Genetic equilibrium describes the condition of an allele or genotype in a gene pool (such as a population) where the frequency does not change from generation to generation.However, there are conditions or factors that may alter or disturb the genetic equilibrium in a population.These conditions include; Non-random mating small population size immigration or emigration Mutations (spontaneous random changes that occur in the genome) Natural selection.
Any living or non-living thing that can affect the animal or plant in any way, this can include sunlight and temperature. Or other animals like Predators.