GIZMOS Student Exploration Hardy-Weinberg Equilibrium ( Version 1)

Name: Fatima Date: Monday, January 8, 2018



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.




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DD 25% Dd 50% dd 25%




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2. In this situation, what ratio of heterozygous (Dd) to homozygous (DD and dd) offspring
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would you expect to find? 50:50
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Gizmo Warm-up
Many factors—immigration, natural selection, hunting, and
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so forth—can influence the composition of a population. To
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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.
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In 1908, Godfrey Hardy and Wilhelm Weinberg independently discovered the laws that govern
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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?
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DD 174 Dd 100 dd 150
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2. Return to the DESCRIPTION tab. Click Begin, and then click Breed. What happens?
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The parrots pair up, produce eggs and then fly away.


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

DD 174 Dd 240 dd 86



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, Activity A: Get the Gizmo ready:
Alleles and  On the DESCRIPTION tab, click Reset.
genotypes  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?

There will be more D alleles than d.


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 Generation




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values




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1 2 3 4 5




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% D alleles 60 60.3 61.7 61.7 63.0 61.4




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% d alleles 40 39.7 38.3 38.3 37.0 38.6




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% of DD genotype 50 35.8 38.0 39.0 39.6 38.0
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% of Dd genotype 20 49.0 47.4 45.4 46.8 46.8
% of dd genotype 30 15.2 14.6 15.6 13.6 15.2
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3. Analyze: What patterns do you see in your data? The percentages of D alleles and d alleles
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remain fairly constant throughout the simulation.

4. Interpret: Select the ALLELE GRAPH tab. What does this graph show? The graph shows
that the percentage of D alleles are higher as the next generation starts. The percentage of
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d alleles lower as the next generation starts.
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5. Interpret: Select the GENOTYPE GRAPH tab. What does this graph show? The genotype
graph shows that the percentage of Dd genotypes made a big jump from generation 0 to 1
and went lower and then higher. The DD genotypes dropped a lot from generation 0 to 1 and
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went higher. The dd genotypes also dropped a lot and then went higher and lower.
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(Activity A continued on next page)
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This study source was downloaded by 100000809733538 from CourseHero.com on 05-13-2021 18:14:07 GMT -05:00


https://www.coursehero.com/file/61622107/Hardy-Weinberg-Equilibrium-Gizmo-Fatimadoc/