Teddy Graham Lab (Essential Standard 3.4.2)
Story: You are a bear-eating monster. There are two kinds of bears: Happy Bears and Sad
Bears. You can tell the difference between them by the way they hold their hands. Happy Bears
hold their hands high in the air, and Sad Bears hold their hands down low. Happy Bears taste
sweet but are difficult to catch because of their excited energy. Sad Bears taste bitter but
are easy to catch because they move about slowly. Because of this, you eat only Sad Bears.
Procedure:
1) Obtain a plastic bag with a population of 20 bears. COUNT the total number of happy
bears and sad bears and record in Table A.
2) Eat THREE sad bears. If you don’t have three, eat what you have in sad bears. It is now
time for your bears to hibernate through the winter, when they awake they will
reproduce to make offspring that look just like themselves. Use the bears you have to
represent the next generation.
3) Bring the population back to 20, by grabbing THREE new bears from the bowl up front.
Record the TOTAL number of happy and sad bears in the chart.
4) Repeat steps 2 &3 for 5 more generations. REMEMBER to always record your data in
Table A.
5) Graph your results, time verses percent of happy bears on the graph
6) Answer the Extension Questions
TABLE A
# of Happy
Bears
Generation 1
Generation 2
Generation 3
Generation 4
Generation 5
Generation 6
# of Sad
Bears
TOTAL # of
Bears
% of Happy Bears
Teddy Graham Lab (Essential Standard 3.4.2)
Change in Population of Happy Bears
100
Percent of Happy Bears
90
80
70
60
50
40
30
20
10
0
Generation 1 Generation 2 Generation 3 Generation 4 Generation 5 Generation 6
Time
Extension Questions:
1) What happened to the population of bears over time? The happy bears? The sad bears?
2) What caused the population of each type of bear to change?
3) How does this compare with your hypothesis?
4) Predict what would happen if the monster continued to eat only sad bears?
5) Predict what would happen if the monster decided to eat only happy bears?
*WHAT CAUSED NATURAL SELECTION TO OCCUR?
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