"Over the last three million years or so, our lineage has diverged sharply from those of our great ape relatives. Change has been rapid (in evolutionary terms) and pervasive. Morphology, life history, social life, sexual behavior, and foraging patterns have all shifted sharply away from those of the other great apes. No other great ape lineage--including those of chimpanzees and gorillas--seems to have undergone such a profound transformation. In...