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 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.

Even a slight reproductive advantage will eventually lead to the elimination of the less well

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

niche

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

slight variations in a species’ niche that allow similar species to coexist

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 found to be nocturnal. You
have discovered an example of
A) mutualism.
B) character displacement.
C) Batesian mimicry.
D) facultative commensalism.
E) resource partitioning.

resource partitioning.

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.

sympatric populations of species with similar ecological niches.

Which of the following is an example of cryptic coloration?
A) bands on a coral snake
B) brown or gray color of tree bark
C) markings of a viceroy butterfly's wings
D) colors of an insect-pollinated flower's petals
E) a "walking stick" insect that resembles a twig

a "walking stick" insect that resembles a twig

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) two species of rattlesnakes that both rattle their tails
E) two species of moths with wing spots that look like an owl's eyes

two species of unpalatable butterfly that have the same color pattern

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

a nonvenomous snake that looks like a venomous snake

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

the brightly colored patterns of poison dart frogs

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. Which of the following best describes the interactions between dwarf
mistletoes and trees?
A) mutualism
B) parasitism
C) commensalism
D) facilitation
E) competition

parasitism

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

mutualism

Which of the following would be most significant in understanding the structure of an
ecological community?
A) determining how many species are present overall
B) determining which particular species are present
C) determining the kinds of interactions that occur among organisms of different species
D) determining the relative abundance of species
E) all of the above

all of the above

Which of the following studies would a community ecologist undertake to learn about
competitive interactions?
A) selectivity of nest sites among cavity-nesting songbirds
B) the grass species preferred by grazing pronghorn antelope and bison
C) nitrate and phosphate uptake by various hardwood forest tree species
D) stomach analysis of brown trout and brook trout in streams where they coexist
E) all of the above

all of the above

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

resource partitioning

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.

Interaction increases the survival and reproductive rates of mutualistic species.

How might an ecologist 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 niche size changes after the addition of nutritional resources to the habitat.
C) Observe if 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 if the species expands its range after the removal of a competitor.

Observe if the species expands its range after the removal of a competitor.

Which of the following terms is used by ecologists to describe the community interaction
where one organism makes the environment more suitable for another organism?
A) parasitism
B) mutualism
C) inhibition
D) facilitation
E) commensalism

facilitation

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

an organism's "profession" in the community

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.

keystone species

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. Take away the elephants, and 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.

Elephants exhibit a disproportionate influence on the structure of the community relative to
their abundance.

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 →

P ← C

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) Humans carefully select which species will outcompete nuisance native species.
D) Invasive species have a higher reproductive potential than native species.
E) Invasive species come from geographically isolated regions, so when they are introduced to
regions where there is more competition, they thrive.

Invasive species are not held in check by the predators and agents of disease that have always been in place for native species.

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) a means of reversing the effects of pollution by applying antidote chemicals that have a
neutralizing effect on the community.
C) an example of how one would use the bottom-up model for community restoration.
D) adjusting the numbers of each of the trophic levels back to the numbers that they were before
human disturbance.
E) monitoring and adjusting the nutrient and energy flow through a community with new
technologies.

removing many of the organisms at the next higher trophic level so that the struggling trophic
level below can recover.

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

25W, 25X, 25Y, 25Z

Why are food chains relatively short?
A) Top-level feeders tend to be more numerous than lower-trophic-level species.
B) Top-level feeders tend to be small but are capable of conserving more energy.
C) Longer chains are less stable and energy transfer between trophic levels is inefficient.
D) There are only so many organisms that are adapted to feed on other types of organisms.
E) Food chain length is ultimately determined by the photosynthetic efficiency of producers.

Longer chains are less stable and energy transfer between trophic levels is inefficient.

According to the nonequilibrium model,
A) communities will remain in a climax state if there are no human disturbances.
B) community structure remains stable in the absence of interspecific competition.
C) communities are assemblages of closely linked species that are irreparably changed by
disturbance.
D) interspecific interactions induce changes in community composition over time.
E) communities are constantly changing after being influenced by disturbances.

communities are constantly changing after being influenced by disturbances.

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. A possible factor in this secondary
succession was
A) equilibrium.
B) facilitation.
C) immigration.
D) inhibition.
E) parasitism.

inhibition.

The 1988 Yellowstone National Park lodgepole pine forest fires were likely the result of
A) overgrazing by elk.
B) infrequent rain episodes.
C) years of fire suppression by humans.
D) unextinguished campfires.
E) geysers.

years of fire suppression by humans.

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.

Habitats are opened up for less competitive species.

Species richness increases
A) as we increase in altitude in equatorial mountains.
B) as we travel southward from the North Pole to the equator.
C) on islands as distance from the mainland increases.
D) as depth increases in aquatic communities.
E) as community size decreases.

as we travel southward from the North Pole to the equator.