Problem : On his voyage with the Beagle, Charles Darwin carefully studied several species of finches. He found that many had come from a single species, but they had adapted to their environment by choosing different food sources and developing radically different beak designs to match their choice of food. What pattern of evolution did the finches show?

Problem : Many species of owls hunt only at night. These winged predators have evolved extremely sensitive hearing to help track insects and other prey. Another night hunting winged predator, the bat also has extremely sensitive hearing to track prey in the dark. What pattern of evolution does this show?

Problem : Imagine two types of ancient forest animals: a goat-like grazing animal and a small ground-dwelling rodent that lives on insect prey. At the same time, these two animals leave the forest and begin living in grassy plains. The rodent evolves large powerful claws for digging burrows to hide in, while the grazer develops long legs for running from predators. What type of evolution does this show?

Problem : What difficulty does convergent evolution pose for evolutionary biologists?