Oh Deer!
Preparation: On notebook paper, complete the following:
1. Design a data table that will keep track of up to 20 generations.
The example below has the first 2 generations set up for you.
Deer
Generation
1
2
# of
Wolves
1
# of
Deer
# of Deer
eaten
Deer
Remaining
Deer
Offspring
Wolf
Starved
Wolf
Surviving
3
Procedure:
1. Begin the simulation by populating the habitat with three deer. Do
this by randomly tossing the “deer” into the forest. THERE SHOULD
ALWAYS BE AT LEAST 3 DEER IN YOUR FOREST because new deer
are immigrating into the forest.
2. Next, randomly toss one wolf into the forest in an effort to capture
(land on any portion of) as many deer as possible. In order to survive
and reproduce, the wolf must capture at least three deer.
**if the wolf does not capture enough food it dies, there should
always be at least 1 wolf in your forest because new wolves are
immigrating into the forest.
3. Remove any deer that have been captured and enter data for
generation one.
4. Each surviving deer reproduces one offspring, so the number of
remaining deer in generation 1 will double to be the starting number
of generation 2.
5. If one wolf catches 6 deer, they reproduce 2 offspring, 9=>3 etc.
6. Once your deer population reaches 20, randomly toss in a limiting
factor card. Remove the deer affected by this factor, then toss in your
wolf.
**Add an additional limiting factor ever 10 deer over 20 (30 deer=2
Limiting factor cards, 50 deer=4, etc)
7. If two wolves land on the same deer, the wolf your tossed in first is
the one who eats it.
8. REMEMBER TO ALWAYS RECORD YOUR DATA CAREFULLY AND
ACCURATELY.
Wolf
Offspring
GRAPHICAL ANALYSIS:
1. For each animal make a plot (make a graph) of population totals (the
first two columns) versus generation number. By plotting the deer
population and the wolf population side by side on the same graph,
the relationship between the two becomes clear.
ANALYSIS QUESTIONS:
Answer the following questions on your notebook paper below the data
table you have constructed (this is a lab grade, please be through in your
answers) Use complete sentences:
1. Based on your data, make some observations about the
relationship between the population size of wolves and deer to
formulate a HYPOTHESIS about this relationship.
2. Explain how you tested your hypothesis.
3. When did the deer reach carrying capacity? When did the wolves
reach carrying capacity? How do you know?
4. Identify the predator. What is the predator’s food source?
5. Identify the prey. What is the prey’s food source?
6. The number of deer is decreasing rapidly because the wolves and
the fellow predators are eating them. Simple predator-prey theory
describes a relationship between a predator and prey; but what is
the relationship between the wolves and the fellow predators?
7. More recent research suggests that deer population numbers
fluctuate even when wolves are excluded from the environment.
What might be responsible for this “natural” fluctuation? What are
the implications of this phenomenon, in terms of population
numbers for wolves and deer over time even when the
populations do not interact?
8. Would you expect to see the same type of “natural” fluctuations in
the wolf population in the absence of deer prey? Explain.