Adaptation
A whale’s flipper, a monkey’s arm, and a horse’s foreleg all look very different. Yet these animals gave the same basic combination of bones in their forelimb, as do all other mammals. Each has adapted to its environment after millions of years of evolution from a common ancestor. With its long, thin bones, a bat’s forelimb is adapted for flying. With its short, strong bones, a mole’s forelimb is adapted for digging.