Chapter 14

Question 1

Among the possible interactions between species, commensalism and amensalism are not
often considered in experimental and theoretical studies. Why?
A) Such interactions are uncommon.
B) Such interactions are unimportant.
C) Such interactions lack a mutual dynamic between the two participants.
D) All of the above are true.

Answer 1

C) Such interactions lack a mutual dynamic between the two participants.

Question 2

Which of the following statements about parasites is incorrect?
A) A parasite may kill its host.
B) A parasite may increase the likelihood of its host’s dying from other causes.
C) A parasite may reduce the fecundity of its host.
D) A parasite may be specific to a single host species.

Answer 2

A) A parasite may kill its host.

Question 3

Parasitoids resemble:
A) parasites, in that they reside within and eat the tissues of a living host.
B) predators, in that they inevitably kill their hosts.
C) both A) and B).
D) neither A) nor B).

Answer 3

C) both

Question 4

Which of the following does not directly affect the abundance of its food supply?
A) predator B) parasite C) parasitoid D) herbivore E) detritivore

Answer 4

E) detritivore

Question 5

For which of the types of consumer listed below would we be least likely to refer to its food
source as a “host”?
A) predator B) parasite C) parasitoid D) herbivore E) detritivore

Answer 5

E) detritivore

Question 6

Which of the following feeds on living woody vegetation?

A) grazer B) browser

Answer 6

B) browser

Question 7

Of the following kinds of consumers, which is involved in a close association with its resource
and is highly likely to cause its death?
A) grazers and browsers
B) parasites and many arthropod herbivores
C) predators
D) parasitoids

Answer 7

D) parasitoids

Question 8

Of the following kinds of consumers, which is involved in a casual association with its resource
and is unlikely to cause its death?
A) grazers and browsers
B) parasites and many arthropod herbivores
C) predators
D) parasitoids

Answer 8

A) grazers and browsers

Question 9

In experiments with bullfrog tadpoles, Relyea and Werner showed that, in comparison to
predator‐free controls, tadpoles exposed to caged predators:
A) were more active and grew faster.
B) were more active but grew more slowly.
C) were less active but grew faster.
D) were less active and grew more slowly.

Answer 9

D) were less active and grew more slowly.

Question 10

The symbiotic bacterium, Wolbachia, infects a variety of different insect hosts. Which of the
following is true of Wolbachia?
A) It does not reduce host fitness.
B) It targets a single cell type in all host species.
C) Its most significant effects result from modification of sexual function.
D) It requires an alternate host to complete its life cycle.

Answer 10

C) Its most significant effects result from modification of sexual function.

Question 11

Some mutualistic relationships may have evolved from host‐parasite interactions.
A) True B) False

Answer 11

A) True

Question 12

The malarial parasite, Plasmodium, undergoes a complex life cycle in which asexual
reproduction occurs in ___________ and dispersal and sexual reproduction occur in
__________.
A) a vertebrate host; a mosquito B) a mosquito; a vertebrate host

Answer 12

A) a vertebrate host; a mosquito

Question 13

A vertebrate host infected with the malarial parasite, Plasmodium, typically reacts with an
inflammation (high fever) when:
A) sperm are released into the bloodstream.
B) fertilization of eggs occurs in the bloodstream.
C) sporozoites invade the salivary gland.
D) merozoites are released into the bloodstream.
E) the individual is bitten by a mosquito also carrying Plasmodium.

Answer 13

D) merozoites are released into the bloodstream.

Question 14

Which of the following is utilized by parasites to circumvent the host’s immune system?
A) production of chemical factors that suppress the immune system
B) production of surface proteins that mimic the host’s own proteins
C) continuous production of novel surface proteins
D) coating themselves with the host’s proteins
E) all of the above

Answer 14

E) all of the above

Question 15

Which of the following is utilized by schistosome species to circumvent the host’s immune
system?
A) production of chemical factors that suppress the immune system
B) production of surface proteins that mimic the host’s own proteins
C) continuous production of novel surface proteins
D) coating themselves with the host’s proteins
E) all of the above

Answer 15

D) coating themselves with the host’s proteins

Question 16

When a vertebrate host mounts an immune response to a parasite closely related to another
parasite that previously infected the same host, we refer to this phenomenon as __________.
A) virulence
B) cross-resistance
C) symbiosis
D) complex life cycle
E) inflammation

Answer 16

B) cross-resistance

Question 17

Compounds produced by plants for purposes other than metabolism, chiefly defense, are
referred to as __________ compounds.
A) primary B) secondary C) tertiary D) quaternary

Answer 17

B) secondary

Question 18

Plants produce tannins as defensive compounds that deter herbivory. Tannins reduce the
digestibility of plant material in a:
A) reaction binding carbohydrates of all types.
B) reaction binding proteins of all types.
C) reaction binding fats of all types.
D) reaction binding terpenoids of all types.
E) reaction binding phenolics of all types.

Answer 18

B) reaction binding proteins of all types.

