Final answer:
Mutations are heritable changes in DNA that can lead to noticeable changes in an organism's phenotype. These changes can result from alterations in protein structure or affect the organism's fitness. Mutations contribute to genetic diversity and can have various outcomes on an organism's phenotype.
Step-by-step explanation:
A mutation is a heritable change in the DNA sequence of an organism. This change can result in a recognizable change in phenotype compared to the wild type. Mutations in DNA can lead to altered amino acid sequences in proteins, which can ultimately affect the organism's phenotype. For example, a mutation in the gene responsible for producing melanin can lead to a change in pigmentation, resulting in a different phenotype for an organism.
This change in phenotype can have various outcomes. Some mutations may have a negative effect on an organism's fitness, reducing its likelihood of survival or producing fewer offspring. Other mutations may have a beneficial effect on fitness, providing an advantage to the organism. There are also neutral mutations that have no effect on an organism's fitness.
Overall, mutations contribute to genetic diversity in populations and can lead to noticeable changes in an organism's phenotype, affecting its appearance, behavior, and other traits.