Final answer:
A DNA mutation can change an organism's phenotype by altering the amino acid sequence of proteins, which may affect the organism's physical characteristics, behavior, or health. Mutations impact fitness in varying degrees, with some reducing, increasing, or having no effect on an organism's survival and reproduction. This genetic variance is a key element in natural selection and the evolution of species.
Step-by-step explanation:
When a DNA mutation occurs, it is a heritable change in the DNA sequence that can alter the phenotype of an organism. Phenotype refers to observable characteristics, which are largely determined by proteins that carry out cellular functions. If a mutation changes an amino acid in a protein, this can lead to an altered phenotype
. For example, a mutation could result in a protein that changes the color of an organism's eyes, the texture of its hair, or even its susceptibility to certain diseases.
These mutations have different effects on an organism's fitness. Some may reduce an organism's likelihood of survival or reproductive success, while others may be advantageous, increasing an organism's fitness. Moreover, there are neutral mutations that have no significant impact on the organism's phenotype or fitness.
The range of effects that a mutation can have on phenotype can vary greatly, from minor to substantial; this variance plays a crucial role in the process of natural selection, which can lead to evolution over time.
Finally, mutations are the ultimate source of genetic diversity in a population, with sexual reproduction further contributing to this diversity. Unique combinations of alleles are produced during reproduction, leading to new genotypes and potentially new phenotypes in the offspring.