Deck 54: Biodiversity and Communities

Question 1

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 behind and eat any insects or small vertebrates that had flown jumped away from the moving swarm. Which of the following species interactions does this example demonstrate between the birds and the ants?

A) consumption
B) commensalism
C) parasitism
D) mutualism

Answer 1

B

Question 2

Use the figures to answer the following question. In this experiment, Balanus balanoids was removed from the habitat shown on the left, obtaining the results shown on the right.
Which of the following statements is supported by the results of this experiment?

A) B. balanoids can survive only in the lower intertidal zone because it is unable to resist desiccation.
B) B. balanoids is inferior to C. stellatus in competing for space on rocks lower in the intertidal zone.
C) When the two species of barnacles compete with each other, both species still occupy low and high tide areas.
D) Competition with B. balanoids prevented C. stellatus from occupying the lower tide region of its fundamental niche.

Answer 2

D

Question 3

Use the figures to answer the following question. This experiment by Connell was best designed to investigate which of the following?

A) character displacement in the color of barnacles
B) habitat preference in two different species of barnacles
C) how sea-level changes affect barnacle distribution
D) competitive exclusion and distribution of barnacle species

Answer 3

D

Question 4

As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at night when present in an area where the other beetle species is absent. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are found to be nocturnal. Which of the following conclusions is best supported by this scientific evidence?

A) the two-spot beetle species may be competitively displacing the three-spot beetle species
B) the three-spot beetle species may be competitively displacing the two-spot beetle species
C) the two beetle species do not compete for prey when sharing an area
D) the two beetle species prefer to feed during the daytime

Question 5

Which of the following is an example of aposematic coloration?

A) a non-poisonous snake mimics the color of a poisonous one
B) the brightly colored patterns of monarch butterfly caterpillars
C) green color of a plant
D) a katydid whose wings look like a dead leaf

Question 6

As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at night when present in an area where the other beetle species is absent. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are nocturnal. The observations above indicate that the two species most likely demonstrate which of following ecological processes? You have discovered an example of ________.

A) mutualism
B) character displacement
C) Batesian mimicry
D) resource partitioning

Question 7

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

A) change its fundamental niche
B) decline in abundance
C) become the target of specialized parasites
D) expand its realized niche

Question 8

Character displacement differs from resource partitioning because character displacement ________.

A) is a fundamental difference in feeding behaviors of individuals
B) is directly linked to the evolution of genotypes that have allowed alternate resource use
C) is a difference in the niche within a habitat that is preferred to be used by a species
D) is not the result of competition

Question 9

Using the symbols +, −, and 0 to indicate interspecific species interactions, where the first symbol refers to the first organism mentioned, which of the following claims/statements is correct?

A) +/0 will always remain such.
B) A +/− interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes.
C) Species interactions occur in isolation and cannot affect the structure of ecological communities.
D) A −/− interaction benefits both of the species in the relationship.

Question 10

Use the figure to answer the following question. Which of the following conclusions is best supported from the experimental evidence in the figure?

A) Without direct contact, mussels can sense the presence of crabs.
B) Mussels can sense the presence of crabs only visually.
C) Mussels are increasing their shell thickness in response to water current.
D) Crabs hunt for mussels by focusing on the chemicals they emit into the water.

Question 11

Which of the following is an example of Müllerian mimicry?

A) two species of unpalatable butterfly that have the same color pattern
B) a day-flying hawkmoth that looks like a wasp
C) a chameleon that changes its color to look like a dead leaf
D) one species of a nonvenomous snake which rattles its tail to mimic a venomous rattlesnake

Question 12

Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes, yet they are sometimes negatively affected by this interaction. Which of the following best describes the interactions between dwarf mistletoes and trees?

A) mutualism
B) commensalism
C) competition
D) facilitation

Question 13

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

A) The random distribution of one competing species will have a positive impact on the population growth of the other competing species.
B) If two species have the same fundamental niche, neither one will exclude the other competing species.
C) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
D) Natural selection tends to increase competition between related species.

Question 14

Use the figure to answer the following question. 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. Which of the following conclusions is best supported by the data provided in the figure?

