Task: Investigating Populations
An island population of deer has no predators and the island is too
remote for hunters. Is it better to let nature take its course with the
deer population or should predators be introduced onto the island?
You are a wildlife manager working to restore the population of an
endangered species of deer. Currently,
small and your task is to find the best
situation for the population to grow
into a healthy herd. Analyze the two
sets of data.
the herd is
habitat and
and develop
scenarios and
Scenario A: A herd lives in a 100 square mile range in the Bitterroot mountains of Montana. It has been continually
inhabited by this species for centuries. Human settlers eliminated wolves (one of the deer’s predators) over 100 years
ago although other habitat changes caused by human development have continued to keep the deer’s populations low.
Now the habitat is improving and the deer population is growing slowly but steadily. Some wildlife managers have
reintroduced several families of wolves to the region.
Graph the deer population on the graph paper provided.
Year
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
Popn
2000
2100
2060
2010
1980
2000
1840
1710
1590
1440
1400
1290
1300
1260
1310
1360
1290
1330
Scenario B: The deer herd is moved and reintroduced to a new, more favourable habitat. The new area is a deserted
island in the arctic region. There is a lot of food (no animal has filled the deer’s niche for many years) and there are no
natural predators. The island has 41 square miles of good habitat for the population. The graph below illustrates what
happened to a population of isolated deer on a deserted island in the Arctic in the early 1900s.
ANSWER THE QUESTIONS BELOW. ANSWERS SHOULD BE IN FULL SENTENCES (EXCEPT 1). USE PROPER SCIENTIFIC
TERMINOLOGY FROM THE UNIT.
THINKING/INQUIRY
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15
APPLICATION
COMMUNICATION
LEVEL
LEVEL
Thinking/Inquiry – Answers to questions
- Answers are complete and correct.
Communication – Graph contains the following:
- Relevant (and specific title)
- Labelled axes (with units)
- Correctly plotted points
- Accurate scale
- Pencil
- Smooth line connecting points
Application
- Position is clearly stated
- States 2 strong points to support position.
- Provides evidence from both graphs to support points.
0 1 2 3 4 5 6 7 8 9 10
0 1 2 3 4 5 6 7 8 9 10
1. Describe the growth pattern in scenario A. Use dates to clearly describe increases, decreases, rapid growth and
slow growth, fluctuation. (3 marks)
2. When do you think the wolves were introduced? Use data from Graph A to support your answer. Provide a
reason for your answer. (3 marks)
3. Graph B represents Scenario B. If there were no predators, explain why couldn’t the deer population survive?
(2 marks)
4. a) Define carrying capacity from your notes. Which graph shows the deer reaching a stable population? Support
your answer with evidence from the graph (dates and numbers). (3 marks)
b) Estimate the carrying capacity for the deer. (1 mark)
5.
___________________________
Humans act as predators when we hunt and fish. How are our actions different from natural predators of an
ecosystem? Discuss both humans and natural predators. (3 marks)
6. As a wildlife manager, what is your recommendation to save the deer? Would the deer be better off, worse off,
or about the same with the wolves? Defend your answer with at least 2 strong points and use supporting details
from the graphs.
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