HUMANITY'S DESCENT

How has the ebb and flow of the environment affected the evolution of humans, and how has the path of our evolution affected our attitude toward nature? Potts, of the Smithsonian Institution, offers some provocative ideas in a wide-ranging, recondite study. To understand ``how the kiln of evolution forged our apparent domination,'' he argues that we must pay more attention to the history of environmental change. This is not a recycled version of the old brand of environmental determinism, which argued that nature had crafted every facet of humanity. Instead, it is a theory attempting to frame humans within the context of an environment that is not static, in which the flux of nature elicits creative responses. He delves into the evolution of plants and animals, guided by the conditions these organisms face (climate, habitat, the impact of other species and our own) and seeking in such encounters the environmental genesis of human qualities. Everywhere he finds evidence of how environmental change repeatedly posed challenges to our ancestors, problems that were met with increasingly sophisticated responses: symbolic thought, creativity and imagination, complex social institutions, reciprocity and exchange. Potts can be numbingly rarified—tracking changes in sea level, monitoring population density and how it affects the arrangement of plants and animals—but he can also be lucid and animated, as when poking holes in current archaeological and anthroplogical theories assuming stable environments over the course of human evolution. He may well be on the right track, but as Potts admits, all of this begs the question of how to resolve our current environmental conundrums. Thus his fitting and ambiguous concluding note. We have to reengage with the natural world, he argues, and embrace the heady mix of our responsibilities: accepting the need to sometimes counter nature's flow in order to preserve our species, yet always be mindful of the long-term consequences. (Illustrations, maps, charts) (Author tour)