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 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?

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

B) commensalism

In the hypothesis that Chthamalus stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by Balanus balanoides (another species of barnacle), what could be concluded about the two species?
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 B. balanoides are identical, but the fundamental and realized niches of C. stellatus are different.

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

What conclusion can you draw from 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.

A) Without direct contact, mussels can sense the presence of crabs.

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) resource partitioning

D) resource partitioning

In this experiment, Balanus was removed from the habitat shown on the left.
Which of the following statements is a valid conclusion of this experiment?
A) Balanus can survive only in the lower intertidal zone because it is unable to resist desiccation. B) Balanus is inferior to Chthamalus 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) The removal of Balanus shows that competitive exclusion prevented Chthamalus from occupying the lower tide region of its fundamental niche.

D) The removal of Balanus shows that competitive exclusion prevented Chthamalus from occupying the lower tide region of its fundamental niche.

Connell conducted this experiment to learn more about ________. 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

D) competitive exclusion and distribution of barnacle species

) The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. What interactions exist between a lion pride and African wild dogs, if the dogs are found to typically avoid areas with lions?

A) +/+
B) +/-
C) 0/0
D) -/-

B) +/-

) The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. Which fact is correct when describing species interactions?

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.

B) A +/- interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes.

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, 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.

C) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.

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

D) expand its realized niche

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

D) cattle egrets eating insects stirred up by grazing bison

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. From the figure, what can you conclude?
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.

A) Ants do somehow protect the treehoppers from spiders.

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 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?

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.

C) Measure the relative abundance of jumping spiders

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

A) sympatric populations of species with similar ecological niches

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

B) is directly linked to the evolution of genotypes that have allowed alternate resource use

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 non-venomous snake which rattles its tail to mimic a venomous rattlesnake

A) two species of unpalatable butterfly that have the same color pattern

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

a nonvenomous larva of a moth that moves like a venomous snake

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

B) the brightly colored patterns of monarch butterfly caterpillars

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, nor are they 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

B) commensalism

In some circumstances, grasses that initially lose tissues from being consumed by animals such as elk or cattle regrow more than they would have otherwise, and benefit from the moderate levels of grazing. Which of the following terms would best describe such a plant-herbivore interaction?
A) mutualism
B) commensalism
C) parasitism
D) predation

A) mutualism

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

1. I) determining how many species are present overall
2. II) determining which particular species are present
3. III) determining the kinds of interactions that occur among individuals of the same species
4. IV) determining the abundance of resources available for one species

A) only I and II
B) only II and IV
C) only I, II, and III
D) I, II, III, and IV

A) only I and II

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

I) II) III)

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

A) only I and II
B) only I and III
C) only II and III
D) I, II, and III

D) I, II, and III

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 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.

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

The symbols +, -, and 0 are to be used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes where individuals are not affected by interacting. 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

A) +/+

The symbols +, -, and 0 are to be used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes where individuals are not affected by interacting. 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

A) +/+

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. How does this relationship affect 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.

D) The red-cheeked salamander is not affected; the imitator is positively affected.