Disruptive selection is a type of natural selection that occurs when individuals with extreme values of a trait have higher fitness than individuals with intermediate values of the trait. This can result in the splitting of a population into two or more distinct groups with different traits.

During disruptive selection, the following happens:

1. Extreme values are selected: Individuals with extreme values of a trait are favored by natural selection, while those with intermediate values are disadvantaged. This can happen in a variety of ways. For example, in a population of birds with different beak sizes, individuals with either very small or very large beaks may be better able to feed on different types of food than those with intermediate beak sizes.

2. Intermediate values are less fit: Individuals with intermediate values of a trait may be less able to compete for resources, avoid predators, or find mates, leading to lower fitness.

3. Two or more groups may form: As a result of disruptive selection, the population may split into two or more distinct groups with different traits. For example, in a population of fish with different color patterns, individuals with either very light or very dark coloration may be favored, leading to the formation of two distinct groups.

4. Genetic variation is maintained: Disruptive selection can help to maintain genetic variation within a population, as individuals with different traits are favored in different environments. This can help a population to adapt to changing conditions over time.

Overall, disruptive selection is an important mechanism of evolution that can lead to the formation of new species and the maintenance of genetic diversity within populations.