Hardy Weinberg Principle

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 ) increases in frequency, resulting in a sigmoid curve showing directional selection.