Chapter 13 Species Interactions & Competition

Question 1

Mutualism

Commensalism

Parasitism

Answer 1

Both species benefit

One species benefits, other does not benefit nor is harmed

One species benefits, other is harmed

Question 2

A symbiotic relationship in which both members benefit is called

Answer 2

mutualism

Question 3

The relationship between flowering plants and their insect pollinators is an example of a symbiotic relationship called

Answer 3

mutualism

Question 4

When an organism such as a tick benefits by sucking blood from a deer who is harmed, this is a symbiotic relationship called

Answer 4

parasitism

Question 5

A bird eats the insects kicked up and displaced by a cow. The cow does not benefit, but the bird does by eating the insects as food. This type of relationship is called ______.

Answer 5

commensalism

Question 6

Select all of the major kinds of symbiotic relationships.

Answer 6

Parasitism

Commensalism

Mutualism

Question 7

In a symbiotic relationship called _______ one member is benefited and the other member is neither benefited nor harmed.

Answer 7

commensalism

Question 8

In what type of symbiotic relationship do both members benefit?

Answer 8

mutualism

Question 9

If two species interact and one is harmed with no impact on the other, the interaction is classified as ______.

Answer 9

amensalism

Question 10

Select all of the examples of mutualism.

Answer 10

mycorrhizae

ants and acacia trees

flowering plants and their pollinators

Question 11

The type of competition that involves the direct interaction between individuals is ______ competition.

Answer 11

interference competition

Question 12

In what symbiotic relationship does one member benefit while the other is harmed?

Answer 12

parasitism

Question 13

Competition between members of the same population is ______ competition.

Answer 13

intraspecific competition

Question 14

Select the example of commensalism.

Answer 14

small marine fishes living among the tentacles of sea anemones

Question 15

In Toumey’s experiments investigating competition, the purpose of trenching around the perimeter of plots was to ______.

Answer 15

eliminate potential root competition

Question 16

Competition, where individuals race to consume a limiting resource, can be considered to be a form of ______ competition.

Answer 16

exploitative

Question 17

Select the statement that represents amensalism.

Answer 17

A tree shades a growing clover preventing optimum growth with no effect on the tree.

Question 18

In Tilman’s experiments with grass, the addition of nitrogen to the soil resulted in ______ plant biomass in low-density treatments as compared to high-density treatments.

Answer 18

greater

Question 19

Interference competition involves ______ interaction between individuals.

Answer 19

direct

Question 20

Self-______ is the process where greater amounts of biomass are concentrated in fewer individuals as plants grow.

Answer 20

thinning

Question 21

A scientist doing research on competition between crows and vultures would be studying ______ competition.

Answer 21

interspecific

Question 22

At the end of Toumey’s experiments, the amount of vegetation growing on the ground in the control plots was ______ the amount in the trenched plots.

Answer 22

less than

Question 23

Self-thinning is the result of ______ competition.

Answer 23

intraspecific

Question 24

The struggle between individuals for a limited resource is a form of ______ competition for that resource.

Answer 24

exploitative

Question 25

In Tilman’s experiments with grass, plants grown at higher densities had ______ biomass per plant than those grown at lower densities.

Answer 25

greater

Question 26

Under self-thinning, plant populations ______ as they grow older.

Answer 26

become less dense

Question 27

In the “−1/2 self-thinning relationship,” we would expect that plant biomass would ______ as plant density ______.

Answer 27

increase; decreases

Question 28

Competition between members of the same population is ______ competition

Answer 28

intraspecific

Question 29

The difference between the two self-thinning rules is that the “-1/2 rule” uses ______ while the “-3/2 rule” uses ______.

Answer 29

total plant biomass ; average plant biomass

Question 30

In self-thinning, the “thinning” refers to a decrease in ______.

Answer 30

population density

Question 31

In the results of their experiments with planthoppers about intraspecific competition, Denno and Roderick found that insects grown in the highest density cages were characterized by which of the following?

Answer 31

decreased body length

reduced survivorship

increased development time

Question 32

Grosholz, based on experimental results, proposed that the effects of competition between isopods were the result of ______.

Answer 32

increased cannibalism

Question 33

From the perspective of interspecific competition, we would expect that under the competitive exclusion principle, species living together will generally have ______ niches.

Answer 33

different

Question 34

In the “−1/2 self-thinning relationship,” the “−1/2” refers to the ______ of the line when plotting the log of the plant biomass against the log of plant density.

Answer 34

slope

Question 35

The beak sizes of Darwin’s finches are related to differences in ______ and those differences result in changes in fitness as some birds were able to out-compete others.

Answer 35

diet

Question 36

In the “−3/2 self-thinning rule,” we would expect individual plant biomass to ______ as plant density ______.

Answer 36

increase; decreases

Question 37

The results of mathematical models in ecology can be used to generate ______ for experimental research.

Answer 37

predictions

Question 38

Denno and Roderick proposed that the effects of the increased competition between planthoppers were the result of ______.

Answer 38

reduced food quality

Question 39

Grosholz, in his competition experiments, found that isopods grown at higher density had reduced ______ compared to those grown at lower densities.

