Download Rabbit Gene Pool Natural Selection Activity

Name _____________________ Date ___________ Periods ______ Lab Partners ___________________
Rabbit Gene Pool Natural Selection Activity
Objective: Model natural selection in a population of rabbits while reviewing concepts of genotype and phenotype
Background: Review of genetics terms from 7th Grade Science:
Genotype = the genetic information inheritied from parents expressed in a pair of letters such as BB, Bb, bb
Phenotype = the outward expression of a genotype, such as brown, gray or white fur on a rabbit
Homozygous = a purebred genotype with two of the same genes such as BB or bb
Heterozygous = a hybrid genotype with two different genes such as Bb
Scientific Question: What is the result of natural selection?
Materials: brown and white beans, paper bag, plastic cup, pencil and worksheet packet
Procedure Part A: First Generation (No Natural Selection)
1. Write “Rabbit Gene Pool” on a paper bag. Choose who will be the Chooser, Bean Counter, Recorder for the group.
2. Place 10 brown beans and 10 white beans into the bag. This represents the offspring of two gray (heterozygous, Bb
for fur color) rabbits.
3. Without looking into the bag, take out two beans to represent an offspring (each baby has two genes, one from each
parent). DO NOT return the beans to the bag. Write the two letter genotype (BB, Bb or bb) of the beans on the
chart below. Write the phenotype (brown, gray or white) for fur color in the next column.
4. Continue taking the beans out of the bag two at a time until all beans are removed. Tally the number of each type
of rabbit in the table at the bottom of the chart.
First Generation Rabbit Offspring (no natural selection)
Rabbit
#
Genotype of fur
color gene (BB, Bb,
or bb)
Phenotype fur color
gene
(brown, gray or white)
1
2
3
4
5
6
7
8
9
10
Genotype Key
Brown bean = B = gene for brown fur
White Bean = b = gene for white fur
Phenotype Key
BB = brown fur
Bb = gray fur
bb = white fur
Tally of Rabbits with Each Fur Color
Number of Offspring with each Fur Color
First Generation (no natural selection)
Second Generation (after natural selection)
Brown (BB)
Gray (Bb)
White (bb)
Name _____________________ Date ___________ Periods ______ Lab Partners ___________________
Procedure Part B: Second Generation (After Natural Selection)
1. To model natural selection, this will be a forest
environment, like the woods behind the field here
at CMS. You should assume that predators eat all
of the white rabbits, and one half of the gray
rabbits.
2. To show this, lightly cross out all of the white
rabbits and half of the gray rabbits from the First
Generation Rabbit Offspring chart from Part A on
the other side, AND remove the beans representing
these “rabbits” from the from the current gene pool
. Put the beans from these no longer living
“rabbits” into the predator cup.
3. Now we will assume that each surviving rabbit
from the First Generation has a litter of six babies.
To show this, for each First Generation brown
rabbit, count out 12 new brown beans for the
Second Generation (12 beans representing the
genes for six baby brown rabbits). Place these 12
beans plus the two beans for the “mom” brown
rabbit and into the Rabbit Gene Pool bag. This
means a total of 14 brown beans in the gene pool
for each brown rabbit from the First Generation.
4. For each surviving gray rabbit from the First
Generation, put 6 brown beans and 6 white beans
(one of each color gene representing the genes of
the gray “mom” rabbit) into the Rabbit Gene Pool
bag. Also place one brown and one white bean
into the bag representing the gray “mom” rabbit.
5. Repeat steps 3 and 4 from Part A (other side!) and
use the chart to record the second generation of
rabbit offspring. You may not need all 35 lines,
depending upon your First Generation offspring.
6. Tally your results and add to the Tally Table on the
bottom front side of this sheet.
7. Answer analysis questions on the next page using
complete sentences and scientific thinking.
8. We will create a bar chart for the first and second
generation of rabbit offspring showing the three
phenotypes using Excel. This will become part of
your completed project, along with this completed
packet.
Second Generation Rabbit Offspring (Part B)
Rabbit
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Genotype of fur
color gene (BB, Bb,
or bb)
Phenotype fur
color gene
(brown, gray or
white)
Name _____________________ Date ___________ Periods ______ Lab Partners ___________________
Analysis (to be done after completing Second Generation Chart)
The Basics
1. What does each bean represent? ____________________________________________
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2. What does a pair of beans represent? _________________________________________
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3. What do all the beans in the bag represent? ____________________________________
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Observe the Data
4. How did the rabbit gene pool change from the First Generation to the Second
Generation? _____________________________________________________________
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5. What happened to the percentage of white rabbits after natural selection occurred?
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6. What happened to the percentage of brown rabbits after natural selection occurred?
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Think About It
7. If this type of natural selection continues, will the white rabbit gene ever completely die
out? _____ Explain your answer _____________________________________________
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8. How is this model similar to the way natural selection occurs in nature? _____________
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9. How is this model UNLIKE the way natural selection occurs in nature? _______________
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Name _____________________ Date ___________ Periods ______ Lab Partners ___________________
10. Challenge: Think about how the environment may change, and how those changes
could affect natural selection in this population of rabbits. Explain your answer here.
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