Darwin suggested that within any species of animal, minor variations exist - perhaps in size, color, shape, strength, or some other minor trait. In the struggle to find food and escape from predators, such traits might give that animal an advantage, making it more likely to survive. If the animal can pass on that trait to its offspring, they too will have this survival advantage. Darwin's finches provide a good example. If a bird has a beak that helps it obtain food, it has a better chance of survival, so in time, only finches with long beaks remained where the cactus grew. But where only seeds could be found for food, the strong, wide- beaked finches thrived. Darwin called this natural selection. Others called it survival of the fittest. It simply means that organisms that best adapt to a changing environment survive, while those that don't lose out, and eventually die off. Which of the following is an example of natural selection?