Answer 39

survivorship

Question 40

The competitive exclusion principle states that two species with ______ niches cannot coexist indefinitely.

Answer 40

identical

Question 41

The Lotka-Volterra model assumes that ______ will diminish as a result of both intra- and interspecific competition.

Answer 41

resources

Question 42

True or false: Under the principle of competitive exclusion, beak size in Darwin’s finches should be linked to differences in feeding niches.

Answer 42

true

competition harms both members so evolution favors avoiding it where possible.

Question 43

Which of the following are considered to be characteristics of models used in ecological research?

Answer 43

man-made construct

insightful

abstraction

Question 44

In the Lotka-Volterra equations, the term α21N 1 can be thought of as the number of species ______ that is equivalent to the number of species ______ in depleting resources.

Answer 44

1 ; 2

Question 45

In the Lotka-Volterra equations, coexistence will occur when ______ competition is greater than ______ competition for both species.

Answer 45

intraspecific; interspecific

Question 46

In the Lotka-Volterra model of competition, which term is added to the logistic equation for a population to reflect the effects of the competitor?

Answer 46

αN

Question 47

The zero growth for population 2 would occur when N2 = ______.

Answer 47

N2 = K2−α21N1

Question 48

In the Lotka-Volterra equations, the competition coefficient α12 measures the effects of an individual of species _____ on species ______.

Answer 48

2 ; 1

Question 49

In the Lotka-Volterra equations, when the value of the competition coefficient (α) is greater than 1, then we can think of intraspecific competition being ______ interspecific competition.

Answer 49

less than

Question 50

In the Lotka-Volterra model, when the zero growth isoclines for both species cross, which of the following outcomes could you expect?

Answer 50

either species 1 or 2 wins

coexistence of species 1 and 2

Question 51

When a population is greater than its isocline of zero population growth, one would expect the population to ______ over time.

Answer 51

decrease

Question 52

The Lotka-Volterra competition model predicts that coexistence occurs when intraspecific competition is ______ interspecific competition.

Answer 52

stronger than

Question 53

An important condition of Gause’s experiments with Paramecium species was that ______.

Answer 53

resources were limiting

Question 54

When grown separately, the carrying capacity for each paramecium species ______ when the bacterial food supply was reduced.

Answer 54

decreased

Question 55

In the Lotka-Volterra model, when the zero growth isoclines for both speciesDO NOT CROSS, which of the following outcomes could you expect?

Answer 55

Only species 1 wins

Only species 2 wins

Question 56

When the Lotka-Volterra competition model predicts coexistence, then ______ for species 2.

Answer 56

K2 < K1/α12

Question 57

When the two species of paramecium were grown together in Gause’s paramecium experiments, reducing the food supply resulted in ______ the time taken for one of the species to go to exclusion.

Answer 57

decreasing

Question 58

True or false: When the paramecium were grown separately, the change in carrying capacity in response to a change in food supply is evidence of interspecific competition.

Answer 58

False

intraspecific

Question 59

At intermediate environmental conditions for beetles, Park found that ______ competition in the interspecific competition.

Answer 59

either species could win

Question 60

True or false: The priority effect in competition occurs when the species that establishes itself in greater numbers first, wins.

Answer 60

true

Question 61

When the two paramecium species were grown together in Gause’s paramecium experiments with just one food source, the extinction of one of the species is evidence of the ______.

Answer 61

competitive exclusion principle

Question 62

Hot and wet

Cool and dry

In between

Answer 62

T. castaneum usually dominates

T. confusum usually dominates

Either species could win

Question 63

The environmental conditions in which one of the Tribolium beetles dominates when grown together in Park’s experiments is considered that species’ ______ niche.

Answer 63

realized niche

Question 64

The priority effect in competition occurs when the species that ______ wins.

Answer 64

starts with greater numbers

Question 65

When the two species of Galium were grown in acidic soils in Tansley’s experiments, both species grew ______ when they were grown in more basic soil.

Answer 65

slower than

Question 66

The environmental conditions in which the Galium species could grow when grown separately in Tansley’s experiments can be considered their ______ niches.

Answer 66

fundamental

Question 67

In his experiments with barnacles, Connell looked at the effects of competition by transplanting ______ to the lower intertidal zone.

Answer 67

adult Chthamalus

Question 68

The environmental conditions in which the Tribolium beetles could grow in Park’s experiments without other competitors can be considered their ______ niches.

Answer 68

fundamental

Question 69

When Tansley grew the two Galium species together, one species dominated in ______.

Answer 69

its native soil type

Question 70

The environmental conditions in which one of the Galium species dominates, when they are grown together in Tansley’s experiments, is considered that species’ ______ niche.

Answer 70

realized

Question 71

In the barnacle plots where Balanus was allowed to settle, Chthamalus populations declined due to ______ by the Balanus.

Answer 71

crowding

Question 72

The local distribution of S. anglica is determined by inundation by ________ and ________.

Answer 72

tides; waves

Question 73

The environmental conditions in which Chthamalus grows, when Balanus is allowed to persist, is its ______ niche.

