Directional selection is also known as Progressive selection

Directional selection is a type of natural selection in which individuals with traits that deviate from the average are more likely to survive and reproduce. This leads to a shift in the population towards one extreme of the trait, resulting in the gradual evolution of a new phenotype. This process is also known as progressive selection.

Explanation:

Directional selection occurs when individuals with traits that are advantageous in a particular environment have a higher chance of survival and reproduction. This leads to an increase in the frequency of alleles associated with those traits in the population over time. As a result, the population gradually shifts towards one extreme of the trait.

For example, consider a population of birds living in an environment where food sources are becoming scarce due to climate change. Birds with longer beaks may have an advantage in obtaining food from deeper crevices or accessing new food sources. As a result, these individuals have better chances of surviving and reproducing compared to individuals with shorter beaks.

Over time, the frequency of alleles associated with longer beaks increases in the population, while the frequency of alleles associated with shorter beaks decreases. This gradual shift towards longer beaks is an example of directional selection or progressive selection.

Key Points:
- Directional selection is a type of natural selection.
- It occurs when individuals with traits that deviate from the average have a higher chance of survival and reproduction.
- This leads to a shift in the population towards one extreme of the trait.
- Directional selection is also known as progressive selection.
- It results in the gradual evolution of a new phenotype.