A) Ants do somehow protect the treehoppers from spiders.
B) Ants eat the honeydew produced by treehoppers.
C) Ants reduce the numbers of treehoppers.
D) No specific conclusions can be drawn from this figure.

Question 15

Use the figure to answer the following question. 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. During the first part of July, researchers found no difference between treehopper populations in any of their control and experimental groups. Which of the following measurements, if subsequently completed, would provide data to explain the researchers' result?

A) Measure the number of ant females.
B) Measure the relative sizes of the treehoppers.
C) Measure the relative abundance of jumping spiders.
D) Measure the relative sizes of different ant species.

Question 16

Resource partitioning would be most likely to occur between ________.

A) sympatric populations of species with similar ecological niches
B) sympatric populations of a flowering plant and its specialized insect pollinator
C) allopatric populations of the same animal species
D) allopatric populations of species with similar ecological niches

Question 17

Which of the following is an example of a commensalism?

A) fungi residing in plant roots, such as endomycorrhizae
B) bacteria fixing nitrogen on the roots of some plants
C) rancher ants that protect aphids in exchange for sugar-rich honeydew
D) cattle egrets eating insects stirred up by grazing bison

Question 18

Use the figures to answer the following question. In this experiment, Balanus balanoides (a species of barnacle), was removed from the habitat shown on the left. Which of the following statements is consistent with the experimental results (see the diagram on the right)?

A) The fundamental and realized niches of B. balanoides and C. stellatus are identical.
B) The fundamental and realized niches of B. balanoides and C. stellatus are different.
C) The fundamental and realized niches of B. balanoides are different, but the fundamental and realized niches of C. stellatus are identical.
D) The fundamental and realized niches of C. stellatus are different.

Question 19

Using the symbols +, −, and 0 to indicate interspecific species interactions, where the first symbol refers to the first organism mentioned, which interactions of the following would exist between a lion pride and African wild dogs, if the dogs are the lions' prey and are found to typically avoid areas with lions?

A) +/+
B) +/−
C) 0/0
D) −/−

Question 20

Which of the following is an example of Batesian mimicry?

A) a butterfly that resembles a leaf
B) a nonvenomous larva of a moth that moves like a venomous snake
C) a fawn with fur coloring that camouflages it in the forest environment
D) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish

Question 21

Use the figure to answer the following question. In the figure, species A through F are found among four communities, with the number of circles representing their abundance. Which community has the highest diversity?

A) an invasive species
B) a keystone species
C) a primary producer
D) a secondary consumer

Question 22

Use the following diagram of a hypothetical food web to answer the question. In this particular scenario, the arrows represent the transfer of energy between the various organisms and decomposers are included in the diagram. Which letter best represents a producer in the community?

A) A
B) B
C) D
D) E

Question 23

Use the figures to answer the following question. The different shaded squares in the figure, from white to darker gray, represent different species, and more squares of a shade correspond to a higher abundance. According to the Shannon Diversity Index, which of the five blocks above, with each containing 36 squares, represents the greatest diversity?

A) 1
B) 2
C) 4
D) 5

Question 24

Elephants are not the most abundant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but these woody plants remain relatively uncommon because of the uprooting activities of the elephants. If elephants were removed, the grasslands eventually are converted to forests or to shrublands. These newly growing forests support fewer species than the previous, more biodiverse grasslands. Which of the following statements best supports the elephants' role as a keystone species in this scenario?

A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.
B) Grazing animals depend upon the elephants to convert forests to grassland.
C) Elephants are the biggest herbivore in this community.
D) Elephants help other populations survive by keeping out many of the large African predators.

Question 25

Which of the following studies would provide a community ecologist with the most pertinent data with which to investigate competitive interactions?

A) selectivity of nest sites among cavity-nesting songbirds
B) the grass species preferred by grazing pronghorn antelope and bison
C) stomach analysis of brown trout and brook trout in streams where they coexist
D) all of these

Question 26

Five hypothetical forest communities, each have one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which of the following combinations of species in a forest community would make it the most diverse?

