Is this population in Hardy-Weinberg equilibrium? Why?
A population of 20 deer was introduced to an island where no deer had previously lived. Although there were several bucks (males of breeding age), one was much larger and stronger and was able to fight off the other bucks. The large buck was able to breed with the ten or so females in the breeding population. This same scenario repeated itself for three years in a row.
This probably would not be in Hardy-Weinberg equilibrium. The same "alpha" buck mating successfully with the existing doe population, fending off advances from the other bucks, would be an example of what is known as "non-random mating". In Hardy-Weinberg, predictions are made assuming random mating within a specified gene pool. There are several conditions that would cause the gene pool to become too small and avoid the diversity that Hardy-
Weinberg seeks to predict. Mutation, small gene pool, genetic drift and the above-mentioned nonrandom mating are all contributors to violating the Hardy-Weinberg principle. If this scenario went for one generation, then corrected itself with random mating, allowance could be made that the principle was in equilibrium. But continued repetition within the sam gene pool would not allow for genetic variance and therefore would not contribute to equilibrium.