Principle #1 Genetic Variation: The Genetic Variation with in the beetle population is that their are black beetles and brown beetles.
Principle #3 Overproduction and the Struggle for existence: Overproduction: The black beetles produce about 400 but only 100 make it and the brown beetles produce about 600 at a time most of them make it. Struggle to survive: That the black beetles are seen easier by the birds because they can not camoflauge with the sandy brown enviorment. However the brown beetles can camoflauge and are raley eaten by the birds.
Principle #3 Differential Survival and Reproduction: The brown beetles are producing more than ever because of the birds eating the black beetles witch means they harley can produce black beetles.
Principle #4 Changes in the gene pool: The change is that the surperior trait has been passed down to future generations witch is the brown beetles because of the camoflauging trait they have for that enviorment.