Final answer:
Mutation in an organism's DNA may result in increased fitness, decreased reproductive success, contribute to genetic diversity, or have no effect on the phenotype. Mutations play a key role in genetic diversity, with outcomes ranging from beneficial to neutral, affecting the organism's fitness differently.
Step-by-step explanation:
If a mutation in the DNA of an organism results in a change in the organism's physical characteristics, or phenotype, there can be several possible outcomes. One outcome could be increased fitness, where the mutation gives the organism a beneficial trait that enhances its survival and reproduction in its environment. Another possibility is that the mutation could lead to decreased reproduction, meaning the organism's ability to produce offspring is impaired, ultimately affecting its fitness negatively.
Furthermore, mutation is a key factor in contributing to genetic diversity within a population, as it introduces new genetic variations. However, not all mutations have an impact on the organism's phenotype or its reproductive success; many are neutral mutations and result in an unchanged phenotype. Variations in phenotype caused by mutations may range from negligible to significant, affecting the organism’s fitness to varying degrees. Sexual reproduction also significantly contributes to genetic diversity, through the unique combination of alleles from each parent.