Chapter 16 Species Abundance and Diversity

Question 1

Groups of species that live in a defined area and interact with each other are termed a(n) ______.

Answer 1

community

Question 2

All of the fish, invertebrates, and algae living in the upper reaches of a stream would constitute a(n) ______.

Answer 2

community

Question 3

Which are components of a community’s structure?

Answer 3

the relative abundances of species

the kinds of species present

the number of species present

Question 4

A group of organisms that exploit resources in a similar way is termed a(n) ______.

Answer 4

guild

Question 5

Plants that are described as a vine would belong to the same ______.

Answer 5

life-form

Question 6

Some ecosystems have many thousands of species, making it difficult to study the contribution of each species to the functioning of a community. Therefore, scientists may study the effects of groups of organisms on community structure by placing them into ______.

Answer 6

guilds

Question 7

As a general rule in a community, very few species are ______.

Answer 7

very rare

very abundant

Question 8

A scientist who is studying a species’ richness as well as the relative abundances of different species in a community is determining ______.

Answer 8

community structure

Question 9

One of the most ubiquitous patterns found in communities is that ______.

Answer 9

most species are moderately abundant

very few species are rare

few species are very common

Question 10

Stream invertebrates that eat or “shred” terrestrial plant material would belong to the same ______.

Answer 10

guild

Question 11

The community distribution plot of a lognormal distribution is ______.

Answer 11

bell shaped

Question 12

The structure of a plant combined with its growth dynamics determines its ______.

Answer 12

life-form

Question 13

Species of plants with a higher percent cover (top graph) and species of forest birds with higher numbers of individuals (bottom graph) are both ______.

Answer 13

uncommon

Question 14

By studying plant life-forms, scientists can ______.

Answer 14

reduce the number of species they are studying to better understand the community structure

Question 15

Imagine a community consisting of approximately 100 species. Considering the patterns of species abundances, one would expect to find ______.

Answer 15

very few of the species to be very abundant

Question 16

A general trend when sampling is that the more you sample, the

Answer 16

more species will be collected.

Question 17

In a typical community, most species will be ______.

Answer 17

moderately abundant

Question 18

When the number of individuals in a community are plotted by the number of species, the typical result is a(n) ______.

Answer 18

lognormal distribution

Question 19

Species diversity is based on which two factors?

Answer 19

the number of species in a community

the relative abundance of species in a community

Question 20

Based on the figure illustrating lognormal distributions, what do forest birds (bottom) and desert plants (top) have in common?

Answer 20

Very few species are very rare.

Most species have moderate coverage or abundances.

Very few species are abundant

Question 21

The total number of species within a community is known as the ___.

Answer 21

species richness

Question 22

When sampling species richness in a community,

Answer 22

the common species will typically be found in small samples.

Question 23

The relative abundance of species in a community is known as the ______.

Answer 23

species evenness

Question 24

Species diversity includes the number of ______.

Answer 24

species in a community

Question 25

Which community would have the higher species diversity?

Answer 25

a community with 20 species with high species evenness

Question 26

When calculating the species diversity using the Shannon-Wiener index, the ______.

Answer 26

proportion of the ith species is multiplied by the natural log of the proportion of the ith species

Question 27

Species richness is best defined as the ___.

Answer 27

number of species in a community

Question 28

A community with an H' = 0 would have ___.

Answer 28

only one species

Question 29

Species evenness is also known as the ______.

Answer 29

relative abundance

Question 30

To view important components of a community such as evenness and richness, ___.

Answer 30

a rank-abundance curve is plotted

Question 31

In a community with very low species evenness, one would expect to encounter

Answer 31

the same species many times before finding additional species.

Question 32

If two communities had the same species richness, but the rank-abundance curve for community A was much steeper than community B, then community

Answer 32

B has a higher species diversity.

Question 33

Sampling a small community revealed the following distribution of species: species A: 100 individuals, species B: 60 individuals, species C: 40 individuals, and species D: 2 individuals. Calculate the species diversity of this community using the Shannon-Wiener index (H').

Answer 33

H' = 1.075 The number of species (S) is 4. The total number of individuals is 202 (100+60+40+2). For species A its proportion (Pi) equals 0.495 (100/202). Thus logePi = −0.7031. So the value for species A is −0.3480 (0.495 ×−0.7031). Repeat this and sum the number for all the species and then apply the negative sign in front of the equation to that sum total (−1.075) and get the answer of 1.075.

Question 34

A rank-abundance curve with a steep curve is indicative of a community ______.

Answer 34

dominated by a few abundant species and lower species richness

Question 35

Which of the following communities would have the highest species diversity?

Answer 35

H' = 3.24

Question 36

At similar latitudes, community A has many more species than community B. What is one possible explanation for this observation?

