Principle #1- Genetic Variation The genetic variation within the lizard population is green lizards and white lizards.
Principle #2 -Overproduction & The struggle for existence Each lizard lays 8 eggs but only a few make it because they are eaten by predators. The white lizards struggle to survive and reproduce because they are more noticeable to predators (eagles,snakes,etc). The green lizards can blend in with the surroundings.
Principle #3- Differential Survival & Reproduction The green lizards can blend in with their environment and be less noticed by eagles flying above. The white lizards stand out around all the green plants and the soil. In this scenario the green lizards have the beneficial trait.
Principle #4- Changes in gene pool In the beginning there were more white lizards than green lizards. Since only a few white lizards made it to the reproductive stage the future generations will contain more green lizards than white lizards.