Campbell Biology in Focus, 2e (Urry)
Chapter 41 Species Interactions
41.1 Multiple-Choice Questions
1) Which of the following statements is consistent with the principle of competitive exclusion?
A) Bird species generally do not compete for nesting sites.
B) The random distribution of one competing species will have a positive impact on the
population growth of the other competing species.
C) Two species with the same fundamental niche will exclude all other competing species.
D) Even a slight reproductive advantage will eventually lead to the elimination of the less well
adapted of two competing species.
E) Natural selection tends to increase competition between related species.
2) According to the competitive exclusion principle, two species cannot continue to occupy the
same
A) habitat.
B) niche.
C) territory.
D) range.
E) biome.
3) Which of the following best describes resource partitioning?
A) competitive exclusion that results in the success of the superior species
B) slight variations in a species’ niche that allow similar species to coexist
C) two species that can coevolve to share identical niches
D) differential resource utilization that results in a decrease in community species diversity
E) a climax community that is reached when no new niches are available
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 dawn in areas without the other
species. 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. You have
discovered an example of
A) mutualism.
B) Batesian mimicry.
C) commensalism.
D) resource partitioning.
5) Resource partitioning would be most likely to occur between
A) sympatric populations of a predator and its prey.
B) sympatric populations of species with similar ecological niches.
C) sympatric populations of a flowering plant and its specialized insect pollinator.
D) allopatric populations of the same animal species.
E) allopatric populations of species with similar ecological niches.
6) Which of the following is an example of cryptic coloration?
A) highly contrasting bands on a coral snake
B) brown or gray color of tree bark
C) bright markings of a viceroy butterfly’s wings
D) orange or yellow colors of an insect-pollinated flower’s petals
E) a walking stick, which is an insect that resembles a twig
7) Which of the following is an example of Batesian mimicry?
A) an insect that resembles a twig
B) a butterfly that resembles a leaf
C) a nonvenomous snake that looks like a venomous snake
D) a fawn with fur coloring that camouflages it in the forest environment
E) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
8) Which of the following is an example of aposematic coloration?
A) the brightly colored patterns of poison dart frogs
B) eye color in humans
C) green color of a plant
D) colors of an insect-pollinated flower
E) a katydid whose wings look like a dead leaf
9) 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 and can be harmed if nutrients and water are scarce in the environment. Which
of the following best describes the interactions between dwarf mistletoes and trees?
A) mutualism
B) parasitism
C) commensalism
D) facilitation
E) competition
10) Evidence shows that some grasses benefit from being grazed. Which of the following terms
would best describe this plant-herbivore interaction?
A) mutualism
B) commensalism
C) parasitism
D) competition
E) predation
11) White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows
of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the
bottom of the tree trunk toward the top, whereas the white-breasted nuthatch searches from the
top of the trunk down. These hunting behaviors best illustrate which of the following ecological
concepts?
A) competitive exclusion
B) resource partitioning
C) character displacement
D) keystone species
E) bottom-up and top-down hypotheses
12) Which statement best describes the evolutionary significance of mutualism?
A) Mutualism offers more biodiversity to a community.
B) Individuals partaking in a mutualistic relationship are more resistant to parasites.
C) Interaction increases the survival and reproductive rates of mutualistic species.
D) Mutualistic interaction lessens competition in communities where it is present.
E) Mutualistic relationships allow organisms to synthesize and use energy more efficiently.
13) How might an ecologist test whether a species is occupying its complete fundamental niche
or only a portion of it?
A) Study the temperature range and humidity requirements of the species.
B) Observe whether the niche size changes after the addition of nutritional resources to the
habitat.
C) Observe whether the niche size changes after the introduction of a similar non-native species.
D) Measure the change in reproductive success when the species is subjected to environmental
stress.
E) Observe whether the species expands its range after the removal of a competitor.
14) Which of the following terms is used by ecologists to describe the community interaction in
which one organism makes the environment more suitable for another organism?
A) parasitism
B) herbivory
C) inhibition
D) facilitation
E) commensalism
15) How did Eugene Odum describe an ecological niche?
A) the “address” of an organism
B) an entity that is synonymous with an organism’s specific trophic level
C) an organism’s “profession” in the community
D) the organism’s role in recycling nutrients in its habitat
E) the interactions of the organism with other members of the community
16) In a tide pool, 15 species of invertebrates were reduced to 8 after one species was removed.
The species removed was likely a(n)
A) pathogen.
B) keystone species.
C) herbivore.
D) resource partitioner.
E) mutualistic organism.
17) Elephants are not the most dominant species in African grasslands, yet they influence
community structure. The grasslands contain scattered woody plants, but they are kept in check
by the uprooting activities of the elephants. If the elephants are taken away, the grasslands
convert to forests or to shrublands. The newly growing forests support fewer species than the
previous grasslands. Which of the following describes why elephants are the 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 prevent drought in African grasslands.
D) Elephants are the biggest herbivore in this community.
E) Elephants help other populations survive by keeping out many of the large African predators.
18) 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 on its prey (P) population, but not vice versa?
