Chapter.15 Exam Questions Mutualism

Ecology, 8e (Molles)

Chapter 15 Mutualism

1) Which of the following organisms are dependent on mutualisms for their persistence?

A) Reef-building corals

B) Bioluminescent fishes

C) Bumblebees and hummingbirds

D) Horses, elephants, and camels

E) All of the choices are correct.

2) Mycorrhizal fungi (directly) help their plant partners acquire

A) sugars.

B) sunlight.

C) seed dispersal.

D) soil nutrients.

E) pollination.

3) Mycorrhizal fungi acquire ________ from their plant partners.

A) sugars

B) soil nutrients

C) proteins and lipids

D) growth hormones

E) protection from consumers

4) Soil fertilization should favor mycorrhizal fungi that are

A) less aggressive at obtaining sugars from their plant hosts.

B) more aggressive at obtaining sugars from their plant hosts.

C) more efficient at extracting inorganic nutrients from soils.

D) more efficient at extracting sugars from soils.

E) more efficient at extracting inorganic nutrients from plant root exudates.

5) In experiments with the prairie grass Andropogon, root:shoot ratios proved to be

A) higher in plants grown in poor soils.

B) lower in plants grown in poor soils.

C) equal in plants grown in poor and rich soils.

D) higher in plants grown with mycorrhizae.

E) equal in plants grown with and without mycorrhizae.

6) Ants on the aspen sunflower, Helianthella quinquenervis, obtain sugars and amino acids by

A) collecting nectar from the sunflower's flowers.

B) collecting nectar from extrafloral nectaries.

C) tending aphids that extract plant sap.

D) extracting plant sap directly by piercing the sunflower stem.

E) All of the choices are correct.

7) Ant-acacia trees provide several services to their mutualistic ant partners. These include

A) enlarged thorns to host ant colonies.

B) nectar from foliar nectaries.

C) nectar from floral nectaries.

D) both enlarged thorns to host ant colonies and nectar from foliar nectaries.

E) All of the choices are correct.

8) The major benefit obtained by aspen sunflower, Helianthella quinquenervis, from its ant mutualists is

A) reduced losses of seeds to seed predators.

B) reduced loss of leaf tissue to herbivorous insects.

C) more efficient extraction of soil nutrients.

D) more rapid growth early in the growing season.

E) improved attraction of pollinators.

9) Which aspects of the biology of zooxanthellae are controlled by their coral hosts?

A) Their cell wall chemistry

B) Their population growth rate when free-living

C) The release of photosynthetic products from their cells

D) The rate at which they absorb sugars from their hosts

E) Their mortality rate

10) The major benefit obtained by zooxanthellae algal cells from their coral host is

A) protection from herbivores.

B) sugars.

C) phosphorus from coral wastes.

D) nitrogen from coral wastes.

E) temperature regulation.

11) Crabs and shrimp associated with corals protect their hosts from

A) being dislodged from the substrate by currents.

B) predation by sea-stars.

C) predation by fishes.

D) attack by parasitic nematodes.

E) infection by pathogenic bacteria.

12) The "unsuccessful mutualists" in Kathleen Keeler's cost-benefit model of mutualism are those that

A) give benefits to their partner, but fail to receive benefits in return.

B) receive benefits from their partner, but fail to provide benefits in return.

C) neither give benefits to their partner, nor receive them in return.

D) fail to locate individuals of their mutualistic partner effectively.

E) locate mutualistic partners, but fail to overcome their defenses against colonization.

13) In Kathleen Keeler's cost-benefit model of mutualism, the condition for persistence of mutualists is pwmw + qwmu > wnm. The parameters p and q represent the

A) cost and benefit of the mutualism.

B) fitness of successful and unsuccessful mutualists.

C) frequency of "mutualist" and "nonmutualist" alleles in the population.

D) proportion of successful and unsuccessful mutualists in the population.

E) amount of herbivore protection provided by ant and non-ant defenses.

