On his visit to the Galapagos Islands, Charles Darwin discovered several species of finches that varied from island to island, w
hich helped him to develop his theory of natural selection. It is believed that all of these species had one common ancestor and, over
time, evolved into different species. After the burst of speciation in the Galapagos, a total of 14 species would exist: three species
of ground-dwelling seed-eaters; three others living on cactustes and eating seeds; one living in trees and eating seeds; and 7
species of tree-dwelling insect-eaters. The finches varied mainly in the size and shape of their beaks. What characteristic of the
different islands most likely "selected" the most fit on each island?
Because food sources varied from island to island, the finches with the best beak size and shape for the available food survived and reproduced better that those with beaks less suited to that particular island. Over time, the finches evolved into separate species.