Question

How does the process of Natural Selection affect Hardy-Weinberg equilibrium? Explain with the help of graphs.

Hint:

Hardy-Weinberg equilibrium is maintained only in the absence of evolutionary forces. Natural selection is one of the major forces that causes deviation.

Answer 1

Natural selection disrupts Hardy-Weinberg equilibrium by favoring certain alleles over others, leading to changes in allele frequencies.
Hardy-Weinberg assumes no evolution, but selection creates a differential reproductive success. 
Graphically:

• The equilibrium predicts constant allele frequencies: a horizontal line.
• Under natural selection, a beneficial allele (say \( A \)) increases in frequency, resulting in a sigmoid curve showing directional selection.