Chapter 46 Flashcards

Approximately how many kilograms (kg) of carnivore (secondary consumer) biomass can be supported by a field plot containing 1000 kg of plant material?

1. 1000
2. 100
3. 10
4. 1

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to _____.

1. expand its realized niche
2. decline in abundance
3. become the target of specialized parasites
4. change its fundamental niche

Which of the following could qualify as a top-down control on a grassland community?

1. effect of grazing intensity by bison on plant species diversity
2. influence of soil nutrients on the abundance of grasses versus wildflowers
3. limitation of plant biomass by rainfall amount
4. influence of temperature on competition among plants

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?

1. parasitism
2. commensalism
3. consumption
4. mutualism

Zoonotic disease _____.

1. can only be transferred from animals to humans by means of an intermediate host
2. can only be spread from animals to humans through direct contact
3. is caused by suborganismal pathogens such as viruses, viroids, and prions only
4. is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector

Why do moderate levels of disturbance result in an increase in community diversity?

1. Less-competitive species evolve strategies to compete with dominant species.
2. Competitively dominant species infrequently exclude less competitive species after a moderate disturbance.
3. The resulting uniform habitat supports stability, which in turn supports diversity.
4. Habitats are opened up for less competitive species.

According to the equilibrium model of island biogeography, species richness would be greatest on an island that is _____.

1. large and close to a mainland
2. small and close to a mainland
3. large and remote
4. small and remote

Which island would likely have the lowest extinction rate?

1. A
2. C
3. D
4. E

Bouchard and Brooks studied the effect of insect flight on dispersal and speciation in rain forest insects. They sampled all of the insects in the study area and found that 60 insect species are flightless and 19 are macropterous (able to fly). What can you conclude so far about this study?

1. Flightless insects are more numerous in the study area.
2. Flightless insects are better suited for the tropics.
3. Flightless insects have a greater dispersal potential from this study area.
4. Flightless insects have a higher richness in the study area.

Which of the following is an example of cryptic coloration?

1. markings of a viceroy butterfly's wings
2. bands on a coral snake
3. brown or gray color of tree bark
4. a "walking stick" insect that resembles a twig

Which of the following is an example of Batesian mimicry?

1. a butterfly that resembles a leaf
2. a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
3. a nonvenomous snake that looks like a venomous snake
4. a fawn with fur coloring that camouflages it in the forest environment

Which of the following is an example of aposematic coloration?

1. a katydid whose wings look like a dead leaf
2. the brightly colored patterns of poison dart frogs
3. green color of a plant
4. eye color in humans

Recall that Clements's view of biological communities is that of a highly predictable and interrelated structure, while Gleason's view of biological communities is that individual species operate independently. If we set up many identical sterilized ponds in the same area and allowed them to be colonized, what should we predict if we wished to test Gleason's hypothesis?

1. Identical plankton communities will develop in all ponds.
2. Similar plankton communities will develop in all ponds.
3. Limited plankton communities will develop in all ponds.
4. Different plankton communities will develop in all ponds.

Which of the following would be most significant in understanding the structure of an ecological community?

1. only I, II, and III
2. only II and IV
3. only I and III
4. I, II, III, and IV

In terms of community ecology, why are pathogens often more virulent now than in the past?

1. Medicines for treating pathogenic disease are in short supply.
2. Human activities are transporting pathogens into new habitats (or communities) at an unprecedented rate.
3. More new pathogens have recently evolved.
4. Host organisms have become more susceptible because of weakened immune systems.

What is the main advantage of controlled burnings of forested areas? Controlled burnings _____.

1. allow new species to form
2. prevent the overgrowth of the underbrush
3. clear forested areas for farmland
4. eliminate the possibility of forest fires

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that _____.

1. tropical regions generally have more available water and higher levels of solar radiation
2. tropical regions have very high rates of immigration and very low rates of extinction
3. tropical communities are younger
4. higher temperatures cause more rapid speciation

What interactions exist between a lion pride and a hyena pack?

1. +/+
2. +/-
3. o/o
4. -/-

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by _____.

1. moderate levels of disturbance
2. stable conditions with no disturbance
3. intensive disturbance by humans
4. frequent massive disturbance

What interactions exist between cellulose-digesting organisms in the gut of a termite and the termite?

1. +/+
2. +/o
3. +/-
4. o/o

Which of the following statements is consistent with the principle of competitive exclusion?

1. The random distribution of one competing species will have a positive impact on the population growth of the other competing species.
2. Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
3. Natural selection tends to increase competition between related species.
4. Two species with the same fundamental niche will exclude other competing species.

