Download Name Date ______ Mrs. Geithner-Marron (Biology200) Period

Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________
Breeding Bunnies (Allele Frequency & Evolution) Lab

Problem
o To model how natural selection affects the allele frequency of a population over several
generations.

Background Information
o Evolution (on a genetic level) can be described as the change in the allele frequencies of a
population's gene pool over time.

"Selective forces" (ex. breeders, predators, etc.) can select for or against specific
phenotypes (traits) and cause a change in the frequencies of the alleles that produce
those phenotypes (traits).

Changes in allele frequency (and, therefore, evolution), will in turn, affect how often
you see a particular phenotype (trait) in a population.
o Ex. Breeders of rabbits have long been familiar with a variety of genetic traits
that affect the survivability of rabbits in the wild, as well as in breeding
populations. One such trait is the trait for furless rabbits (naked bunnies). This
trait was first discovered in England by W.E. Castle in 1933. The furless rabbit
is rarely found in the wild because the cold English winters are too harsh for the
rabbits and act as a "selective force" against being furless. These rabbits are
not well adapted to their environment and, therefore, die before reproducing
(and passing on their genes).

Vocabulary
o allele ________________________________________________________________
____________________________________________________________________
o gene pool _____________________________________________________________
____________________________________________________________________
o allele frequency ________________________________________________________
____________________________________________________________________
o evolution _____________________________________________________________
____________________________________________________________________
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________

Pre-Lab Questions
1. Let: F (red/brown bean) = furry
f (white bean) = NO fur (furless)
a. Circle the genotype(s) that best fit(s) the description:
i. heterozygous
FF
Ff
ff
ii. homozygous dominant
FF
Ff
ff
iii. homozygous recessive
FF
Ff
ff
iv. have fur
FF
Ff
ff
v. furless (NO fur)
FF
Ff
ff
2. Which phenotype is best adapted for the cold climate of Connecticut? ________________
3. What will happen to the (frequency of the) genes of bunnies that are not well adapted to
survive in the cold? ______________________________________________________
4. What does each individual bean represent? ____________________________________
5. Why do you need to remove two beans for each individual bunny? ____________________
____________________________________________________________________
6. What is the shaking of the bag of beans meant to simulate? _______________________
7. What is the independent variable in this investigation? ___________________________
8. What is the dependent variable in this investigation? _____________________________
9. What is the best type of graph (bar, circle, line) to show the change in allele frequency over
time? ________________________________________________________________

Hypothesis
o If rabbits with fur and NO fur (furless) breed randomly over time in Connecticut, then the
allele frequency for (fur → F / NO fur → f) will (increase / decrease), because _______
____________________________________________________________________
____________________________________________________________________.
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________

Experimental Design
o Materials (per group)
 50 red/brown beans (to represent the F allele for fur)

50 white beans (to represent the f allele for No fur/furless)

1 paper bag (to represent the countryside where the bunnies randomly mate)