A) 25W, 25X, 25Y, 25Z
B) 40W, 30X, 20Y, 10Z
C) 50W, 25X, 15Y, 10Z
D) 70W, 10X, 10Y, 10Z

Question 27

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 able to fly. These results indicate which of the following?
(P) Bouchard and D. R. Brooks, Effect of vagility potential on dispersal and speciation in rainforest insects, Journal of Evolutionary Biology 17: 994-1006 [2004].)

A) Flightless insects have a greater dispersal potential from this study area.
B) Flightless insects are more numerous in the study area.
C) Flightless insects have a higher species richness in the study area.
D) Flightless insects are better suited for the tropics.

Question 28

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? In this particular scenario, the arrows between species indicate the direction of control between the populations of organisms.

A) P ← C
B) P → C
C) C ↔ P
D) P ← C → P

Question 29

Use the graph to answer the following question. Which of the following is the best conclusion about the effect of a keystone species, based on the graphed data?

A) A keystone species has little interaction with other species in an environment.
B) Removing a keystone species from the community drastically reduces species richness.
C) Adding a keystone species to the community will make it more diverse.
D) Removing a keystone species from the community will eventually allow for the invasion of a new species.

Question 30

Using the symbols +, −, and 0 to indicate interspecific species interactions, where the first symbol refers to the first organism mentioned, what interactions exist between cellulose-digesting organisms in the gut of a termite and the termite?

A) +/+
B) +/0
C) +/−
D) 0/0

Question 31

Determining which of the following would be most helpful in understanding the structure of an ecological community?

A) which and how many species are present overall
B) which particular species are absent
C) the kinds of interactions that occur among individuals of the same species
D) the abundance of resources available for one species

Question 32

Red-cheeked salamanders are partially protected from predators because of cardiac glycosides they produce from glands on their back. When ingested, cardiac glycosides disrupt normal heart rhythms. A different salamander species, the imitator salamander, also has red cheek patches, but does not produce cardiac glycosides. It does gain protection from predators that have learned to avoid red-cheeked salamanders. This relationship has which of the following effects on the population dynamics of both species?

A) Both species are negatively affected.
B) Both species are positively affected.
C) The red-cheeked salamander is positively affected; the imitator is negatively affected.
D) The red-cheeked salamander is not affected; the imitator is positively affected.

Question 33

Use the figure to answer the following question. In the figure, species A through F are found among four communities, with the number of circles representing their abundance. Which community has the highest diversity?

A) community 1
B) community 2
C) community 3
D) community 4

Question 34

Which of the following would be the best experiment for an ecologist to conduct to test whether a species is occupying all of its fundamental niche or only a portion of it?

A) Study the temperature range and humidity requirements of the species.
B) Observe if the species expands its range after the removal of a competitor.
C) Measure the change in reproductive success when the species is subjected to environmental stress.
D) Observe if the niche size changes after the introduction of a similar non-native species.

Question 35

Approximately how many kilograms (kg) of carnivore (secondary consumer) biomass can be supported by an area of a field containing 1,000 kg of plant material (assuming 10% efficiency in energy transfer)?

A) 1,000
B) 100
C) 10
D) 1

Question 36

Use the following diagram of a hypothetical food web to answer the question. In this particular scenario, the arrows represent the transfer of energy between the various organisms and decomposers are included in the diagram. Which letter best represents a primary consumer in the community?

A) A
B) B
C) C & D
D) D only

Question 37

Using the symbols +, −, and 0 to indicate interspecific species interactions, where the first symbol refers to the first organism mentioned, what interactions exist between mycorrhizae and evergreen tree roots?

A) +/+
B) +/0
C) +/−
D) 0/0

Question 38

Which of the following statements is a well-supported hypothesis for why some introduced species become highly abundant and may take over communities into which they have been introduced, but meanwhile do not exhibit this outcome in their original ranges?

A) Invasive species are less efficient than native species in competing for the limited resources of the introduced environment.
B) Invasive species populations in the introduced range are not controlled by the predators and agents of disease, or may experience less competition.
C) Invasive species always have a higher reproductive potential than other species.
D) Invasive species come from geographically isolated regions, so when they are introduced to regions where there is more competition, they thrive.

