Principle #1- There are two types of mice in this population, Some mice have white fur while others have dark green fur, this is called Genetic Variation. Genetic Variation is when a population of organisms have different traits.
Principle #2- Over production and the struggle for Existence is the fact that the mice will produce more offspring than what the environment can support.
Principal #3- Differential survival and reproduction The mice with dark green fur have higher fitness because they are camouflaged with their environment, unlike the mice with white fur, because the mice with dark fur are well camouflaged they are less likely to be eaten by predators and more likely to reproduce.
Principal #4-Gene pool is simply the genotype of all organisms in a population. In this case the Gene pool changed. The population started with 4 pale mice and 4 dark mice, and the population ended with 2 white mice and 8 dark fur mice, the frequency changed because the dark fur mice had an advantage over the white fur mice.