The Runaway Brain: The Evolution of Human Uniqueness

Wills begins this superb, detailed, lucid survey of current controversies over human origins by debunking the popular theory that all human beings share a common ancestry rooted in a particular kind of DNA from a ``mitochondrial Eve'' who lived in Africa some 200,000 years ago. Next, he applies new findings from molecular genetics and fossil digs to clarify the two competing models of human evolution: the ``politically correct'' Noah's Ark model, which holds that modern humans arose relatively recently in Africa and fanned out through the Old World, replacing less advanced hominids; and the multiple-origins model, according to which our ancestors made the transition to full humanity more than once, in different parts of the planet. A biologist at UC San Diego, Wills suggests that Homo sapiens is caught up in a process of ``runaway brain evolution,'' the result of a feedback loop between genes and the environment, which has transformed our brains into ``sponges for knowledge,'' giving human evolution the appearance of progress and directionality. Illustrated. First serial to Discover; Library of Science main selection. (Aug.)