Question 39

Approximately how much total biomass of plant material would hypothetically be necessary to support six carnivorous lions (whose diet consists only of herbivorous prey), each weighing 50 kg, living in a given area along with their prey, on an ongoing basis? (Assume a 10% efficiency in energy transfer.)

A) 130,000 kg
B) 30,000 kg
C) 3,000 kg
D) 1,500 kg

Question 40

If there are 25 African elephants (primary consumer) living together in a given area, with an average weight of 4,000 kg each, approximately how much biomass of plant material would hypothetically be necessary as a harvestable food supply to support all of them on an ongoing basis? (Assume a 10% efficiency in energy transfer.)

A) 1,000,000 kg
B) 100,000 kg
C) 50,000 kg
D) 25,000 kg

Question 41

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 solar radiation on competition among plants
C) influence of soil nutrients on the abundance of grasses versus wildflowers
D) effect of grazing intensity by bison on plant species diversity

Question 42

Use the following diagram of five islands formed at around the same time near a particular mainland, as well as the principles of MacArthur and Wilson's island equilibrium model, to answer the question. Which island would likely have the lowest extinction rate?

A) 1
B) 3
C) 4
D) 5

Question 43

Which of the following best explains why there are more species in tropical regions than in locations more distant from the equator?

A) fewer predators and parasites
B) more dispersed annual solar radiation compared to the poles
C) more frequent ecological disturbances over a longer time span
D) a longer time frame without disturbances for evolution and speciation

Question 44

According to the island equilibrium model, species richness would be lowest on an island with which of the following characteristics?

A) large and close to a mainland
B) large and remote
C) small and remote
D) small and close to a mainland

Question 45

Which of the following best explains why moderate levels of disturbance result in an increase in community diversity?

A) Habitat is opened up for less competitive species.
B) Competitively dominant species infrequently exclude less competitive species after a moderate disturbance.
C) The resulting uniform habitat supports stability, which in turn supports diversity.
D) Less-competitive species evolve strategies to compete with dominant species.

Question 46

Which of the statements below best describes a zoonotic disease?

A) It is caused by suborganismal pathogens such as viruses, viroids, and prions only.
B) It is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector.
C) It can only be spread from animals to humans through direct contact.
D) It can only be transferred from animals to humans by means of an intermediate host.

Question 47

Which of the following best explains why a pathogen is generally more virulent in a new habitat?

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

Question 48

Which of the following studies would provide the most reliable evidence to understand the mechanism of spread of H5N1 virus from Asia to North America?

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

Question 49

Use the following diagram of five tropical islands formed at around the same time near a particular mainland, as well as the principles of MacArthur and Wilson's island equilibrium model, to answer the question. Which island would likely encounter the highest rate of species extinction if these islands were subject to unregulated, commercial logging in the rainforest?

A) 1
B) 2
C) 3
D) 5

Question 50

Which description below is most consistent with the nonequilibrium model of community diversity?

A) community structure remains stable in the absence of interspecific competition
B) communities are assemblages of closely linked species that are permanently changed by disturbance
C) interspecific interactions induce changes in community composition over time
D) communities are constantly changing after being influenced by disturbances

Question 51

Which of the following is a correct statement about MacArthur and Wilson's island equilibrium model?

A) As the number of species on an island increases, the emigration rate decreases.
B) Competitive exclusion is less likely on an island that has large numbers of species.
C) Small islands receive few new immigrant species.
D) Islands closer to the mainland have higher extinction rates.

Question 52

Which of the following behaviors results in keystone predators maintaining species diversity in a community?

A) competitively exclude other predators
B) prey on the community's competitively dominant species
C) allow immigration of other predators
D) prey only on the least abundant species in the community

Question 53

Which of the following best explains why food chains are sometimes short?

A) only a single species of herbivore feeds on each plant species
B) local extinction of a species causes extinction of the other species in its food chain
C) the transfer of energy from one trophic level to the next higher level is inefficient
D) predator species tend to be less diverse and less abundant than prey species

Question 54

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?

