Isolation by distance

Isolation by distance is a way of explaining how different populations of animals or people can become different from each other over time even though they started from the same group. It works like this: animals or people that are far away from each other have less chance of meeting and exchanging genes, so as time passes, the animals or people living in different places will become more and more different from each other. This is why some animals or people living far away look or think or act differently, even though they started out the same!