Deck 16: Community Structure

Question 1

Within a community,a group of species that carries out similar functions or exploits the same resource is called a(n)________.

Answer 1

guild

Question 2

During the summer,the bottom,cold layer of dense water in a well-stratified lake is called the ________.

Answer 2

hypolimnion

Question 3

When an ecologist compares the diversity of different communities by counting the number of species within each community,the measure of diversity being used is called

A)species evenness.
B)species diversity.
C)species richness.
D)relative abundance.

Answer 3

C

Question 4

A straight-line diagram illustrating the flow of food energy from prey to predator is referred to as a food ________.

Question 5

In a food web diagram,________ species feed on no other species but are fed upon by others.

Question 6

A species that has a disproportionate impact on a community,relative to its abundance,is called a(n)________ species.

Question 7

In a forest community,the layer containing tall shrubs,small trees,and young trees is called the ________.

Question 8

In a food web diagram,groups of species that derive food energy from a similar source are called ________ levels.

Question 9

A ________ diagram plots each species in a community,beginning with the most abundant and ending with the least abundant,along the x-axis,with the corresponding value of relative abundance on the y-axis.

Question 10

________ index (D)represents the probability that two individuals randomly selected from a sample will belong to the same species.

Question 11

Changes in the physical and biological structures of communities as one moves across the landscape are referred to as ________.

Question 12

When a single or a few species are most prevalent in a community,the species are called ________.

Question 13

The simplest measure of community structure is a count of the number of species present and is referred to as species ________.

Question 14

The percentage of individuals in a community that belong to one species is called the relative ________ of that species.

Question 15

Communities with low evenness will have rank-abundance curves

A)that are very steep.
B)that are 1:1.
C)that are very shallow.
D)that are flat.

Question 16

In a forest community,the upper layer is called the ________.

Question 17

The view developed by H.A.Gleason that communities result from similarities in species' requirements and tolerances for environmental factors is referred to as the ________ concept of communities.

Question 18

In aquatic habitats,the bottom zone where decomposition is most active is referred to as the ________ zone.

Question 19

In a rank-abundance curve comparing two communities,the community with the greater species richness is characterized by a

A)lesser length of the curve and a more gradual slope.
B)lesser length of the curve and a steeper slope.
C)greater length of the curve and a more gradual slope.
D)greater length of the curve and a steeper slope.

Question 20

In aquatic habitats,the upper zone of water where the availability of light supports photosynthesis by phytoplankton is called the ________ zone.

Question 21

The total number of observed links in the food web divided by the total number of species is the

A)connectance.
B)Simpson index.
C)linkage density.
D)mean chain length.

Question 22

A species that has massive effects on an ecosystem but in proportion to its abundance is a

A)keystone species.
B)basal species.
C)dominant species.
D)top predator.

Question 23

What might be a result of hunting sea otters to extinction for their fur?

A)loss of killer whales
B)loss of sea urchins
C)loss of kelp beds
D)loss of barnacles

Question 24

Which of the following is considered a guild?

A)mammals
B)coniferous forest
C)top predators
D)insect-feeding birds

Question 25

In a forest community,the layer in which most photosynthesis occurs is the

A)canopy.
B)midstory.
C)understory.
D)forest floor.

Question 26

In the following community,which serves as the keystone species?

A)killer whales
B)sea otters
C)sea urchins
D)kelp bed

Question 27

The relative abundance of a tree with 100 individuals in a community of 1000 would be

A)10.
B)1)
C)0)1.
D)100.

Question 28

Which statement best describes a keystone species?

A)a rare or uncommon species that has a strong effect on its community
B)an abundant species that may or may not affect other species
C)a species that takes up a great deal of space in a community
D)a common species that has a strong effect on its community

Question 29

The species at the top of a food web

A)do not prey on other species and are not subject to predation.
B)do not prey on other species and are subject to predation.
C)prey on other species and are not subject to predation.
D)prey on other species and are subject to predation.

Question 30

The layer of a forest in which decomposition takes place and mineral nutrients are released for reuse by plants is called the

A)canopy.
B)understory.
C)herb layer.
D)forest floor.

Question 31

If you get a Simpson's index of 1,this means

A)there is only one species in the community.
B)all species are in equal proportions.
C)the calculation is incorrect as this is theoretically impossible.
D)the Shannon index will equal 0.

Question 32

Which of the following values of evenness represents a completely even distribution?

