gen-state-the-hardy-weinberg-principle-precisely-and-explain-why-4e0d

State the Hardy-Weinberg principle precisely and explain why it matters in 2-3 sentences.

## Hardy-Weinberg Principle **Precise Statement:** In a large, randomly mating population free from mutation, migration, and natural selection, allele frequencies remain constant across generations, and genotype frequencies can be predicted as p² + 2pq + q² = 1 (where p and q are the frequencies of two alleles). **Why It Matters:** The Hardy-Weinberg principle serves as a null hypothesis for evolution—it describes the conditions under which populations do *not* evolve, allowing scientists to identify when evolutionary forces (selection, drift, mutation, migration, or non-random mating) are acting on real populations. By comparing observed genotype frequencies to Hardy-Weinberg expectations, researchers can detect evolution in action and measure its magnitude.