Guppies Evolve Their Spots in Experimentation

Guppies are popular freshwater aquarium fish. As with the pheasants we met in Chapter 3, the males are more brightly coloured than the females, and aquarists have bred them to become even brighter. Endler studied wild guppies (Poecilia reticulata) living in mountain streams in Trinidad, Tobago and Venezuela. He noticed that local populations were strikingly different from each other. In some populations the adult males were rainbow-coloured, almost as bright as those bred in aquarium tanks. H...

 If Humans Were Like Chimpanzees

If we were hairless chimpanzees, our society would still Dok fairly familiar in some ways. We would live in families, be very social, hierarchical, group-territorial, and aggressive toward other groups than those we belong to. In other words, we would be family-based, urban, class-conscious, nationalist, and belligerent, which we are. Adult males would spend more time trying to climb the political hierarchy than with their families. But when we turn to sex, things would begin to look very dif...