Disruptive selection, also known as diversifying selection, is a type of natural selection that occurs when extreme traits are favored over intermediate traits. This can lead to the formation of two or more distinct peaks in the frequency distribution of a trait.

Two peaks in Disruptive Selection

In disruptive selection, there are two peaks in the frequency distribution of a trait. This is because extreme traits are favored over intermediate traits, leading to the formation of two distinct groups with different trait values. The two peaks represent the two different groups that have evolved due to this selective pressure.

Example of Disruptive Selection

An example of disruptive selection can be seen in the beak size of a bird species that feeds on different-sized seeds. Birds with large beaks are better able to crack open large seeds, while birds with small beaks are better able to crack open small seeds. Intermediate beak sizes are not as effective at cracking either type of seed. Over time, this can lead to the formation of two distinct groups of birds with either large or small beaks.

Conclusion

In conclusion, disruptive selection leads to the formation of two peaks in the frequency distribution of a trait, representing the two distinct groups that have evolved due to selective pressure. This is an important mechanism in the evolution of species and can lead to the formation of new species over time.