Aim for FiveEnvironmental Science

Analyze and interpret quantitative data

Deer on an island

  • Units 1 and 3
  • 10 points
  • About 23 minutes

You can use a calculator on this question, just like on exam day.

You read values and trends from a data table or described graph, explain what the data show about an environmental problem, and propose and justify a solution. On the exam: Question 2 of 3 in the 70-minute free-response section (Section II is 40% of the exam score).

The question and its sources

In Year 0, twenty deer were brought to a forested island with no deer and no large predators. Hunting is not allowed on the island. Biologists counted the deer and measured the percentage of the ground covered by shrubs, the deer's main winter food, every few years.

Table 1: Deer population and shrub cover on the island

YearNumber of deerShrub cover (%)
02070
46070
818066
1252052
1486035
1664022
1830018
2238024
2641030
3040031

Source: Hypothetical data

Suggested time: 23 minutes

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Part (a)

1 point

Identify the type of population growth shown from Year 0 to Year 12.

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Part (b)

1 point

Using Table 1, estimate the carrying capacity of the island for deer at the end of the study.

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Part (c)

1 point

Describe what happened to the deer population between Year 12 and Year 18.

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Part (d)

1 point

Use the data in Table 1 to explain why the deer population declined after Year 14.

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Part (e)

1 point

Identify one density-dependent factor that limits the deer population on the island.

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Part (f)

1 point

Identify one density-independent factor that could reduce the deer population on the island.

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Part (g)

1 point

Deer are considered a K-selected species. Describe one characteristic of deer that is typical of K-selected species.

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Part (h)

1 point

The biologists propose bringing wolves to the island. Explain how wolves could affect the island's shrubs.

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Part (i)

1 point

Propose one realistic way, other than bringing in wolves, to keep the deer population from overshooting the carrying capacity again.

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Part (j)

1 point

Use the data in Table 1 to justify the solution you proposed in part (i).

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