Question

In the image given below, (b) represents a population formed due to which type of natural selection?

• A. Stabilising selection
• B. Disruptive selection
• C. Normalising selection
• D. Directional selection

Answer 1

The correct option is B Disruptive selection

Natural selection is a process in which the nature favours the survival of organisms with suitable variations, that enables them to survive, reproduce and leave a greater number of progeny.

There are three types of natural selection: stabilising selection, directional selection and disruptive selection.

Disruptive selection/Diversifying selection: When natural selection operates in such a way that individuals at both the extreme values of the trait are favoured and individuals with the mean value of the trait are eliminated, it is called disruptive selection. Consequently, the original population is disrupted into 2 or more separate groups that later evolve into new species.
Hence, the image given in the question represents a population which resulted due to disruptive selection.
Stabilising selection/normalising selection: When natural selection operates in such a way that individuals with mean (average) value of the trait are favoured, it is called stabilising selection.
Directional selection: When natural selection operates in such a way that individuals with extreme value of the trait are favored thereby shifting the curve for the phenotypic character in that direction, it is called directional selection.