AP Environmental Science : Ecological Succession

Study concepts, example questions & explanations for AP Environmental Science

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1

Example Question #1 : Ecological Succession

Which of the following is an example of primary succession?

Possible Answers:

A succession of larger plants (trees, shrubs, etc.) following the establishment of pioneer species

A transition from one ecosystem type to another

An ecosystem diversifying, supporting more species and increases in biomass

A plant community becoming simplified with fewer species and less biomass

Plant communities are established in a lifeless environment, usually devoid of soil

Correct answer:

Plant communities are established in a lifeless environment, usually devoid of soil

Explanation:

Primary succession commonly occurs after a volcanic eruption or a glacier recedes, because these areas have been stripped of organic matter. Primary succession is the process by which pioneer species colonize an area otherwise uninhabitable for plant life and generate nitrogen for other plant communities.

Example Question #2 : Ecological Succession

Which of the following provides the most accurate example of primary succession? 

Possible Answers:

Native grass communities forming after a wildfire burned through a meadow/woodland ecosystem

Coral reef and aquatic wildlife communities that have re-established themselves in regions of the South Pacific that were evacuated following the nuclear tests conducted by the U.S. military

Lichens re-establish themselves on rocks and shallow soil beds following a tundra fire

Seedlings establishing themselves in a heavily logged area where the seed-tree cutting method was employed

Lichen and grass communities establishing themselves on a recently-formed island, resulting from an uplift in the ocean bedrock

Correct answer:

Lichen and grass communities establishing themselves on a recently-formed island, resulting from an uplift in the ocean bedrock

Explanation:

Primary succession is characterized by plants establishing themselves in areas that were initially devoid of soil (usually bedrock). Grasses establishing themselves on a newly-formed island that is mostly bedrock is the best fit for this definition.

Example Question #3 : Ecological Succession

Which of the following is the most accurate example of secondary succession?

Possible Answers:

Following the Dust Bowl of the 1930's, prairie grasses reestablished themselves in areas had lost most of their fertile soil to wind erosion. 

A forest fire burns down crowded understory grasses and shrubs as well as some ponderosa pine stands in the Black Hills of South Dakota.

In 1962, a volcanic eruption off the coast of Iceland resulted in a formation of a new island "Surtsey" from ocean bedrock. 

Lichens and small spruce trees have established themselves in regions of Alaska where glaciers once existed but have since receded.

Twenty years after the Mount St. Helens eruption, small trees and grasses have begun to regrow near the top of the peak, where the eruption occurred.

Correct answer:

A forest fire burns down crowded understory grasses and shrubs as well as some ponderosa pine stands in the Black Hills of South Dakota.

Explanation:

Primary succession is characterized by a total loss of biomass and soil from the ecosystem or a beginning lack thereof. Land that has been covered by a glacier or under the seabed will be devoid of soil, much like the exposed bedrock seen after the Dust Bowl or the Mount St. Helens eruption. By contrast, a forest fire can typically be characterized as secondary succession because the soil remains intact and the ecosystem can typically recover much quicker because of that fact.

Example Question #4 : Ecological Succession

Which of the following would NOT contribute significantly to primary succession?

Possible Answers:

The time-consuming process of weathering the bedrock into smaller particles

Soil nutrients deposited by a nearby river

Feces from wildlife populations that occupy the region

Wind-carried soil particles and nutrients

Pre-existing nitrogen-fixing plant communities

Correct answer:

Pre-existing nitrogen-fixing plant communities

Explanation:

Primary succession is characterized by pioneer species establishing themselves in areas that are predominantly bedrock and devoid of organic material. The formation of organic material in these areas typically occurs with the accumulation of wind-carried soil erosion, nutrients deposited by flowing bodies of water, and erosion of bedrock. Wildlife populations are also a significant contributor of soil nutrients, with feces being rich in both nitrogen and phosphorus. In contrast, pre-existing nitrogen-fixing plants (or any pre-existing plant communities) are uncommon to nonexistent in an area with no established soil system.

Example Question #4 : 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:

Evolution

Natural selection

Succession

Adaptation

Mutation

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 #3 : Ecological Succession

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

Possible Answers:

Trees

Moss

Lichen

Grass

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 #5 : 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:

Primary succession

None of these

Climax succession

Secondary succession

Pioneering succesion

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 #8 : 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:

Grasses

Bears

Shrubs

Gorillas

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 #7 : 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:

Primary succession

Tertiary succession

Quaternary succession

Secondary 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 #10 : 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. 

← Previous 1
Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: