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Ecology 2227 > Chapter 16 Species Abundance and Diversity > Flashcards

Chapter 16 Species Abundance and Diversity Flashcards

1
Q

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

A

community

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2
Q

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

A

community

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3
Q

Which are components of a community’s structure?

A

the relative abundances of species

the kinds of species present

the number of species present

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4
Q

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

A

guild

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5
Q

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

A

life-form

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6
Q

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 ______.

A

guilds

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7
Q

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

A

very rare

very abundant

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8
Q

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

A

community structure

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9
Q

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

A

most species are moderately abundant

very few species are rare

few species are very common

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10
Q

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

A

guild

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11
Q

The community distribution plot of a lognormal distribution is ______.

A

bell shaped

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12
Q

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

A

life-form

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13
Q

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

A

uncommon

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14
Q

By studying plant life-forms, scientists can ______.

A

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

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15
Q

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

A

very few of the species to be very abundant

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16
Q

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

A

more species will be collected.

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17
Q

In a typical community, most species will be ______.

A

moderately abundant

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18
Q

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

A

lognormal distribution

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19
Q

Species diversity is based on which two factors?

A

the number of species in a community

the relative abundance of species in a community

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20
Q

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

A

Very few species are very rare.

Most species have moderate coverage or abundances.

Very few species are abundant

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21
Q

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

A

species richness

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22
Q

When sampling species richness in a community,

A

the common species will typically be found in small samples.

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23
Q

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

A

species evenness

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24
Q

Species diversity includes the number of ______.

A

species in a community

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25
Q

Which community would have the higher species diversity?

A

a community with 20 species with high species evenness

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26
Q

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

A

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

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27
Q

Species richness is best defined as the ___.

A

number of species in a community

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28
Q

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

A

only one species

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29
Q

Species evenness is also known as the ______.

A

relative abundance

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30
Q

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

A

a rank-abundance curve is plotted

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31
Q

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

A

the same species many times before finding additional species.

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32
Q

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

A

B has a higher species diversity.

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33
Q

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’).

A

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.

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34
Q

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

A

dominated by a few abundant species and lower species richness

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35
Q

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

A

H’ = 3.24

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36
Q

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

A

Community A has a higher habitat heterogeneity than community B.

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37
Q

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

A

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

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38
Q

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

A

foliage height

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39
Q

Which community would have the highest species diversity?

A

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

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40
Q

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

A

species evenness

species richness

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41
Q

Generally, there is a(n)

______ relationship, or correlation, between environmental complexity and species diversity.

A

positive

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42
Q

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

A

with high species evenness

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43
Q

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

A

A to have higher species diversity

44
Q

Animal diversity in terrestrial communities is positively correlated with ______.

A

plant diversity

45
Q

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

A

contained more species of warblers than other plant communities

46
Q

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

A

whether two species can coexist or exclude each other

47
Q

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

A

foliage height diversity

48
Q

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

A

silicate to phosphate is high

49
Q

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

A

higher environmental complexity

50
Q

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

A

niche

51
Q

Varying nutrient levels in a lake ______.

A

create environmental complexity leading to higher phytoplankton diversity

52
Q

High plant diversity is often correlated with ______.

A

high animal diversity

53
Q

Nutrients in lakes and terrestrial communities ______.

A

can vary over small spatial scales leading to plant habitat heterogeneity

54
Q

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

A

the ratios of essential nutrients were correct

55
Q

In tropical forest communities, plant diversity is ______.

A

very high

56
Q

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

A

silicate to phosphate is low

57
Q

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

A

physical characteristics such as moisture

their nutrient requirements

chemical characteristics such as pH

58
Q

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

A

pH

depth to the ground water

type of soil (sand or clay)

59
Q

Nutrients in a lake such as nitrates and silicates ______.

A

can vary independently of each other over small spatial scales

60
Q

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

A

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

61
Q

In abandoned agricultural fields, nutrients and moisture ______.

A

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

62
Q

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

A

many unique plant communities

63
Q

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

A

soil characteristics

64
Q

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

A

large effects on plant communities due to changes in water availability

65
Q

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

A

Plant and algae diversity decline with increasing nutrient availability

66
Q

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

A

a loss of species diversity

67
Q

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

A

high and the pH is low

68
Q

As nutrient levels increase in aquatic communities, plant ______.

A

and algae diversity decrease

69
Q

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

A

equilibrium

70
Q

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

A

They are discrete physical events.

They allow for the establishment of new individuals or colonies.

They remove individuals or biomass

71
Q

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

A

biotic factors

72
Q

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

A

decreased over time due to fertilizer use

73
Q

The intermediate disturbance hypothesis predicts that ______.

A

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

74
Q

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

A

comprised of species specialized in nitrogen uptake

75
Q

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

A

opposing forces

76
Q

Very low levels of disturbance will ______.

A

reduce species diversity because only the best competitors will survive

77
Q

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

A

a disturbance

78
Q

Abiotic forces of disturbance would include ______.

A

fire

flooding

79
Q

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

A

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

80
Q

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

A

moderate amounts of disturbance that create constantly changing conditions

81
Q

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 ______.

A

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

82
Q

Very high levels of disturbance will ______.

A

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

83
Q

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

A

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

84
Q

Sousa’s work demonstrates that disturbance ______.

A

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

85
Q

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

A

an intermediate level of disturbance that prevents competitive exclusion

86
Q

The intermediate disturbance hypothesis predicts that ______.

A

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

87
Q

In temperate grasslands, disturbances can include ______.

A

grazing

fire

trampling

88
Q

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

A

species diversity would be lower on these boulders

89
Q

Prairie dogs create disturbance in a grassland by ______.

A

grazing on the plants creating bare ground

creating burrows and depositing soil into mounds

90
Q

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

A

intermediate

91
Q

The Lotka-Volterra models predict that ______.

A

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

92
Q

Prairie dogs increase species diversity by ______.

A

creating a patchy environment with an intermediate level of disturbance

93
Q

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

A

creating bare patches of ground that facilitate colonization

94
Q

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

A

burrowing mammals

95
Q

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

A

prairie dogs

96
Q

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

A

false

97
Q

In temperate grasslands, plant diversity is highest where ______.

A

prairie dogs create a patchy environment

98
Q

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

A

allowing good colonizers and good competitors to coexist

99
Q

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

A

habitat loss

100
Q

Avian diversity has been found to be highest in ______.

A

golf courses

101
Q

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

A

increased urbanization

air and water pollution

removal of forest

102
Q

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

A

a decrease in woodland bird species

103
Q

Worldwide urbanization has led to ______.

A

a homogenization of the global biota

104
Q

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

A

can be widespread and or extreme

105
Q

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

A

an intermediate level of disturbance

106
Q

Increases in land use intensity has led to ______.

A

the spread of already widespread and non-native birds species

107
Q

As towns and cities continue to expand, ______.

A

the differences in biodiversity between regions will be decreased

Ecology 2227 (22 decks)

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