A) P ← C
B) P → C
C) C ↔ P
D) P ← C → P
E) C ← P →
19) Which of the following is a likely explanation for why invasive species take over
communities into which they have been introduced?
A) Invasive species are less efficient than native species in competing for the limited resources
of the environment.
B) Invasive species are not held in check by the predators and agents of disease that have always
been in place for native species.
C) Invasive species have a higher reproductive potential than native species.
D) Invasive species come from geographically isolated regions, so when they are introduced to
regions where there is more competition, they thrive.
20) Biomanipulation can best be described as
A) removing many of the organisms at the next higher trophic level so that the struggling trophic
level below can recover.
B) an example of how one would use the bottom-up model for community restoration.
C) adjusting the numbers of each of the trophic levels back to the numbers that they were before
human disturbance.
D) monitoring and adjusting the nutrient and energy flow through a community with new
technologies.
21) Imagine five forest communities, each with 100 individuals distributed among four different
tree species (W, X, Y, and Z). Which forest community would be most diverse?
A) 25W, 25X, 25Y, 25Z
B) 40W, 30X, 20Y, 10Z
C) 50W, 25X, 15Y, 10Z
D) 70W, 10X, 10Y, 10Z
E) 100W, 0X, 0Y, 0Z
22) In a lake with three trophic levels (fish, zooplankton, algae), how might an algal bloom be
prevented?
A) Remove the fish.
B) Remove the zooplankton.
C) Add nutrient fertilizers.
D) Add fish.
23) The feeding relationships between species in a community is called
A) biomass.
B) trophic structure.
C) top-down control.
D) bottom-up control.
24) According to the nonequilibrium model,
A) community structure remains stable in the absence of interspecific competition.
B) communities are assemblages of closely linked species that are irreparably changed by
disturbance.
C) interspecific interactions induce changes in community composition over time.
D) communities are constantly changing after being influenced by disturbances.
25) In a particular case of secondary succession, three species of wild grass invaded a field. A
fourth species’ seeds were also dispersed to this field, but despite being adapted to the abiotic
conditions, this fourth species did not establish. A possible factor in this secondary succession
was
A) equilibrium.
B) facilitation.
C) immigration.
D) inhibition.
E) parasitism.
26) What contributed to the 1988 Yellowstone National Park lodgepole pine forest fires?
A) overgrazing by elk
B) drought
C) unextinguished campfires
D) geysers
27) Why do moderate levels of disturbance result in an increase in community diversity?
A) Habitats are opened up for less competitive species.
B) Competitively dominant species infrequently exclude less competitive species after a
moderate disturbance.
C) The environmental conditions become optimal.
D) The resulting uniform habitat supports stability, which in turn supports diversity.
E) Less-competitive species evolve strategies to compete with dominant species.
28) What are usually the first photosynthetic organisms to colonize during primary succession?
A) shrubs
B) lichens
C) trees
D) grasses
29) During primary succession at Glacier Bay, what is the composition of the oldest
communities on well-drained slopes?
A) primarily Dryas
B) liverworts, mosses, fireweed, scattered Dryas, and willows
C) sphagnum moss
D) spruce and hemlock
E) primarily alder
30) Species richness increases
A) as evapotranspiration decreases.
B) as we travel southward from the North Pole to the equator.
C) on islands as distance from the mainland increases.
D) in communities experiencing frequent disturbance events.
31) There are more species in tropical areas than in places more distant from the equator. This is
probably a result of
A) fewer predators.
B) more intense annual solar radiation.
C) more frequent ecological disturbances.
D) fewer agents of disease.
32) Why do tropical communities tend to have greater species diversity than temperate or polar
communities?
A) They are less likely to be affected by human disturbance.
B) There are fewer parasites to negatively affect the health of tropical communities.
C) Tropical communities are low in altitude, whereas temperate and polar communities are high
in altitude.
D) Tropical communities are generally older than temperate and polar communities.
E) More competitive dominant species have evolved in temperate and polar communities.
33) Which of the following is a correct statement about the MacArthur/Wilson Island
Equilibrium Model?
A) The more species that inhabit an island, the lower the extinction rate.
B) As the number of species on an island increases, the emigration rate decreases.
C) Competitive exclusion is less likely on an island that has large numbers of species.
D) Small islands receive few new immigrant species.
E) Islands closer to the mainland have higher extinction rates.
34) What is an evolutionary factor that influences the species richness of a community?
A) amount of sunlight
B) amount of precipitation
C) speciation rate
D) geographic size
E) distance to other communities
35) Tuberculosis is an infectious disease of humans that is caused by the bacteria Mycobacterium
tuberculosis. Symptoms of a tuberculosis infection can include fever and damage to the lungs.
How should the interaction between pathogens and their hosts be classified?
A) mutualism
B) commensalism
C) competition
D) exploitation
36) Which of the following best describes the consequences of white-band disease in Caribbean
coral reefs?
A) Staghorn coral has been decimated by the pathogen, and elkhorn coral has taken its place.
B) Key habitat for lobsters, snappers, and other reef fishes has improved.
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.
E) Other coral species take the place of the affected staghorn and elkhorn species.