Q.How does Hardy-Weinberg’s expression (p2+2pq+q2=1) explain that genetic equilibrium is maintained in a population? List any four factors that can disturb the genetic equilibrium.

Step 1. For a gene with two alleles A (frequency p) and a (frequency q), p + q = 1, and under random mating the genotype frequencies of the next generation are given by expanding $(p+q)^2 = p^2 + 2pq + q^2 = 1$, where p² = frequency of AA, 2pq = frequency of Aa, and q² = frequency of aa.

Step 2. If a population's genotype proportions match this equation and stay unchanged generation after generation, the population is said to be in Hardy–Weinberg equilibrium — meaning its allele frequencies are neither increasing nor decreasing, i.e. it is not evolving at that gene.

Step 3. This equilibrium can only hold if five conditions are simultaneously true: no mutation, random mating, no gene flow (no immigration/emigration), an effectively infinite population size, and no natural selection. …

State the equation's meaning (stable genotype ratios under no disturbing force) and then list four of the five Har …

• Treating the equation itself as proof that a population IS evolving, rather than the reverse (it proves a population is NOT evolving when it holds). …