Ch 54 AP Bio Study Guide

Part A Which of the following statements is in accordance with F. E. Clements' view that species in a community function as an integrated unit? A. A community at a particular site has only one stable equilibrium. B. Species composition is determined by island size and distance from the mainland. C. Most communities are not at equilibrium. D. Most communities are chance assemblages of species found together because they have similar abiotic requirements. E. Food chains are not isolated units but are linked together in food webs.

A. A community at a particular site has only one stable equilibrium. (According to Clements' view, biotic interactions cause the species in a community to function as an integrated unit--in effect, a superorganism--with only one stable equilibrium.)

Food chains are sometimes short because A. most of the energy in a trophic level is lost as it passes to the next higher level. B. local extinction of a species causes extinction of the other species in its food chain. C. most producers are inedible. D. predator species tend to be less diverse and less abundant than prey species. E. only a single species of herbivore feeds on each plant species.

A. most of the energy in a trophic level is lost as it passes to the next higher level.

Cellulose-digesting microorganisms live in the guts of termites and ruminant mammals. The microorganisms have a home and food, and their hosts gain more nutrition from their meals. This relationship is an example of _____. A. mutualism B. predation C. commensalism D. parasitism E. herbivory

A. mutualism The cellulose-digesting microorganisms have a home and place to live; the hosts get nutrients from the microorganism's breakdown of cellulose.

According to MacArthur and Wilson's hypothesis of island biogeography, species immigration and extinction rates on a particular island correlate to _____. A. the island's size and distance from the mainland B. how the island formed C. when the island formed D. the number of other islands in the archipelago E. the island's stage of ecological succession

A. the island's size and distance from the mainland

The principle of competitive exclusion states that A. two species that have exactly the same niche cannot coexist in a community. B. two species cannot coexist in the same habitat. C. competition between two species always causes extinction or emigration of one species. D. competition in a population promotes survival of the best-adapted individuals. E. two species will stop reproducing until one species leaves the habitat.

A. two species that have exactly the same niche cannot coexist in a community.

Keystone species are those species _____. A. whose absence would cause major disruption in a community B. that have the most biomass in the community C. with the largest number of individuals in a community D. that provide important foods and medicines E. that live primarily on or under rocks and stones

A. whose absence would cause major disruption in a community (A keystone species makes an unusually strong impact on community structure.)

Of the choices below, which best describes the effect predation has on the predator/prey organisms involved in the relationship? A. benefit ... no effect B. benefit ... harmed C. harmed ... harmed D. no effect ... benefit E. benefit ... benefit

B. benefit ... harmed The predator eats (a benefit), and the prey is eaten (a harm).

In an ecosystem, phytoplankton are _____. A. secondary consumers B. producers C. primary consumers D. detritivores E. tertiary consumers

B. producers (Autotrophs, such as phytoplankton, are producers.)

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that A. diversity increases as evapotranspiration decreases. B. tropical regions generally have more available water and higher levels of solar radiation. C. higher temperatures cause more rapid speciation. D. tropical communities are younger. E. tropical regions have very high rates of immigration and very low rates of extinction.

B. tropical regions generally have more available water and higher levels of solar radiation.

Which of the following could qualify as a top-down control on a grassland community? A. limitation of plant biomass by rainfall amount B. influence of soil nutrients on the abundance of grasses versus wildflowers C. effect of grazing intensity by bison on plant species diversity D. influence of temperature on competition among plants E. effect of humidity on plant growth rates

C. effect of grazing intensity by bison on plant species diversity

An organism's "trophic level" refers to _____. A. the rate at which it uses energy B. where it lives C. its food source D. whether it is early or late in ecological succession E. the intensity of its competition with other species

C. its food source (An organism's trophic level is determined by what it eats.)

According to the equilibrium model of island biogeography, species richness would be greatest on an island that is A. small and close to a mainland. B. environmentally homogeneous. C. large and close to a mainland. D. small and remote. E. large and remote.

C. large and close to a mainland.

Keystone predators can maintain species diversity in a community if they A. prey only on the least abundant species in the community. B. allow immigration of other predators. C. prey on the community's dominant species. D. competitively exclude other predators. E. reduce the number of disruptions in the community.

C. prey on the community's dominant species.

A cow eating grass is an example of a _____. A. tertiary consumer B. producer C. primary consumer D. secondary consumer E. detritivore

C. primary consumer (By feeding on a producer, the cow is acting as a primary consumer.)

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____. A. producer B. primary consumer C. tertiary consumer D. detritivore E. secondary consumer

C. tertiary consumer (The shark that ate the human that ate the cow that ate the grass is the tertiary consumer.)

The feeding relationships among the species in a community determine the community's A. secondary succession. B. ecological niche. C. trophic structure. D. species richness. E. species-area curve.

