AP Environmental Science : Ecosystems and Biology

Study concepts, example questions & explanations for AP Environmental Science

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Example Questions

Example Question #2 : Natural Selection

What two factors determine biological fitness?

Possible Answers:

Survival and reproductive rate

Allele frequency and genetic diversity 

Survival and size

Genetic diversity and population size

Genetic diversity and age of first reproduction

Correct answer:

Survival and reproductive rate

Explanation:

The correct response is survival and reproductive rate. These are the two factors that are used to determine the fitness of an individual. There are other variables that can impact survival and reproduction rate, but these are the two foundational factors that impact fitness.

Fitness = Rate of Survival times Rate of Reproduction

Thus, if an individual lives to be 100 years old but has 0 children, then their overall fitness is 0. (Fitness = 100 x 0 = 0)

Example Question #1 : Natural Selection

What is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment?

Possible Answers:

Genotype

Nomenclature

Haploid

Phenotype

Correct answer:

Phenotype

Explanation:

The phenotype is described as the observable characteristics of an organism. Natural selection is based on survival of the fittest due to differences in phenotype. This is not to be confused with genotype, which is the genetic (DNA sequence) of a trait.

Example Question #14 : Ecological Change

__________ is responsible for the idea of natural selection. 

Possible Answers:

Ronald Fisher

Jean-Baptiste Lamarck

Charles Darwin

Empedocles

Correct answer:

Charles Darwin

Explanation:

The modern theory that is natural selection is from the studies of Charles Darwin. His theory of natural selection was an explanation for the adaptation of species. He further explored his ideas in his book, The Origin of Species. 

Example Question #2 : Natural Selection

An organism's fitness, as it applies in natural selection, involves __________.

Possible Answers:

the number of their offspring that reproduce themselves

the efficiency with which they hunt

the number of mates with whom they reproduce

their ability to chase prey for extended periods of time

Correct answer:

the number of their offspring that reproduce themselves

Explanation:

In natural selection, the term fitness means how successful the organism is in reproducing. If an organism has a large amount of offspring, but lives half as long as its similar organisms, it is still more successful because its genes will be apart of more offspring, who will reproduce themselves.

Example Question #91 : Ecosystems And Biology

In a particular habitat, Species A competes with Species B for food resources. Which type of competition is this?

Possible Answers:

Intraspecific interference competition

Interspecific interference competition

Intraspecific exploitation competition

Interspecific exploitation competition

Correct answer:

Interspecific exploitation competition

Explanation:

Interspecific competition is that which occurs between two different species. Exploitation competition involves the two groups of organisms competing for a limited resource, which may or may not involve direct contact between the species. Interference competition involves direct contact between organisms. 

Example Question #21 : Ecological Change

What is the term for the formation of new species through the course of evolution?

Possible Answers:

Allele frequency 

Fecundity selection

Speciation

Bottleneck effect

Correct answer:

Speciation

Explanation:

Speciation is the term for formation of new species throughout the process of evolution. Isolated groups might split off from a species to become an entirely different species. This could be caused from changes in selection pressures, mutations, or genetic drift. 

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

A plant community becoming simplified with fewer species and less biomass

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

An ecosystem diversifying, supporting more species and increases in biomass

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 #1 : Ecological Succession

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

Possible Answers:

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

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

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

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

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 #1 : Ecological Succession

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

Possible Answers:

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.

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

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. 

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

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 #1 : Ecological Succession

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

Possible Answers:

Wind-carried soil particles and nutrients

Soil nutrients deposited by a nearby river

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

Pre-existing nitrogen-fixing plant communities

Feces from wildlife populations that occupy the region

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.

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