The Mice and the Founder Effect By Galen Sutterlin
The mice lived happily on the shore. They had a great time playing with each other on the beach. They liked where they lived. However, there were not many mice! That made the different types of mice separate and live in different places. They could not keep their species going with other kinds.
One group of mice traveled to the flat lake shore. Their life there was tough at first, but they soon got used to their environment. Because they came from such a small group of mice, their variation was very limited; almost all of the mice were alike!
One day, one of the gray mice came to visit the Black Mice after it got lost. It was unable to reproduce with the other mice because it was so different! The two populations became isolated from one another. The dark mice had created their own population!
The same thing happened with the grey mice. They moved to the river bank, and started their own population. They isolated themselves from the darker mice. They had created a whole new species from the few mice that had moved there.
The same thing happened to one of the dark mice! It lost its way while scavenging for food; it had to stay with the gray mice for a while. Once again, it could not reproduce because the gray mice had started their own separate population. The Founder Effect had a big impact on each colored population!