Why were Darwin's finches different on each island?
1 Answer
Adaptive evolution due to natural selection of existing possible variations within the genome of the finches DNA.
Explanation:
Each island has a different environment. The differences in environment selected different variates from the possibilities of the DNA in the finches.
Also within a given island there are different niches. For example on the same island there are three different species of ground finches.
rThere are the small beak finches medium beak ground finches and large beak ground finches. Each species specialize in different types of seeds. Generally these different species because of their different feeding and nesting habits do not interbreed.
In a series of dry seasons the differences in beak size increases causing further separation of the different types of finches. However in wet seasons when there is a surplus of seeds the different types of finches interbreed forming hybrids and the differences in beak sizes are reduced.
The stresses of the environment select different types of finches to be favored.
