S
S
C
C
C
C
C
S
D
C
C
C
C
S
P
C
C
C
C
S
C
C
C
C
C
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
w
Nature at Work Skills Lab
(adapted from Prentice Hall Science Explorer Cells & Heredity p. 146-147)
Problem: How do species change over time?
Event Cards:
S card: the mouse survives.
D (disease) or P (predator) card: the mouse dies.
C: the mouse dies if its color contrasts (sticks out) in the environment.
Mouse Cards:
Allele pairs of WW or Ww produce a white mouse
Allele pairs of ww produce a brown mouse
Procedure:
PART 1: A White Sand Environment
Use the mouse cards to model what might happen to a group of mice in an environment of
white sand dunes.
1. Mix up the mouse allele cards.
2. Choose 2 cards. Record the color of the mouse with a tally mark in the data table.
3. Choose an event card. If the mouse lives, put the 2 mouse cards in the “live mice” pile.
If it dies, put the cards in the “dead mice” pile. Record each death with a tally mark on
the data table and put the event card at the bottom of the stack.
4. Repeat steps 2-3 with all the remaining mouse cards to study the first generation of
mice. Record your results.
5. Leaving the “dead mice” cards untouched, mix up the cards from the “live mice” pile
and mix up the events cards.
6. Repeat steps 2-5 through 2 more generations.
Part 1: A White Sand Environment
Generation
1
2
3
Population
White Mice
Brown Mice
Deaths
White Mice
Brown Mice
PART 2: A Forest Floor Environment
1. Predict: How would the data differ if the mice in this model lived on a dark brown forest
floor?
________________________________________________________________________
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2. Repeat the activity using the cards to test your prediction. Remember that a C card now
means that any mouse with white fur will die.
Part 2: A Forest Floor Environment
Generation
Population
White Mice
Brown Mice
Deaths
White Mice
Brown Mice
1
2
3
Analyze and Conclude:
1. In Part 1, which color mouse had the higher death rate in each generation? (To
calculate death rate, divide the number of dead mice of a color by the total number of
mice that color)
In Part 2, which color mouse had a higher death rate in each generation?
2. If the events from Part 1 happened in nature, how would the group of mice change over
time?
3. How did the results in Part 2 differ from those in Part 1?
4. How would it affect your model if you increased the number of C cards?