Final answer:
The Hardy-Weinberg equilibrium describes a non-evolving population where allele frequencies remain constant over time given five strict conditions are met: no mutations, no migration, large population size, random mating, and no natural selection.
Step-by-step explanation:
In the context of the Hardy-Weinberg equilibrium, 'NO evolution' means that the genetic composition of a population and the frequencies of alleles are not changing over time. This is a theoretical concept that relies on five strict conditions being met: (1) No mutation, (2) No migration, (3) A very large population size, (4) Random mating, and (5) No natural selection. Only when all of these conditions are present can a population be considered at Hardy-Weinberg equilibrium and therefore not evolving.
The genetic equilibrium described by the Hardy-Weinberg model is used as a baseline to compare real population changes. If scientists observe that the allele or genotype frequencies in a natural population do not align with the predicted frequencies by Hardy-Weinberg equilibrium calculations, it can be deduced that the population is subject to evolutionary forces, as real populations often are due to factors like genetic drift, selection, and gene flow.