Here we have a population of 100% white seals that only have one allele. This is great, because they all have a chance to survive from predators and/or enemies. The following slides are going to explain in further detail how white seals have an advantage to live.
In many situations when reproduction occurs, there can be a mutation or mutations. Now this mutation(s) can be either good or bad. In this case, it is a negative variation where the genotype and phenotype both contradict the mutation and causes problems.
Overpopulation is the process where seals mate, in order to produce more than can be supported by the environment. They make sure that they have a lot of pups, because they hope a few are able to survive (not all of them survive); this causes overpopulation and it is likely to have mutations.
When they reproduced, they create a mix of both white and gray seals (the gray seals are a mutation). This generates the predator/enemy to be attractive to the gray seal, because gray seals stand out more. In this example, the gray seals tend to get eaten by predators rather than white seals. This makes the gray seals to survive and reproduce less than the white seals.
As time goes on, it is valid to say that white seal are going to pertain dominate and therefore are going to survive more and produce more white seals. This results in the genetic makeup that in this certain environment would possibly only have white seals and leave gray seals to become nonexistent in this area.
In conclusion, the surviving white seals are going to stay and the gray seals are not going to be in that area anymore. This shows evolution, because as time goes on, there is change(s). This is how this ties into natural selection, we see how white seals are better suited to survive in their environment. They have a great fitness level and they can not easily be seen (camouflage).