C. trophic structure.

Which of the following best illustrates ecological succession? A. A mouse eats seeds, and an owl eats the mouse. B. Introduced pheasants increase, and native quail populations disappear. C. Overgrazing causes a nutrient loss from soil. D. Grass grows on a sand dune, is replaced by shrubs, and then by trees. E. Decomposition in soil releases nitrogen that plants can use.

D. Grass grows on a sand dune, is replaced by shrubs, and then by trees. (This illustrates the replacement of species as a community matures.)

Caribbean coral reef communities have been strongly influenced by an unknown pathogen that causes white-band disease. How can the effect of white-band disease best be described? A. commensalism B. mutualism C. the removal of a keystone species D. a cascade event that shifts the entire makeup of the community E. Batesian mimicry

D. a cascade event that shifts the entire makeup of the community (The removal of the corals shifts the food supply within the reef, resulting in a completely different species composition.)

According to the principle of competitive exclusion, two species cannot continue to occupy the same _____. A. range B. environmental habitat C. territory D. ecological niche E. biome

D. ecological niche

When a human eats a steak, the human is acting as a _____. A. primary consumer B. producer C. detritivore D. secondary consumer E. tertiary consumer

D. secondary consumer (By feeding on a primary consumer, the human is acting as a secondary consumer.)

The term used to describe a harmless organism resembling a harmful one is _____. A. cryptic coloration B. aposematic coloration C. warning coloration D. Müllerian mimicry E. Batesian mimicry

E. Batesian mimicry In Batesian mimicry, a palatable or harmless species mimics an unpalatable or harmful model.

Which of these is a starting point for primary succession? A. an abandoned city B. none of these is a starting point for primary succession C. abandoned farmland D. a neglected yard E. a surface exposed by a retreating glacier

E. a surface exposed by a retreating glacier Such a surface lacks any life and is thus a starting point for primary succession. An abandoned city is a starting point for secondary succession.

An earthworm that feeds on the remains of plants and animals is acting as a _____. A. producer B. secondary consumer C. primary consumer D. tertiary consumer E. detritivore

E. detritivore (The earthworm is feeding on the remains of dead organisms.)

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by A. frequent massive disturbance. B. human intervention to eliminate disturbance. C. stable conditions with no disturbance. D. intensive disturbance by humans. E. moderate levels of disturbance.

E. moderate levels of disturbance.

Which of the following may result from resource partitioning? Select all that apply. [] A population may have a smaller realized niche when it coexists with a competitor. [] Competing species may partition time, feeding at different times of day. [] A population's fundamental niche may be smaller than its realized niche.

[] A population may have a smaller realized niche when it coexists with a competitor. AND [] Competing species may partition time, feeding at different times of day.

Select the correct statement(s) about a terrestrial food chain. Select all that apply. [] About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level. [] Energy is transferred from decomposers to plants to herbivores to carnivores. [] The total biomass of the top trophic level is greatest because the top consumers are large.

[] About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level.

Gray wolves, once the top predators in Yellowstone National Park, were hunted to extinction there in 1926. In 1995, 15 wolves were brought to Yellowstone from Alberta. The wolf population has now grown to 300. The forest community in Yellowstone National Park can be described by a top-down model of community organization. Wolves hunt and eat elk. Elk are herbivores that prefer riparian vegetation (plants growing next to streams and lakes). Ravens, bears, and eagles feed on elk carcasses. How would you expect the return of the wolves to Yellowstone to affect the other species there? Select all that apply. [] Bear populations would decline. [] Riparian vegetation would decline. [] Elk populations would decline.

[] Elk populations would decline.

What is a likely outcome of a moderate disturbance, such as a severe thunderstorm? Select all that apply. [] Reduced species diversity within a community [] Patches of different habitats within the landscape [] Loss of an equilibrium state of balance, leading to a less healthy community

[] Patches of different habitats within the landscape

Select the correct statement(s) about the transfer of food energy up the trophic levels from its source in autotrophs. Select all that apply. [] Few plants have adaptations to reduce feeding by herbivores. [] An organism feeds at only one trophic level. [] The length of a food chain is limited by the inefficiency of energy transfer along the chain.

[] The length of a food chain is limited by the inefficiency of energy transfer along the chain.