The Hardy-Weinberg Equilibrium can be disrupted in a population in four main ways. One is that nonrandom mating is happening. Another is that genetic drift can occur, or migration of some of the population. The last way is through natural selection; mainly genetic mutations. Recurring mutation is the ultimate source of variability for a population, but to upset genetic equilibrium it usually has to interact with at least one of the other factors. All the other ways can alter genetic equilibrium on their own.
Work Step by Step
A population can depart from the Hardy-Weinberg Equilibrium in the event of four different factors.