Answer 73

realized

Question 74

True or false: One of the factors strengthening the results of Brown’s experiments on competition between desert rats is that it was conducted at several distant locations

Answer 74

false

done at one site

Question 75

In his experiments on competition between several species of desert rodents, Brown grouped the species based upon ______ and ______.

Answer 75

size; feeding habits

Question 76

Along coastal locations with greater fetch, you would expect S. anglica to be found at a __________ in the intertidal zone as compared to more sheltered locations.

Answer 76

higher elevation

Question 77

The environmental conditions in which Chthamalus can grow, when colonization by Balanus is prevented, is its ______ niche according to Hutchinson.

Answer 77

fundamental

Question 78

Which of the following factors in Brown’s experiments with desert rats help to provide strong evidence of competition?

Answer 78

large spatial scale

long time scale

well replicated

Question 79

How did Brown restrict the movement of rodents into and out of the study plots?

Answer 79

fencing

Question 80

Granivores are organisms that feed on ______ and were divided by Brown into two groups based on their size.

Answer 80

seeds

Question 81

The expected changes in the populations of the small granivores in Brown’s experiments as a result of competition with ______.

Answer 81

large granivores

Question 82

Experiments by other researchers and Brown have ______ the results of Brown’s competition experiments supporting his hypothesis.

Answer 82

repeated

Question 83

By changing the size of holes in the fencing of the desert rodent he was studying, Brown was able to make the study plots “semipermeable” with respect to what characteristic of the rodents?

Answer 83

size

Question 84

Character displacement occurs when two species differ more from each other when their ranges ______ as compared to where they ______.

Answer 84

overlap; do not overlap

Question 85

Brown hypothesized that small holes in the fencing would lead to ______ in the populations of small granivorous rodents and ______ in the populations of small insectivorous species.

Answer 85

increases; no change

Question 86

G. fortis have larger beaks when they are sympatric to G. fulginosa in the Galápagos Islands. This characteristic displacement in beak size would suggest that the species has ______ feeding niches between these locations.

Answer 86

different

Question 87

One of the six criteria for character displacement to occur is that the observed differences between sympatric and allopatric populations must have a ______ basis.

Answer 87

genetic

Question 88

The results of Brown’s experiments were consistent with his hypothesis because the populations of small granivores ______ when Dipodomys were excluded.

Answer 88

increased

Question 89

The study of competition has gone through several phases. Organize the following in order from first (at top) to most recent (at bottom).

Answer 89

1. theoretical
2. lab models
3. experimentation
4. re-evaluation

Question 90

In re-analyzing earlier research on competition, Shoener’s and Connell’s research produced _________ conclusions about the importance of competition in nature.

Answer 90

differing

Question 91

Character displacement is more likely to occur when two species are ______.

Answer 91

sympatric

overlapping

Question 92

Character displacement in a sympatric species demonstrates the ______ outcomes of ecological interactions.

Answer 92

evolutionary

Question 93

Overall, re-analysis of competition research has found that competition is ______ force in organizing nature.

Answer 93

an important

Question 94

One of the six criteria for character displacement to occur is that differences between pairs of sympatric species must be ______ differences between allopatric populations of the same species.

Answer 94

greater than

Question 95

The re-evaluation of research on competition has led to which of the following?

Answer 95

focus on experimental design

reanalysis of past research

Question 96

The difference in results between Connell’s and Schoener’s re-analysis of competition experiments was that they used ______.

Answer 96

different studies and different criteria for analysis

Question 97

The ability of invasive species to successfully invade is a result of their superior ______ abilities.

Answer 97

competitive

Question 98

Overall, re-analysis of competition research has found that the importance of competition can vary among ______ and ______.

Answer 98

organisms

environments

Question 99

The invasive marine snail Batillaria arrived in California as an accidental tourist associated with the introduction of ______ from Japan.

Answer 99

oysters

Question 100

Competition is ______ factor in the spread of invasive species.

Answer 100

an important

Question 101

The purpose of Byers’ first experiments with the snails Cerithidea and Batilllaria was to determine the ______.

Answer 101

effects of the snails’ density on their food supply

Question 102

The spread of Batillaria from its initial colonization site has been limited due to ______.

Answer 102

lack of planktonic larvae

Question 103

The purpose of Byers’ second experiments with the snails Cerithidea and Battillaria was to determine the effects of snails’ density on ______.

Answer 103

the growth rates of the two species

Question 104

In the final step to Byers’ research on the invasive snail Batillaria, he used the results from his first two sets of experiments to ______.

Answer 104

develop a computer model of the interaction between Cerithidia and Battillaria

Question 105

Byers was able to demonstrate the potential for resource competition among snails because diatom (algae) cover ______ when both snail species were present at high densities.

Answer 105

decreased

Question 106

In the second set of experiments with the snails Cerithidea and Batillaria, Byers found that the growth rate of Batillaria was ______ that of Cerithidea at all densities.

Answer 106

greater than

Question 107

True or false: As part of his research on the invasive snail Batillaria, Byers was able to demonstrate its competitive dominance to Cerithidea by using research plots that contained both species.

Answer 107

false