Climbing Mount Improbable

While an enzyme molecule or an eye might seem supremely improbable in their complexity, they are not accidental, nor need we assume that they are the designed handiwork of a Creator, asserts Oxford biologist Dawkins (The Selfish Gene). This foremost neo-Darwinian exponent explains the dazzling array of living things as the result of natural selection--the slow, cumulative, one-step-at-a-time, non-random survival of chance variants. Both a frontal assault on creationism and an enthralling tour of the natural world, this beautifully illustrated study is based on a set of BBC lectures, imparting a tone at once conversational and magisterial. Dawkins explores how ordered complexity arose by discussing spiders' web-building techniques, the gradual evolution of elephant trunks and of wings (birds, he concludes, evolved from two-legged dinosaurs, not from tree gliders) and the symbiotic relationship between the 900 species of figs and their sole genetic companions, the miniature wasps that pollinate specific fig species. Using ""computer biomorphs"" (simulated creatures ""bred"" from a common ancestor), Dawkins demonstrates how varieties of the same plant or animal species can vary in shape because of differences in just a few genes. Author tour. (Sept.)