DARWIN’S FINCHES

Darwin’s Finches Also known as the Galapagos Finches, or the Geospizinae All are roughly the same size, but vary in beak structure Beaks are highly adapted for specific food sources Darwin theorized that these finches were all derived from a common ancestor

Adaptive Radiation Def’n: Diversification of a species into several forms that are each adaptively specialized to a specific environmental niche. Niche: - The function or position of an organism or population within an ecological community, OR The particular area within a habitat occupied by an organism.

How did adaptive radiation occur on the Galapagos Finches? -Several Islands geographically distant enough to keep populations separate Unique environments on and between the islands provided several “niches” for populations to evolve in. Each niche had a slightly different food supply which was the driving force behind the shaping of the beaks -Some finches evolved beaks to crack open large dense seeds from plants in their niche -Others evolved beaks that were adapted to hold and catch tiny insects their niche.

Applying the Data Darwin determined the following postulates in his theory of natural selection: 1.Individuals within a given population vary in their traits 2.Some of these variable traits are heritable and are passed on to offspring 3.More offspring are produced than can survive because of limited resources such as food and nesting sites 4.Individuals with advantageous traits will survive and reproduce