A) There are fewer parasites to negatively affect the health of tropical communities.
B) Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude.
C) Tropical communities have higher sunlight and precipitation, and are generally older than temperate or polar communities.
D) More competitive dominant species have evolved in temperate and polar communities.

Question 55

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field and the other two species had a lower relative abundance. A possible factor contributing to the abundances of these species in this example of secondary succession is ________.

A) equilibrium
B) immigration
C) inhibition
D) parasitism

Question 56

Which claim best explains the observation that species richness is higher in tropical regions than in temperate regions?

A) tropical communities are younger
B) tropical regions generally have more available water and higher levels of solar radiation
C) higher temperatures cause more rapid speciation
D) tropical regions have very high rates of immigration and very low rates of extinction

Question 57

Biological communities may show a highly predictable and interrelated structure, or alternatively, the individual species may appear to operate independently. If a researcher were to set up many identical sterilized ponds in the same area and allowed them to be colonized, which result would support the idea that species operate independently?

A) Identical plankton communities will develop in all ponds.
B) Similar plankton communities will develop in all ponds.
C) Different plankton communities will develop in all ponds.
D) Limited plankton communities will develop in all ponds.

Question 58

Use the following diagram of five islands formed at around the same time near a particular mainland, as well as the principles of MacArthur and Wilson's island equilibrium model, to answer the question. Which region would likely have the greatest species diversity?

A) island 1
B) island 3
C) island 4
D) the mainland

Question 59

Which of the following increases community diversity, based on the intermediate disturbance hypothesis?

A) frequent immigrations of new species
B) stable conditions with no disturbance
C) moderate levels of disturbance
D) intensive disturbance by humans

Question 60

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

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

Question 61

Predators that are keystone species can maintain species diversity in a community if they ________.

A) competitively exclude other predators
B) prey on the community's competitively dominant species
C) reduce the number of disruptions in the community
D) prey only on the least abundant species in the community

Question 62

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

A) tropical communities are younger
B) tropical regions generally have more available water and higher levels of solar radiation
C) higher temperatures cause more rapid speciation
D) diversity increases as evapotranspiration decreases

Question 63

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

A) large and remote
B) small and remote
C) large and close to a mainland
D) small and close to a mainland

Question 64

The feeding relationships among the species in a community determine the community's ________.

A) secondary succession
B) ecological niche
C) species richness
D) trophic structure

Question 65

The oak tree pathogen that causes sudden oak death, Phytophthora ramorum, has dispersed 800 kilometers in 15 years. West Nile virus spread from New York State to 46 other states in 5 years. Which of the following best explains the difference in the rate of spread of these two pathogens?

A) the lethality of each pathogen
B) the mobility of their hosts
C) the fact that viruses are very small
D) innate resistance

Question 66

Scientists interested in how populations interact within communities are attempting to determine the species diversity of an island under study. Which of the following data would be most helpful to the scientists in determining diversity?

A) the number of different species on the island and the size of the population of each species
B) the number of species on the island that are consumers, producers, and decomposers
C) the relative biomass of each species on the island separated by trophic level
D) the number of trophic levels on the island and the niche of each species

Question 67

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

A) frequent massive disturbance
B) stable conditions with no disturbance
C) moderate levels of disturbance
D) human intervention to eliminate disturbance

Question 68

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

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

Question 69

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 temperature on competition among plants
C) influence of soil nutrients on the abundance of grasses versus wildflowers
D) effect of grazing intensity by bison on plant species diversity

Question 70

Food chains are sometimes short because ________.

A) only a single species of herbivore feeds on each plant species
B) local extinction of a species causes extinction of the other species in its food chain
C) the transfer of energy from one trophic level to the next higher level is inefficient
D) most producers are inedible

Question 71

The principle of competitive exclusion states that ________.

A) two species cannot coexist in the same habitat
B) competition between two species always causes extinction or emigration of one species
C) two species that have exactly the same niche cannot coexist in a community
D) two species will stop reproducing until one species leaves the habitat