Answer 36

Community A has a higher habitat heterogeneity than community B.

Question 37

The value of a rank-abundance curve lies in its ability to ______.

Answer 37

visually portray species richness and evenness in a two-dimensional graph

Question 38

MacArthur (1958) found that warbler diversity was correlated with ______.

Answer 38

foliage height

Question 39

Which community would have the highest species diversity?

Answer 39

A community with high species richness and an abundance curve with the lowest slope.

Question 40

In forest communities, the foliage height diversity varies with ______.

Answer 40

species evenness species richness

Question 41

Generally, there is a(n) | ______ relationship, or correlation, between environmental complexity and species diversity.

Answer 41

positive

Question 42

A rank-abundance curve with shallow curve is indicative of a community ______.

Answer 42

with high species evenness

Question 43

If community A is more complex than community B, then one might expect community ______.

Answer 43

A to have higher species diversity

Question 44

Animal diversity in terrestrial communities is positively correlated with ______.

Answer 44

plant diversity

Question 45

Based on studies by MacArthur in the 1950s, communities with more complex forests ______,

Answer 45

contained more species of warblers than other plant communities

Question 46

Based on Tilman's work in 1977, the ratio of essential nutrients in communities can determine ______.

Answer 46

whether two species can coexist or exclude each other

Question 47

In forest communities, environmental complexity can be determined by ______.

Answer 47

foliage height diversity

Question 48

Tilman demonstrated that Asterionella can exclude Cyclotella when the ratio of ______.

Answer 48

silicate to phosphate is high

Question 49

Based on the figure, it can be seen that a general trend in ecological communities is for species diversity to increase with ______.

Answer 49

higher environmental complexity

Question 50

If one knows the nutrient requirements of a plant, then one can begin to define its ______.

Answer 50

niche

Question 51

Varying nutrient levels in a lake ______.

Answer 51

create environmental complexity leading to higher phytoplankton diversity

Question 52

High plant diversity is often correlated with ______.

Answer 52

high animal diversity

Question 53

Nutrients in lakes and terrestrial communities ______.

Answer 53

can vary over small spatial scales leading to plant habitat heterogeneity

Question 54

Tilman's work in 1977 showed that some diatoms can coexist when ______.

Answer 54

the ratios of essential nutrients were correct

Question 55

In tropical forest communities, plant diversity is ______.

Answer 55

very high

Question 56

Based on Tilman's 1977 work, two similar species of diatoms can coexist when the ratio of ______.

Answer 56

silicate to phosphate is low

Question 57

The niches of plants and algae can be defined by ______.

Answer 57

physical characteristics such as moisture their nutrient requirements chemical characteristics such as pH

Question 58

Which of the following are soil characteristics that are directly important to plants?

Answer 58

pH depth to the ground water type of soil (sand or clay)

Question 59

Nutrients in a lake such as nitrates and silicates ______.

Answer 59

can vary independently of each other over small spatial scales

Question 60

Studies by Jordan (1985) showed that in tropical Amazon forests, a change of elevation greater than 2 m above nearby streams would have ______.

Answer 60

sandy well-drained soils that can cause water stress in plants

Question 61

In abandoned agricultural fields, nutrients and moisture ______.

Answer 61

do not necessarily correlate with each other, creating habitat heterogeneity and leading to greater plant diversity

Question 62

In a tropical forest, a particular area may have ______.

Answer 62

many unique plant communities

Question 63

In tropical forest communities the distribution of plant communities are strongly influenced by ______.

Answer 63

soil characteristics

Question 64

In a tropical forest, changes as small as 1 m in elevation have ______.

Answer 64

large effects on plant communities due to changes in water availability

Question 65

In aquatic ecosystems, plant and algal diversity decline with ______.

Answer 65

Plant and algae diversity decline with increasing nutrient availability

Question 66

In the Park Grass Experiment, the rank-abundance curves have become steeper over time, indicating ______.

Answer 66

a loss of species diversity

Question 67

Lilleskov and his colleagues found that acid-tolerant ectomycorrhizal fungi are dominant when soil nitrogen levels are ______.

Answer 67

high and the pH is low

Question 68

As nutrient levels increase in aquatic communities, plant ______.

Answer 68

and algae diversity decrease

Question 69

When environmental conditions remain relatively the same over a time period, the community is said to be in ______.

Answer 69

equilibrium

Question 70

There are many definitions of disturbance; however, most them have which of the following in common?

Answer 70

They are discrete physical events. They allow for the establishment of new individuals or colonies. They remove individuals or biomass

Question 71

According to White and Picket, disturbances caused by disease, predation, or human activities would be classified as ______.