14) The interaction between honeyguide birds and the Boran people of Kenya

A) is an obligate mutualism.

B) is a facultative mutualism.

C) is exploitative, with humans benefiting but honeyguides exploited.

D) represents the only way a honeyguide can gain access to a beehive.

E) depends only on humans following birds, not on active communication by the birds.

15) An interaction between individuals of different species that benefit both partners is called

A) commensalism.

B) predation.

C) exploitation.

D) mutualism.

E) ammensalism.

16) Raine, Willmer, and Stone demonstrated that protection and pollination mutualism do not come into conflict on the swollen thorn acacia, Acacia hindsii, because

A) there is spatial separation of inflorescences and resources used by guarding ants.

B) A. hindsii inflorescences lack nectar.

C) A. hindsii inflorescences contain a chemical ant repellent.

D) All of the choices are correct.

17) Nutrient poor soils should favor mycorrhizal fungi that are

A) less aggressive at obtaining sugars from their plant host.

B) more aggressive at obtaining sugars from their plant host.

C) more efficient at extracting inorganic nutrients from soil.

D) more efficient at extracting sugars from soil.

E) more efficient at extracting inorganic nutrients from plant root exudates.

18) Which of the following is not a benefit provided by mutualistic crab and shrimp to the Pocillopora coral?

A) Protection from predators

B) Promotion of the health and integrity of coral tissue

C) Source of lipids

D) Both protection from predators and source of lipids

E) Both promotion of the health and integrity of coral tissue and source of lipids

19) The enlarged thorns of swollen thorn acacias provide ants with

A) a source of sugar.

B) a source of protein.

C) a source of fats.

D) living space.

E) a habitat for their prey species.

20) ________ mutualism describes a relationship where species are so dependent on their mutualistic relationship they cannot live in its absence.

A) Obligate

B) Critical

C) Facultative

D) Dispensable

E) Essential

21) Which of the following statements is true regarding the control of coral over zooxanthellae?

A) Coral induces zooxanthellae to release organic compounds.

B) Coral controls the rate of zooxanthellae population growth.

C) Coral controls the population density of zooxanthellae.

D) Coral promotes unbalanced growth in zooxanthellae.

E) All of the choices are true.

22) Which of the following results, from research conducted by Nancy Johnson on big blue stem grass, suggested that mycorrhizal plants had greater access to nutrients?

A) Root:shoot ratios were significantly lower in plants with mycorrhizae.

B) Root:shoot ratios were significantly higher in plants with mycorrhizae.

C) Root:shoot ratios were equal in plants with and without mycorrhizae.

D) Root:shoot ratios were highest in treatments without nitrogen supplements.

E) Root:shoot ratios were lowest in the treatment with nitrogen supplements.

23) The presence of ant mutualists on bullhorn acacia reduces herbivore attack and increases acacia growth rate, but has little effect on acacia mortality rate.

24) A cost-benefit model predicts that aspen sunflowers (Helianthella quinquenervis) in shady habitats should be less likely to attract ants than those living in sunny habitats.

25) A mutualistic relationship in which either species can survive without its partner is called a ________ mutualism.

26) The two most common types of mycorrhizal fungi are ________ and ________.

27) Modified leaflet tips of bullhorn acacia that provide a food source for ants are called ________.

28) The photosynthetic zooxanthellae associated with reef-building corals are members of the Phylum ________.

29) Interviews with Boran honey gatherers of Africa show they use which of the following characteristics of the greater honeyguide species to locate bees' nests? (Select all that apply.)

A) Guiding flights

B) Calls

C) Perch height

D) "Dance" movements

30) Unlike the ant-acacia relationship, crustaceans that associate with Pocillipora and Acropora corals, actually attract predators to the coral. 

31) Like plants, zooxanthellae receive ________ from the animal partner. In return, like mycorrhizal fungi, the ________ receives ________ compounds synthesized by zooxanthellae during photosynthesis.