Question 19

Tannins (previous question) are produced at relatively high levels in leaves of oaks and other
plants, whether or not the plants have been browsed by herbivores. This is an example of a(n)
__________ defense.
A) constitutive B) induced

Answer 19

A) constitutive

Question 20

Essential oils, latex, and resins fall into the broad group of plant antiherbivore defenses known
as:
A) nitrogen compounds B) terpenoids C) phenolics D) none of the above

Answer 20

B) terpenoids

Question 21

Alkaloids, which include morphine, atropine, and nicotine, are plant antiherbivore defenses
having well‐known effects on the central nervous system of vertebrates, including humans. To
which of the three broad groups of plant antiherbivore defenses do alkaloids belong?
A) nitrogen compounds B) terpenoids C) phenolics D) none of the above

Answer 21

A) nitrogen compounds

Question 22

When shoots of aspen, poplar, birch, and alder are heavily browsed by snowshoe hares, shoots
produced during the following growing season have exceptionally high concentrations of
terpenes and phenolic resins, which are extremely unpalatable to hares. This is an example of
a(n) __________ defense.
A) constitutive B) induced

Answer 22

B) induced

Question 23

Two predators consume the same prey species. Because each predator reduces the availability
of this prey organism for the other, we can refer to the interaction between the two predators
as one involving \_\_\_\_\_\_\_\_\_\_.
A) competition
B) predation
C) parasitism
D) mutualism
E) commensalism

Answer 23

A) competition

Question 24

A seedling of a saguaro cactus benefits from shade against the sun and protection from
herbivores afforded by small trees (such as ironwood and palo verde) that serve as nurse
plants. When the saguaro is small the relationship between the saguaro and its nurse plants is
an example of __________.
A) competition
B) predation
C) parasitism
D) mutualism
E) commensalism

Answer 24

E) commensalism

Question 25

A seedling of a saguaro cactus benefits from shade against the sun and protection from
herbivores afforded by small trees (such as ironwood and palo verde) that serve as nurse
plants. When the saguaro grows to maturity the relationship between the saguaro and its nurse
plants is an example of __________.
A) competition
B) predation
C) parasitism
D) mutualism
E) commensalism

Answer 25

A) competition

Question 26

The early relationship between pioneer plants and the later successional plants that replace
them is often an example of facilitation. However, once the later successional plants become
well established, the relationship between pioneers and these later successional species is an
example of __________.
A) competition
B) predation
C) parasitism
D) mutualism
E) commensalism

Answer 26

A) competition

Question 27

Rhizobium bacteria and roots of legumes form mutualistic partnerships that would be classified
as __________.
A) trophic B) defensive C) dispersive

Answer 27

A) trophic

Question 28

The kind of mutualism studied by Daniel Janzen between Acacia plants and Pseudomyrmex ants
would be classified as __________.
A) trophic B) defensive C) dispersive

Answer 28

B) defensive

Question 29

Based on your knowledge of the three general categories of mutualism, choose from the
following list the order that ranks these from less restrictive to more restrictive. (Hint: By
restrictive, we mean a relationship that involves specialization on the parts of the participants.)
A) trophic, dispersive, defensive C) dispersive, defensive, trophic
B) dispersive, trophic, defensive

Answer 29

C) dispersive, defensive, trophic

Question 30

Among dispersive mutualisms, which of the following tends to be more restrictive?
A) seed dispersal mutualisms C) They are equally restrictive.
B) plant‐pollinator mutualisms

Answer 30

B) plant‐pollinator mutualisms

Question 31

Although they differ in their mode of action on resource populations, predators, herbivores,
and parasites are alike in that they are considered __________.

Answer 31

consumers

Question 32

Consumer‐resource interactions organize biological communities into __________.

Answer 32

food chains

Question 33

__________ consume dead organic material.

Answer 33

Detritivores

Question 34

When two species live in close association (example: algae and fungi constituting lichens), we
refer to this relationship as a __________ .

Answer 34

symbiosis

Question 35

The immune systems of vertebrates can produce __________ that recognize and bind to
foreign proteins, such as those on the surfaces of parasites.

Answer 35

antibodies

Question 36

Plant compounds that are used primarily for defensive purposes instead of metabolism are
referred to as __________.

Answer 36

secondary compounds

Question 37

Spines, hairs, tough seed coats, and sticky gums and resins are all examples of plant defenses
against __________.

Answer 37

herbivory

Question 38

Essential oils, latex, and resins are all included in a broad class of secondary plant compounds
called \_\_\_\_\_\_\_\_\_\_.

Answer 38

terpenoids

Question 39

When heavily browsed by snowshoe hares, shoots of aspen, poplar, birch, and alder produced
in the following year have high concentrations of unpalatable terpenes and phenolic resins. This
is an example of an __________ plant antiherbivore defense.

Answer 39

inducible

Question 40

Specialized fishes and shrimp remove parasites from various fish species in a __________
mutualism.

Answer 40

defensive