hat tip to Glenn Reynolds.

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