GIZMOS: Student Exploration: Hardy-Weinberg Equilibrium, Question Answers (Version 4)

Name: ______________________________________ Date: ________________________



Student Exploration: Hardy-Weinberg Equilibrium

Vocabulary: allele, genotype, Hardy-Weinberg equation, Hardy-Weinberg principle,
heterozygous, homozygous, incompletely dominant, Punnett square


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

1. A bird’s feather color is controlled by two alleles, D (dark feathers) D DD Dd
and d (lighter feathers). 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 dd




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d




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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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rs e
would you expect to find? ___3:1______________________________________________
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Gizmo Warm-up
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Many factors—immigration, natural selection, hunting, etc—can
influence the composition of a population. To determine if one of
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these factors is affecting a population, it is useful to know what a
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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.
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1. The parrots you see represent a population of 500 parrots. For these parrots, the D allele is
incompletely dominant over d, which means that Dd parrots are intermediate between DD
and dd parrots. In the Gizmo, select the TABLE tab. How many parrots of each genotype
are in the initial population?
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DD _250_ 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 breaded and laid eggs.


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

DD _169___ Dd __253_____ dd _78___



2019
This study source was downloaded by 100000809733538 from CourseHero.com on 05-13-2021 18:19:32 GMT -05:00


https://www.coursehero.com/file/83672201/Hardy-Weinberg-Gizmodocx/

, 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?

__I believe there will be a higher percentages of D alleles and a lesser percentage of d
alleles.


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.




m
Initial Generation




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values 1 2 3 4 5




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% D alleles 60 60.8 60.7 59.5 61.9 62.2




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% d alleles 40 39.2 39.3 40.5 38.1 37.8
% of DD genotype rs e 50 36 35.4 34.6 40 39.4
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% of Dd genotype 20 49.6 50.6 49.8 43.8 45.6
% of dd genotype 30 14.4 14 15.6 16.2 15
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3. Analyze: What patterns do you see in your data? __The percentages usually decrease in
the second and third generations then go up in the fourth generation and finally go down in
again in the fifth generation.
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4. Interpret: Select the ALLELE GRAPH tab. What does this graph show? _There was a small
increase in the D alleles and a small decrease in the d alleles.
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5. Interpret: Select the GENOTYPE GRAPH tab. What does this graph show? __There was a
30% increase for the Dd genotypes and about a 25% decrease in DD and dd genotypes.
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(Activity A continued on next page)
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2019
This study source was downloaded by 100000809733538 from CourseHero.com on 05-13-2021 18:19:32 GMT -05:00


https://www.coursehero.com/file/83672201/Hardy-Weinberg-Gizmodocx/