Speciation
Sometimes natural selection can give rise to an entirely new species. This process is called speciation. Through speciation, two species arise from one. A new species is formed when some members of a population become so different that they can no longer breed with other members to produce fertile offspring. One way that this happens is when two populations of the same species become geographically isolated.
For example, in the Galapagos Islands, different populations of finches lived on different islands. Each population had a slightly different environment and so different traits were selected for on each island. They were all originally the same species, but after living apart for long periods of time, new species developed on each island. Here you see different finch species, each one living on a different island. They gradually developed different beaks over time because each one had a slightly different environment and food choices.
