Yes. Smell helps sharks survive by being able to find food in the vast ocean.
Kittens with the same parents can have many different looks based on the inherited combinations of genes that can occur during sexual reproduction.
What is the difference between a mutation in a somatic cell as compared to a mutation in a reproductive cell?
A mutation in a somatic (body) cell cannot be passed on to the next generation. A mutation in a reproductive cell (egg or sperm) may be passed on to succeeding generations.
An example of a selective advantage is a mutation in houseflies. This mutation makes the insects resistant to the insecticide called DDT. This situation is only advantageous if DDT is being used because the flies with the mutation will have a better chance of survival and reproduction (survival of the fittest).
An example of a selective disadvantage can also be the mutation in houseflies that makes them resistant to DDT. This mutation reduces the growth rate of these flies. If DDT is not present, those flies will be less likely to survive and reproduce because of their smaller size (survival of the fittest).