Answer:
The Geographic barrier would have led to speciation in the finches which started from the founder effect where the finches were brought to other areas of the Galapagos. They were separated geographically so they could not mate with each other. Over time, evolution occurs through natural selection and genetic drift. This leads to the population being so different so they have reproductive barriers and can no longer interbreed. They become different species.
Explanation:
Hope this helps you understand better.
In the winter its color changes to more resemble their <em>winter</em> surroundings, so they are more white, enabling them to blend in better with their white surroundings. In summer, its color changes to more resemble its <u><em /></u><em>summer</em> surroundings, so they are more brown like the rocks and ground around them.
Natural selection allows nature to chose which species survives. Only the fittest get to pass on their genes. And by fittest i mean the ones that are better adapted to the environment.<span />
Its more natural and doesn't have side effects