Final answer:
The Hardy-Weinberg principle of equilibrium states that genotypes are in Hardy-Weinberg equilibrium if there is random mating and no other forces alter allele proportions. This principle provides a baseline to compare real population changes.
Step-by-step explanation:
The Hardy-Weinberg principle of equilibrium states that genotypes are said to be in Hardy-Weinberg equilibrium if there is random mating and no other forces tend to alter the proportions of alleles from one generation to the next. This principle describes the genetic makeup of a population under certain conditions that include no mutations, migration, emigration, or selective pressure for or against genotype, plus an infinite population size. The Hardy-Weinberg principle provides a mathematical baseline of a non-evolving population against which real population changes can be compared.