Any discussion of an organism's role in an ecosystem must center on evolution. Voyage of the Beagle Map
Charles Darwin, at age 50
I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection.- Charles Darwin, The Origin of Species
Galapagos finches are the famous example from Darwin's voyage. Each island of the Galapagos that Darwin visited had its own kind of finch (14 in all), found nowhere else in the world. Some had beaks adapted for eating large seeds, others for small seeds, some had parrot-like beaks for feeding on buds and fruits, and some had slender beaks for feeding on small insects. One used a thorn to probe for insect larvae in wood, like some woodpeckers do. (Six were ground-dwellers, and eight were tree finches.) This diversification into different ecological roles, or niches, is thought to be necessary to permit the coexistence of multiple species. To Darwin, it appeared that each was slightly modified from an original colonist, probably the finch on the mainland of South America, some 600 miles to the east. It is probable that adaptive radiation let to the formation of so many species because other birds were few or absent, leaving empty niches to fill; and because numerous islands of the Galapagos provided ample opportunity for geographic isolation.
Voyage of the Beagle Map
I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection. - Charles Darwin, The Origin of Species
Galapagos finches are the famous example from Darwin's voyage. Each island of the Galapagos that Darwin visited had its own kind of finch (14 in all), found nowhere else in the world. Some had beaks adapted for eating large seeds, others for small seeds, some had parrot-like beaks for feeding on buds and fruits, and some had slender beaks for feeding on small insects. One used a thorn to probe for insect larvae in wood, like some woodpeckers do. (Six were ground-dwellers, and eight were tree finches.) This diversification into different ecological roles, or niches, is thought to be necessary to permit the coexistence of multiple species. To Darwin, it appeared that each was slightly modified from an original colonist, probably the finch on the mainland of South America, some 600 miles to the east. It is probable that adaptive radiation let to the formation of so many species because other birds were few or absent, leaving empty niches to fill; and because numerous islands of the Galapagos provided ample opportunity for geographic isolation.