Darwin observed 13 different species of finches and their different beak strutures. He observed their ability to consume foods such as nuts, bugs, and fruit. He concluded all were related to their beaks. For example, long slender beaks are good to reach in the flowers of a cactus. Darwin concluded that finches beaks are examples of adaptive radiation. To fit in the island, they had to adapt to the conditions. This lead Darwin's theory of natural selection.
