Oh Deer

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Name_______________________
Date______________
Partner(s)___________________________
Ms. Pearson
Honors Biology
100 points
Oh Deer!
How does a population of prey affect a population of predators?
Introduction
Animals spend much of their time looking for and consuming food. Some eat
plants (herbivores), some eat meat (carnivores), and some eat both (omnivores).
Many carnivores obtain their meat by actively hunting other animals. The hunters
are known as predators and the hunted animals are known as prey. In this lab, you
will do a simulation of a predator—prey relationship, with wolves as predators and
deer as prey. This is a simulation that shows the relationship between deer and
wolves. By following the directions, you will determine how the population of one
species can affect the other species. You will work in partners to collect your data,
but you are individually responsible for your graph and questions.
Directions:
1. Place 3 deer(prey) on your table.
2. Toss 1 wolf ( predator) onto the table and attempt to make the card touch as many prey as
possible. In order to survive, the predator must capture at least 3 prey. It will be impossible
for your predator to survive at this point.
.
3. Remove any deer captured and record your data for the 1st generation.
4. The deer population doubles each generation. Count how many deer you have left on your
table, double that number and add deer cards to the table.{ For example if you still have 3 deer ,
you will add 6 deer to the forest( 3x2) } Record the number in the data table under the 2nd
generation “number of deer staring”.
5. Your wolf/ predator died during the first round, but that’s okay, a new predator moves in for
the second round. Put a 1 in the “number of predators starting” for generation 2 to represent the
new arrival. Repeat the tossing procedure and record your data for the second generation.
6. Again, number of deer/ prey doubles, if your wolf/predator didn’t “capture” 3 prey, it died.
But a new one moves in for the next round. Keep going, adding to the number of prey each
round.
7. Eventually your predator will be able to capture enough prey to survive. Guess what happens?
The number of predators double. Add to your predator population by adding predator cards. Now
when you toss your predators, you will be tossing more than one. Don’t forget to remove any
“captured” prey.
8. Continue to record the data through 25 generations.
9. Construct a graph. On the X-axis, put generations 1 through 25, on the Y-axis you will have
the population numbers for each generation (number of predators, number of prey). Use one line
for the predator and one line for the prey to graph the data. It is a good idea to do one at a time.
Your should graph using different colors.
.
Data Table( 20 points)
Deer
Generation
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
# of Deer
Starting
(Prey)
# of
Wolves
Starting
(Predator)
# of Wolves
Surviving
# of Deer
Caught
# of Deer
Remaining
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Graph (30 points)
Post -Activity Questions (50 points)
1. Which population always increased first? Why?
2.
If you removed the wolves from this community, what would your graph look like?
3.
How long did a cycle of increase and decrease take for deer? For wolves? ( a cycle is the
number of years between each peak)
4.
Which population was almost always in greater numbers? Why?
5.
If a student failed to include a legend, what are three ways you could tell the difference
between the mountain lion line and the rabbit line?
6.
If this simulation were to continue for 25 more generations, what would you predict for
the size of the deer and wolf populations?
7.
What other factors, besides the number deer and wolves , would influence the shape of
the graph in a forest?
8.
The predator/prey relationship we have modeled in class is a simple relationship because
it involves only 2 animals, the deer and the wolf. From your vast storehouse of knowledge you
know that other animals prey on deer. How might another predator affect out deer and wolf
distribution?
9.
If the reproduction rate of the predator increased how would this affect the shape of the
graph over time?
10. This predator/prey graph lacks a lag time between predator population and prey population
peaks. Why do populations lag in a real predator prey graph?
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