He served as a naturalist aboard the H.M.S.Beagle on a British science expedition around the world. In South America Darwin found fossils of extinct animals that were similar to modern species. On the Galapagos Islands in the Pacific Ocean he noticed many variations amoung plants and animals of the same general type as those in South America. He traveled from island to island he noticed that groups of birds on certain islands had evolved specialized beaks for collecting food. He observed that an entire species of the birds fed on one particular food source. However, as the food source became less abundant, groups of finches turned to alternative food sources on each island. Some birds developed short heavy beaks suited to breaking open the husks of seeds. Others developed long thin beaks that were adapted to picking food from bark or crevices in rocks. With specialized beaks, the birds were able to survive in different ecological niches. As they bred with other birds in their niche, they evolved into a completely different species, no longer able to interbreed with other finches. The interesting part of this phenomenon is that all the finches had been subjected to the same living conditions climate, food source, structure, etc.The principals of adaptation is perfectly proven in life?. (Charles Darwin).
Upon his return to London Darwin conducted thorough research of his notes and specimens. Out of this study grew several related theories: one, evolution did occur; two, evolutionary change was gradual, requiring thousands to millions of years; three, the primary mechanism for evolution was a process called natural selection; and four, the millions of species alive today arose from a single original life form though a branching process called specialization.? As many more individuals are produced than can possibly survive, there must be in every case, a struggle for existence, and either one individual with another of the same species, or with individuals of distinct species, pr with physical conditions of life.
