Principle 2 : Overproduction and the Struggle to Survive
Principle 3 : Differential Survival and Reproduction ( survival of the fittest )
Genetic variation is the difference in the alleles. In this case it would be the ability to camouflage the seals fur with the icebergs.
Principle 4 : Change in the Gene Pool
The struggle to survive is being able to protect yourself from predators. An animal can do this by physical or behavioral adaptations.
organism : seal environment : water trait selected : skin adaptation : physical ( camoflouge )
Survival of the Fittest in a population is the animals who are able to use their traits to survive predators. This shows that the shark killed the seal that had gray skin.
Finally, the Change in the Gene Pool are mutations that occur over time. In this scenario the new generations have white seals because the gray seal couldn't reproduce. Even though this is true, they still might have the gray skin allele.