Student Exploration: Hardy-Weinberg Equilibrium

Vocabulary: allele, genotype, Hardy-Weinberg equation, Hardy-Weinberg principle,

heterozygous, homozygous, Punnett square

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

Suppose the feather color of a bird is controlled by two alleles, D and d. The D allele results in

dark feathers, while the d allele results in lighter feathers.

1. Suppose two Dd birds mate. What percentages of DD, Dd, and dd

offspring would you predict? Use the Punnett square at right to

help determine your answer.

DD: 25% Dd: 50% dd: 25%

2. In this situation, what ratio of heterozygous (Dd) to homozygous (DD and dd) offspring

would you expect to find? 1:1 ratio of heterozygous (Dd) to homozygous (DD and dd).