AP Environmental Science : Ecosystems and Biology

Study concepts, example questions & explanations for AP Environmental Science

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Example Questions

Example Question #1 : Ecological Succession

Which of the following is a structural change in a community and its nonliving environment over time that alters the ecosystem?

Possible Answers:

Mutation

Succession

Evolution

Natural selection

Adaptation

Correct answer:

Succession

Explanation:

Succession is a structural change in a community and its nonliving environment over time. Community changes alter the ecosystem in ways that favor competitors, and species replace one another in a somewhat predictable manner until a stable community is reached. Examples are the changes that occur after volcanos erupt and forest fires. Adaptation is a characteristic of an organism that helps it survive and reproduce in a particular environment. The differential survival and reproduction on the basis of genetic differences among individuals is termed natural selection. Evolution is any change in the proportions of different genotpyes in a population from one generation to the next. Mutation is a change in the base sequence of DNA in a gene that is usually significant enough to alter the appearance or function of the organism. 

Example Question #1 : Ecological Succession

Which of the following are least likely to be present during primary succession?

Possible Answers:

Trees

Grass

Lichen

Moss

Correct answer:

Trees

Explanation:

Primary succession begins with no soil. Eventually, lichens and mosses grow and die, which creates some soil. Small plants such as grasses and some ferns use this soil and grow. It would be very unlikely for a tree to grow in this environment.

Example Question #2 : Ecological Succession

Ecosystems recover from disturbances in unique ways. A landscape ecologist observes in area right after a volcanic eruption. There is lava and dust across the landscape, and all vegetation has been removed. What is this ecosystem experiencing?

Possible Answers:

Climax succession

Secondary succession

Pioneering succesion

None of these

Primary succession

Correct answer:

Primary succession

Explanation:

The correct response is primary succession. This represents the initial growth following a disturbance, such as a volcanic eruption. While pioneering succession involves the colonization of a location that has been affected by ecological damage, primary succession is a better answer since it refers specifically to vegetation colonizing a location in which soil is absent (such as after a volcanic eruption). Climax succession is not a term used to describe species succession over time, rather, a climax community is one that, over time, has reached a steady state.

Example Question #1 : Ecological Succession

After an event such as a fire or a tree fall in a forest, early successional species are the first to reappear. Which is an example of early successional species?

Possible Answers:

Bears

Gorillas

Shrubs

Grasses

Correct answer:

Grasses

Explanation:

Grasses are also early successional species because they reproduce quickly and require minimal diversity of resources to survive. Their quick reproduction and growth also categorizes them as R-selected species.

Example Question #2 : Ecological Succession

A glacier has just receded across the landscape. As the glacier retreated, it completely decimated all standing vegetation. The landscape recovers quickly because there are plenty of seeds left in the seed bank. What is this an example of?

Possible Answers:

Tertiary succession

Secondary succession

Primary succession

Quaternary succession

Correct answer:

Secondary succession

Explanation:

The correct response is secondary succession. This process occurs following some disturbance when the seedbank is still intact. For example, after an earthquake or fire all the vegetation is removed but there are still seeds in the ground. This would be an example of secondary succession because the vegetation can still recover. This is different from primary succession - primary succession occurs when there is no prior vegetation on the landscape and there is no seedbank. Tertiary and quaternary succession are made up terms.

Example Question #2 : Ecological Succession

What is the process by which ecosystems change gradually overtime? 

Possible Answers:

Ecological succession

Climax community 

Pre-existing disturbance

Greenhouse effect 

Correct answer:

Ecological succession

Explanation:

Ecological succession is the change of the structure of an environment overtime. The environment can be changed due to a sudden disruption or small changes overtime. These changes can take place over a few decades or millions of years. 

Example Question #101 : Ecosystems And Biology

Which of the following is an accurate example of primary ecological succession?

Possible Answers:

A woodland ecosystem has been overbrowsed by moose that quite enjoy low-lying willow branches and seedlings, resulting in a depletion of young willow trees. Deer soon replace moose in the woodland to graze on the abundant grasses and sedges.

River sediments are deposited along a waterfront consisting of barren rock, resulting in the establishment of moss and grass communities.

A wildfire burns through the underbrush of a hardwood forest, freeing up available sunlight for new understory brush.

A windstorm displaces nutrient-rich topsoil that has been heavily tilled, resulting in diminished fertility and inability for plant communities to establish themselves.

Boreal forests throughout Alaska and Canada are undergoing a transition where short-lived conifer stands are slowly replaced by deciduous hardwood stands, which are characteristic of a more mature forest.

Correct answer:

River sediments are deposited along a waterfront consisting of barren rock, resulting in the establishment of moss and grass communities.

Explanation:

Primary succession is, by definition, the establishment of living communities in areas where life had not previously existed. A waterfront that is barren rock does not initially have the potential to support life until mineral and soil deposits allow new plant communities to establish themselves. The other answers are not correct because plant communities already exist in these examples, which is not characteristic of primary succession. 

Example Question #102 : Ecosystems And Biology

Which of the following organisms would be most likely to be found in an ecosystem undergoing primary succession?

Possible Answers:

Black Oak

Lichen

Blueberry

Atlantic Cedar

White Pine

Correct answer:

Lichen

Explanation:

Lichens are able to survive on bare rocks, with very few nutrients available. As a result, they are one of the first organisms to colonize an area of primary succession, where they usually break down rocks over time to form the base of soil in the new habitat.

Example Question #101 : Ecosystems And Biology

Which of the following is not a risk management strategy?

Possible Answers:

sectarian method

market-based method

rational method

hierarchical method

conservative method

Correct answer:

conservative method

Explanation:

Market-based, hierarchical, sectarian, and rational methods are all risk management strategies. Conservative method is not a risk management strategy.

Example Question #1 : Human Impact On Ecological Change

Clear-cutting has become industry practice for harvesting timber; however, some forests evolved to regenerate after forest fires and have adapted to massive clearings of habitat. Which of the following is a problem that these forests might encounter when faced with clear-cutting?

Possible Answers:

Only pioneer species will grow after a clear-cut. 

The soil is exhausted from a clear-cut, whereas it is replenished in a forest fire, making succession more difficult. 

Many fire-adapted conifers have seeds that will not germinate unless exposed to high temperatures, which does not occur in clear-cutting. 

Small mammals that feed on pine cones will not be killed of in a clear-cut as opposed to a forest fire, making regeneration of stands more difficult. 

Even forest fires leave some live stands to produce seeds for future stands. 

Correct answer:

Many fire-adapted conifers have seeds that will not germinate unless exposed to high temperatures, which does not occur in clear-cutting. 

Explanation:

Many Rocky Mountain and Western conifer species are adapted to germinate only after being exposed to temperatures typical of a wildfire. Pioneer species and shrubs typically have no problem generating after a clear-cut, but often foresters have to plant pine saplings in a clear-cut area, because remaining seeds will not germinate.

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