Which of the following best describes the consequences of white-band disease in Caribbean coral reefs?

1. Key habitat for lobsters, snappers, and other reef fishes improves.
2. Algal species take over and the overall reef diversity increases due to increases in primary productivity.
3. Staghorn coral is decimated by the pathogen, and Elkhorn coral takes its place.
4. Algal species take the place of the dead coral, and the fish community is dominated by herbivores.

Which island would likely have the greatest species diversity?

1. A
2. C
3. D
4. E

Treehoppers (a type of insect) produce honeydew, which ants use for food. Treehoppers have a major predator, the jumping spider. Researchers hypothesized that the ants would protect the treehoppers from the spiders. In an experiment, researchers followed study plots with ants removed from the system and compared them to a control plot. In the figure above, what can you conclude?

1. Ants eat the honeydew produced by treehoppers
2. Ants do somehow protect the treehoppers from spiders.
3. Ants reduce the numbers of treehoppers.
4. No specific conclusions can be drawn from this figure.

What conclusion can you draw from the figure above?

1. Mussels can sense the presence of crabs only visually.
2. Crabs hunt for mussels by focusing on the chemicals they emit into the water.
3. Mussels are increasing their shell thickness in response to water current.
4. Without direct contact, mussels can sense the presence of crabs.

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities?

1. Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude.
2. More competitive dominant species have evolved in temperate and polar communities.
3. There are fewer parasites to negatively affect the health of tropical communities.
4. Tropical communities are generally older than temperate and polar communities.

Why is a pathogen generally more virulent in a new habitat?

1. Pathogens evolve more efficient forms of reproduction in new environments.
2. New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts.
3. Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.
4. Intermediate host species are more motile and transport pathogens to new areas.

Connell conducted this experiment to learn more about _____.

1. habitat preference in two different species of barnacles
2. how sea-level changes affect barnacle distribution
3. character displacement in the color of barnacles
4. competitive exclusion and distribution of barnacle species

Which of the following studies would a community ecologist undertake to learn about competitive interactions?

1. only I and III
2. I, II, and III
3. only II and III
4. only I and II

In some circumstances, grasses benefit from being grazed. Which of the following terms would best describe such a plant-herbivore interaction?

1. parasitism
2. predation
3. mutualism
4. commensalism

According to bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact its prey (P) population, but not vice versa?

1. P ← C → P
2. C ↔ P
3. P ← C
4. P → C

Resource partitioning would be most likely to occur between _____.

1. sympatric populations of a flowering plant and its specialized insect pollinator
2. sympatric populations of species with similar ecological niches
3. allopatric populations of the same animal species
4. allopatric populations of species with similar ecological niches

During a one-year study, researchers found no difference in treehopper populations in any of their control and experimental groups. What could they measure during the second year to gain information about why this might have occurred?

1. Measure the relative abundance of jumping spiders.
2. Measure the number of ant females.
3. Measure the relative sizes of the treehoppers.
4. Measure the relative sizes of different ant species.

Which letter represents an organism that could be a producer?

1. A
2. B
3. D
4. E

There are more species in tropical areas than in places more distant from the equator. This is probably a result of _____.

1. more intense annual solar radiation
2. more frequent ecological disturbances
3. fewer agents of disease
4. fewer predators

Which of the following is an example of a commensalism?

1. bacteria fixing nitrogen in plants
2. rancher ants that protect aphids in exchange for sugar-rich honeydew
3. cattle egrets eating insects stirred up by grazing bison
4. fungi residing in plant roots, such as endomycorrhizae

Removing a keystone species from the community will eventually allow for the invasion of a new species.

1. Removing a keystone species from the community drastically reduces diversity.
2. A keystone species has little interaction with other species in an environment.
3. Adding a keystone species to the community will make it more diverse.

Which of the following studies would shed light on the mechanism of spread of H5N1 virus from Asia?

1. Test for the presence of H5N1 in poultry used for human consumption worldwide.
2. Locate and destroy birds infected with H5N1 in Asian open-air poultry markets.
3. Test fecal samples for H5N1 in Asian waterfowl that live near domestic poultry farms in Asia.
4. Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected birds show up in Alaska.

Food chains are sometimes short because _____.

1. only a single species of herbivore feeds on each plant species
2. local extinction of a species causes extinction of the other species in its food chain
3. predator species tend to be less diverse and less abundant than prey species
4. most of the energy in a trophic level is lost as it passes to the next higher level