GIZMOS Student Exploration Hardy-Weinberg Equilibrium-Science 101 -Chamberlain Highschool (Version 2)

Name: Angelica Riviezzo 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.)

1. A bird’s feather color is controlled by two alleles, D (dark feathers)
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.




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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? 1:1
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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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Two birds are randomly matched together and reproduce.

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

DD 168 Dd 256 dd 76




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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?

The d and D alleles will combine and take over the population as it will become the majority

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
values 1 2 3 4 5




m
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% D alleles 60 60.1 60.1 59.4 60.0 61.2




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% d alleles 40 39.9 39.9 40.6 40.0 38.8
% of DD genotype 50 34.0 34.8 35.8 36.4 39.2




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% of Dd genotype rs e 20 52.2 50.6 47.2 47.2 44.0
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% of dd genotype 30 13.8 14.6 17.0 16.4 16.8
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3. Analyze: What patterns do you see in your data? The percent of D and d alleles stay
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consistent but the % of dd alleles and DD alleles start to increase a bit.
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4. Interpret: Select the ALLELE GRAPH tab. What does this graph show?
A consistent graph of DD and dd alleles.
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5. Interpret: Select the GENOTYPE GRAPH tab. What does this graph show?
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DD and dd alleles start to decrease in percentage while the heterozygous alleles start to
increase immediately

(Activity A continued on next page)
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This study source was downloaded by 100000809733538 from CourseHero.com on 05-13-2021 18:15:58 GMT -05:00


https://www.coursehero.com/file/32331498/Gizmo-Hardy-Weinburgdoc/