Principle #1 : Genetic Variation : The genetic variation is the red and yellow butterflies.
Principle #2 : Overproduction & the struggle to survive : Butterflies have 2 babies but only 1 survives. The yellow butterflies are struggling to survive due to eagles eating them because of their bright colors.
Principle #3 : Differential Survival & Reproduction : The red butterflies have a higher fitness & therefore will survive & reproduce
Principle #4 : Change in gene pool : There will be more red butterlies in th population.