Abstract

Ian Tattersall is curator emeritus of the Spitzer Hall of Human Origins at the American Museum of Natural History, and an authoritative voice on the subject of human origins. The book offers anyone a chance to catch up on the current state of the art. One thing we learn is that the comparison with apes is misleading. None of our ancestors were much like an ape. Hominid forebears have been evolving rapidly and dramatically away from apes for more than two million years. Hunting is another red herring. We did not evolve to be hunters, or under conditions where hunting success was crucial to survival. Technology also does not drive our evolution. New stone technologies never emerge with new species. In each case, old kinds of hominids begin to do new things with stone and other material. What most differentiates early hominids from chimpanzees, and disqualifies emphasis on hunting, is that coming down from the trees to walk on two legs made hominids opportunistic generalists. As Tattersall tells it, the acquisition of modern human qualities was not a gradual, progressive accumulation of adaptations, nor is the emergence of our species predictable from earlier trends, or a threshold effect of gradually rising brain size. It was an abrupt and recent event, primarily in response to deteriorating (increasingly dry and cold) climate. We did not adapt genetically to the changed conditions, but accommodated to them through culture, creating a lifestyle with a new level of freedom from the environment, which might change without making people unable to cope. Maybe that is why many today remain indifferent to the threat of climate change. We are accustomed not to worry about such things. We have always pulled through. Such optimism is bred in the bone. But it was only right in the past, and this comfortable habit may be our doom.