4 cups (labeled FF-furry, Ff-furry, ff-No fur/furless, & “dead bunnies”) (to sort bunnies)
o Procedure
1. Place 50 red/brown and 50 white beans (alleles) in the paper bag. (This may have been
done for you already).
2. Shake the paper bag (random mating of the rabbits).
3. WITHOUT looking, select TWO (2) beans from the bag (to represent one offspring).
a. The color of the beans will tell you whether you have a homozygous dominant
(furry), a heterozygous (furry), or homozygous recessive (furless/NO fur) bunny.
4. Place the "bunny" in the appropriate cup (labeled FF-furry, Ff-furry, & ff-furless/NO
fur) based on its genotype.
5. Continue until there are no more beans in the bag.
6. For each cup (FF, Ff, & ff), count how many pairs of beans you have & write the
number of pairs in the correct column (FF, Ff, & ff) in the row next to "generation 1".
7. IMPORTANT!!! The ff bunnies are born furless. The cold weather kills them before
they reach reproductive age, so they can't pass on their genes (alleles).
a. Place the beans from the ff container in the “dead bunny” cup before
beginning the next round. Do NOT put them back in the bag or mix them with
the beans in the Ff or FF cups!!!
8. To figure out the “Surviving # of ‘F’ alleles”: count the remaining red/brown (F)
beans (from the FF and Ff cups) and record the number in the chart in the column
labeled "Surviving # of ‘’F’ Alleles" (column 4)
9. To figure out the “Surviving # of ‘f’ alleles”: count the remaining white (f) beans
(from the Ff cup) and record the number in the chart in the column labeled "Surviving
# of ‘f’ Alleles" (column 5)
a. REMEMBER; don't count the alleles of the ff bunnies that you put aside, because
they are dead.
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________
10. Add the "Surviving # of ‘’F’ Alleles" (column 4) & "Surviving # of ‘f’ alleles" (column
5) for the first generation. Record this number in (column 6) labeled "Total Number of
Surviving Alleles".
11. Place the alleles of the rabbits (FF furry & Ff furry) which have survived, grown, &
reached reproductive age back in the paper bag.
12. Repeat steps 2 through 11 for each generation (until you have finished all 10
generations or you were told to stop).
a. If working as a team, make sure everyone in the group has a chance to select
beans and record results. Nobody should do the same job the entire time.
13. Using the formulas below, determine the allele frequency of F and f for each
generation and record them in the chart in the columns labeled "Frequency of F alleles"
(column 7) and "Frequency of f alleles" (column 8).
a. To find "Frequency of F alleles" (column 7):
allele frequency of F =
"surviving" # of F alleles from column 4
________________________________________________
total # of alleles from column 6
b. To find "Frequency of f alleles" (column 8):
allele frequency of f =
"surviving" # of F alleles from column 5
________________________________________________
total # of alleles from column 6
c. Express results in decimal form (rounded to the nearest hundredth).
d. NOTE: The sum of the frequency of column 7 ‘F' + column 8 ‘f’ should = 1 (for
each generation).
14. Using the attached graph paper, graph your frequencies for both alleles on the same
graph.
a. Remember, the IV goes on the X-axis & the DV goes on the Y-axis.
b. Don't forget to include all the features of a good graph.
15. As a group (or a class), discuss the "Discussion/Thought Questions".
16. Complete the "Analysis and Conclusions".
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________

Observations and Data
Table 1 (Note: columns 7 & 8 should = 1.0)
column 1
column 2
column 3
column 4
column 5
column 6
column 7
column 8
How to figure out
what to do for
each column. →
count PAIRS
of red beans
count PAIRS of
red/white beans
count PAIRS
of white beans
Count all
remaining red F
beans (from FF &
Ff cups)
Count all
remaining white
beans (from Ff
cup)
column 4 + column 5
column 4 / column 6
column 5 / column 6
generation
#FF
bunnies
#Ff
bunnies
#ff
bunnies
"surviving"
# F
alleles
"surviving"
# f
alleles
total # of
"surviving"
alleles
frequency
of F alleles
frequency
of f alleles
(red beans)
(white beans)
(F + f alleles)
(decimal rounded
to hundredth)
(decimal rounded
to hundredth)
1
2
3
4
5
6
7
8
9
10
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________

Discussion/Thought Questions (These questions may be discussed in small groups or as a class. You can use
this space to jot down your thoughts.)
1. How is this lab simulation a model for evolution?
2. What are some limitations (drawbacks) of this type of model?
3. In real life habitats, animals often move in (immigrate) or move out (emigrate). How might
immigration and emigration affect the allele frequencies in a population?

Analysis and Conclusions (Answer # 3-8 in complete sentences. Use another piece of paper if necessary.)
4. In generation 1, what was the frequency of F alleles? _________ ...of f alleles? ________
5. In your last generation, what was the frequency of F alleles? ______ ...of f alleles? ______
6. Did either of the alleles totally disappear? Why/why not?
7. Restate your original hypothesis (from the bottom of page 2).
8. Describe the trends you observed in your data. (Ex. What increased? What decreased?)
(Refer to your data and graph.)
9. Does the data you collected support or refute (not support) your hypothesis? Explain your
reasoning. (Refer to your data.)
10. How does natural selection (for beneficial traits and against traits that are not beneficial)
affect allele frequency?
11. Do individuals or populations evolve? Explain your reasoning.
12. If you were to repeat this lab, how could you add immigration and emigration factors?
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________
Use this sheet to construct your graph.
(title) ___________________________________________________________
(Y-axis) _____________________________________________________

(X-axis label) ________________________________________________________
Name _____________________________________
Date _________
Mrs. Geithner-Marron (Biology200)
Period ________
Extra sheet--Use ONLY if needed (ex. If you made a mistake on the other side).
(title) ___________________________________________________________
(Y-axis) _____________________________________________________

(X-axis label) ________________________________________________________