How does natural selection act on genetic variation?

Natural selection acts on genetic variation by favoring individuals with traits that increase survival and reproductive success in a given environment. These advantageous traits are often the result of genetic differences (alleles) present within a population.

When variation exists, some individuals are better adapted to environmental conditions. These individuals are more likely to survive, reproduce, and pass their beneficial alleles to the next generation. Over time, the frequency of these advantageous alleles increases in the population.

Natural selection can operate in different ways:

• Directional selection favors one extreme phenotype

• Stabilizing selection favors intermediate traits

• Disruptive selection favors multiple extreme phenotypes

The process depends on environmental pressures such as climate, availability of resources, predators, and competition. If conditions change, the traits that are advantageous may also change.

Importantly, natural selection does not create variation; it acts on existing genetic variation produced by mutations and recombination.

Overall, natural selection shapes populations over generations by increasing the prevalence of beneficial traits and reducing less favorable ones, driving evolution.