Answer 71

biotic factors

Question 72

Based on the figure illustrating the effect of fertilizing and plant diversity, it can be seen that plant diversity has ______.

Answer 72

decreased over time due to fertilizer use

Question 73

The intermediate disturbance hypothesis predicts that ______.

Answer 73

the highest level of species diversity is found in communities with continually changing conditions

Question 74

Under conditions of low nitrate availability, Lilleskov found that fungal communities are ______.

Answer 74

comprised of species specialized in nitrogen uptake

Question 75

In a community that is in equilibrium, the stability is maintained by ______.

Answer 75

opposing forces

Question 76

Very low levels of disturbance will ______.

Answer 76

reduce species diversity because only the best competitors will survive

Question 77

A discrete event that removes individuals or biomass and creates space for new individuals to become established is known as ______.

Answer 77

a disturbance

Question 78

Abiotic forces of disturbance would include ______.

Answer 78

fire flooding

Question 79

Species diversity is highest with an intermediate level of disturbance because ______.

Answer 79

many species can colonize a community, but disturbance will prevent any one species from becoming dominant

Question 80

Communities with the highest species diversity may be associated with ______.

Answer 80

moderate amounts of disturbance that create constantly changing conditions

Question 81

Algae and marine invertebrates living on medium-sized boulders experience an intermediate level of disturbance. From this it could be predicted that they would have ______.

Answer 81

the highest level of species diversity compared to small and larger boulders

Question 82

Very high levels of disturbance will ______.

Answer 82

reduce species diversity because few species will be able to survive the frequent and intense disturbances

Question 83

Along the intertidal zone, the most frequently disturbed boulders supported ______.

Answer 83

one or a few species that were adapted to the high levels of disturbance

Question 84

Sousa's work demonstrates that disturbance ______.

Answer 84

may allow multiple species to coexist because the disturbance prevents competitive exclusion

Question 85

The highest rate of species diversity is often associated with ______.

Answer 85

an intermediate level of disturbance that prevents competitive exclusion

Question 86

The intermediate disturbance hypothesis predicts that ______.

Answer 86

the highest level of species diversity is found in communities with continually changing conditions

Question 87

In temperate grasslands, disturbances can include ______.

Answer 87

grazing fire trampling

Question 88

Algae and marine invertebrates living on smaller boulders experience a higher frequency of disturbance; from this it could be predicted that ______.

Answer 88

species diversity would be lower on these boulders

Question 89

Prairie dogs create disturbance in a grassland by ______.

Answer 89

grazing on the plants creating bare ground creating burrows and depositing soil into mounds

Question 90

The highest rates of species diversity found among boulders in the intertidal zone were found in areas of ______ disturbance.

Answer 90

intermediate

Question 91

The Lotka-Volterra models predict that ______.

Answer 91

two species cannot coexist indefinitely when using the same resources unless disturbances occur

Question 92

Prairie dogs increase species diversity by ______.

Answer 92

creating a patchy environment with an intermediate level of disturbance

Question 93

The activities of prairie dogs help to increase plant diversity by ______.

Answer 93

creating bare patches of ground that facilitate colonization

Question 94

One of the most important and ubiquitous source of disturbance in temperate grasslands comes from ______.

Answer 94

burrowing mammals

Question 95

Perhaps the most important source of disturbance in temperate grasslands historically came from ______.

Answer 95

prairie dogs

Question 96

True or false: Human-caused disturbance such as deforestation would be considered an abiotic factor.

Answer 96

false

Question 97

In temperate grasslands, plant diversity is highest where ______.

Answer 97

prairie dogs create a patchy environment

Question 98

Prairie dogs create an intermediate level of disturbance that increases species diversity by ______.

Answer 98

allowing good colonizers and good competitors to coexist

Question 99

According the IUCN in 2007, the most serious threat to species diversity is ______.

Answer 99

habitat loss

Question 100

Avian diversity has been found to be highest in ______.

Answer 100

golf courses

Question 101

Human disturbance is widespread and comes in many forms, including ______.

Answer 101

increased urbanization air and water pollution removal of forest

Question 102

Studies in Ohio and California, showed that increases in land use intensity led to ______.

Answer 102

a decrease in woodland bird species

Question 103

Worldwide urbanization has led to ______.

Answer 103

a homogenization of the global biota

Question 104

Human disturbance is a major threat to diversity because it ______.

Answer 104

can be widespread and or extreme

Question 105

Based on several surveys by Blair in 2004, avian diversity was highest in areas with ______.

Answer 105

an intermediate level of disturbance

Question 106

Increases in land use intensity has led to ______.

Answer 106

the spread of already widespread and non-native birds species

Question 107

As towns and cities continue to expand, ______.

Answer 107

the differences in biodiversity between regions will be decreased