GIZMOS: Student Exploration: Hardy-Weinberg Equilibrium, Question Answers Guaranteed A+: Latest 2023:2024

Name: David De Souza Date:05/02/2017

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___________________________________________________

Gizmo Warm-up

Many factors—immigration, natural selection, hunting, and

so forth—can influence the composition of a population. To

determine if one of these factors is affecting a population, it

is useful to know what a population looks like when none of

these factors is present.

In 1908, Godfrey Hardy and Wilhelm Weinberg independently discovered the laws that govern

such populations. These laws can be explored in the Hardy-Weinberg Equilibrium Gizmo™.

1. The parrots you see on the SIMULATION pane represent a larger population of 500 parrots.

Select the TABLE tab. How many parrots of each genotype are in the initial population?

DD 250___ Dd 100 dd 150

2. Return to the DESCRIPTION tab. Click Begin, and then click Breed. What happens?

The parrots pair up and probuce eggs

3. Click Hatch, and look on the TABLE tab. What are the parrot populations now?

DD 181 Dd 237 dd 82

Activity A:

Alleles and

genotypes

Get the Gizmo ready:

● On the DESCRIPTION tab, click Reset.

● Check that DD is 50% and dd is 30%.

Question: How will the proportion of genotypes and alleles change over time when

mating is random and no natural selection is occurring?

1. Predict: How do you expect the proportions of D and d alleles to change over time?

I think the proportions are going to decrease over time

2. Gather data: Run a generation in the Gizmo. After clicking Hatch, fill in the allele and

genotype percentages for generation 1. Repeat this process for 5 generations.

Initial

values

Generation

1 2 3 4 5

?lleles 60 60.1 58.8 59.4 59.7 58.3

?lleles 40 39.9 41.2 40.6 40.3 41.7

% of DD genotype 50 36 34.4 32.8 36.8 37.2

% of Dd genotype 20 48.2 48.8 53.2 45.8 42.2

% of dd genotype 30 15.8 16.8 14 17.4 20.6

3. Analyze: What patterns do you see in your data? I realize that the percent of D and d alleles

remain fairly constant while the genotypes change after the first generation and don’t really

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