Darwin's Other Great Theory: Sexual Selection, or Why Men are from Mars and Women are from Venus?

Summary: Darwin's is best known for his theory of natural selection which explains how organisms evolve adaptations for survival. His second theory, sexual selection, attempts to describe why males and females of the same species can differ so markedly, and why the sexes can have traits that decrease their ability to survive. Dr. Michael Ryan, Smithsonian Tropical Research Institute and zoology professor at the University of Texas, Austin, reviews our understanding of sexual behavior in animals, including humans.