Darwin's finches are an example of adaptive radiation, the evolution of an animal or plant group into different types adapted to specialized ways of life. Their common ancestor arrived on the Galapagos about two million years ago. Over time, Darwin's finches have evolved into 15 recognized species different in body size, beak shape, song and feeding behavior. The picture here shows finches with four different types of beaks. What statement best represents how one species of finches became many?