Principle #1 Genetic Variation: The two types of dolphins are light and dark. The light have the color of the ocean so they camouflage perfectly.
Principle #2 overproduction & the Struggles for existence: The orcas are one of the greatest predators of the dolphins. Also, the light dolphins produce two babies every three months The dark have a less chance of surviving because they don't blend in whereas, the light ones do.
Principle #3 Differential Survival and Reproduction: The light dolphins have a higher fitness so they can survive and reproduce.
Principle #4 Changes in Gene Pool: The light dolphins have the advantageous traits that are going to be passed on to their future offsprings.