Download S-B-9-1_Rabbit Natural Selection Laboratory Activity

S-B-9-1_Rabbit Natural Selection Laboratory Activity-Student Version
Rabbit Natural Selection Laboratory Activity―Student Version
Introduction: In this activity, you will examine natural selection in a population of wild rabbits.
Over generations in a population, alleles of genes change in frequency. There is a gene for fur in
rabbits. The presence of fur is dominant to the absence of fur, which is recessive. Rabbits that do
not have fur do not survive as well through cold weather.
In this lab, the dominant allele for fur will be represented by F, and the recessive allele for no fur
will be represented by f. Rabbits that are FF and Ff have fur; rabbits that are ff have no fur.
Materials:

cereal, 50 pieces each of two colors

1 paper bag

3 Petri dishes or containers

3 labels

computer with spreadsheet software, or 1 sheet of graph paper
Procedure:
1. Complete the hypothesis and prediction sections of the lab.
2. Decide which color cereal will represent the allele for fur (F), and which color will represent
the allele for no fur (f).
3. The paper bag represents the environment where the rabbits live and mate. Place all cereal
pieces inside the bag.
4. Label the Petri dishes: FF (for homozygous dominant), Ff (for heterozygous), and ff (for
homozygous recessive).
5. Shake the bag to simulate the rabbits mating. Without looking, select two alleles at a time.
Place the rabbits (pairs of alleles) in the appropriate dish: FF, Ff, or ff. Record the results in
the data table next to “Generation 1.” For example, if you draw colors represented by Ff,
place a tally mark under “Number of Ff individuals.” Note: The total number of individuals
will be half the total number of beans because each rabbit has two of the alleles.
6. Rabbits with the ff genotype have no fur. The cold weather kills them before they can
reproduce, so they can’t pass on their genes. Place the alleles from the ff dish aside before
beginning the next generation.
7. After each generation, place the alleles of the surviving rabbits back into the bag and mate
them again. Continue drawing pairs of alleles and recording the results in the data table until
all the alleles have been selected and sorted into dishes.
8. In your data table, count the F and f alleles that were placed in the FF and Ff dishes. Record
the numbers in the chart in the columns labeled “Number of F Alleles” and “Number of f
alleles.” Note: Do NOT count the alleles of the ff rabbits because they are dead.
S-B-9-1_Rabbit Natural Selection Laboratory Activity-Student Version
9. For each generation, add up the number of F alleles and the number of f alleles, and record
the number in the “Total Number of Alleles” column.
10. Calculate the gene frequency of F and f for each generation and record them in the chart in
the “Gene Frequency F” and “Gene Frequency f.” To find the gene frequency of F, divide the
number of F alleles by the total number of alleles. To find the gene frequency of f, divide the
number of f alleles by the total number of alleles. Record the results as decimals, rounding
each one to the hundredths place (e.g., 0.75).
11. Create a double-line graph of the frequencies of F and f. Label the x-axis, “Generation” and
the y-axis, “Frequency in Decimals.” Include a legend for the graph that shows the difference
between the lines for F and f frequencies; use different colors or solid and dashed lines.
12. Complete the Analysis and Conclusions sections with your group.
Hypothesis: Write a hypothesis about how the frequency of dominant and recessive alleles in a
population may change over several generations.
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Prediction: Based on your hypothesis, write a prediction about the frequency of F alleles and f
alleles in the rabbit population after 10 generations. (Rabbits with the ff genotype in each
generation do not survive.)
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S-B-9-1_Rabbit Natural Selection Laboratory Activity-Student Version
Data Table:
Generation
# of FF
# of Ff
# of ff
Number Number Total
Gene
Gene
individuals individuals individuals
of F
of f
Number Frequency Frequency
Alleles Alleles
of
of F
of f
Alleles
1
2
3
4
5
6
7
8
9
10
Analysis:
1. Do your results support your hypothesis? Why or why not?
2. Compare the changes in the number of F alleles with the number of f alleles over the
generations.
3. Compare the frequencies of the dominant allele F with the frequencies of the recessive allele
f.
4. How could you change this activity to simulate rabbits migrating to the rabbit population?
5. How could rabbit migration affect the allele frequencies?
Conclusion: Based on your results in this activity, explain how natural selection can impact the
allele frequencies of a population.