A)100
B)10
C)1
D)0

Question 33

Which of the following has the highest species richness? A community with

A)34 species of high evenness.
B)36 species with very low evenness.
C)35 species of high evenness.
D)33 species of low evenness.

Question 34

Which is the most dominant species?

A)largest in number
B)highest in relative abundance
C)most relative biomass
D)All of the above can indicate dominance.

Question 35

Which description is true for most communities?

A)All species have approximately equal abundances.
B)All species are rare.
C)All species are common.
D)A few species are common and the remainder are rare.

Question 36

Dominant species tend to be more abundant than other species because they

A)prey upon or parasitize other species.
B)outcompete other species.
C)are preyed upon less than other species.
D)reproduce more rapidly than other species.

Question 37

The garter snake in this diagram is an example of a(n)

A)top predator.
B)basal species.
C)herbivore.
D)intermediate species.

Question 38

Which of the following groups of species represents a guild?

A)species of birds that feed on nectar
B)species of plants that use the C₃ pathway of photosynthesis
C)species of plants that tolerate shade
D)species of plants or animals that are iteroparous

Question 39

Within a food web,herbivores are considered to be

A)basal species.
B)intermediate species.
C)top predators.
D)represented at any level.

Question 40

The greater the number of links in a food chain,the higher the

A)species diversity.
B)number of top predators.
C)connectance.
D)mean chain length.

Question 41

In which of the following zones would you most likely expect to find flounders (a type of fish)?

A)subtidal
B)intertidal
C)supratidal
D)salt meadow

Question 42

Which of the following physical structures would a lake possess?

A)photic layer
B)canopy
C)herb layer
D)keystone species

Question 43

Among the array of species that make up a community,not all are equally abundant.

Question 44

A food web is more complicated than a food chain.

Question 45

The form and structure of terrestrial communities are defined more by the plants than the animals present.

Question 46

An organismic concept of communities was developed by

A)Gleason.
B)Simpson.
C)Shannon.
D)Clements.

Question 47

The goal of restoration ecology is to

A)create the most functional ecosystem.
B)improve productivity in an ecosystem.
C)return the community to its pre-disturbance condition.
D)restore the use of ecosystem services.

Question 48

In a well-stratified lake in summer,the subsurface layer of water,which is characterized by a steep and rapid decline in temperature with depth,is called the

A)epilimnion.
B)metalimnion.
C)hypolimnion.
D)benthic zone.

Question 49

A key limitation of the coefficient of community is that it lacks the ability to

A)compare relative abundances of each species.
B)calculate the similarity between two communities.
C)know the number of species common between communities.
D)compute a percent similarity value.

Question 50

The species within a guild are unlikely to interact with one another.

Question 51

The removal of a keystone species from a community typically results in an increase of diversity.

Question 52

Who was Aldo Leopold?

A)a conservationist
B)a statistician
C)a hunter
D)a marine biologist

Question 53

In a sandy beach community,ghost crabs and beach flies occur within

A)the supratidal zone.
B)the intertidal zone.
C)the subtidal zone.
D)any tidal zone.

Question 54

Which elevational gradient has the most species?

A)1920-2140 m
B)1680-1920 m
C)1370-1680 m
D)cannot tell from figure

Question 55

An ecologist samples the abundance of various species along an environmental gradient and fails to find clusters of species.Instead,peaks of abundance of dominant species are merely randomly spaced segments along a continuum.This distribution of species supports the

A)unified concept of a community.
B)organismic concept of a community.
C)individualistic or continuum concept of a community.
D)successional concept of a community.

Question 56

The species within a community interact with one another either directly or indirectly.

Question 57

Zonation within a community is typically the result of differences in the

A)patterns of predation among species within a community.
B)rates of reproduction among species within a community.
C)patterns of competition among species within a community.
D)physical characteristics of the environment across a spatial gradient.

Question 58

Most communities have many common species and a few rare species.

Question 59

Dominance is the converse or opposite of diversity.

Question 60

Which score suggests a high degree of community similarity?

A)0)9
B)9
C)90
D)900

Question 61

In a well-stratified lake,the thermocline refers to a steep and rapid decline in temperature relative to the waters above and below.

Question 62

Species composition does not usually differ much within a local area,such as between a hilltop and a stream bottomland.

Question 63

The organismic concept views communities as clusters of species associating together as an interacting,integrated component.

Question 64

The characteristics of a community are generally not dependent on the spatial scale at which the community is examined because communities are tightly integrated groups of species.

Question 65

The aphotic zone of a lake is inhabited primarily by phytoplankton.

Question 66

If a forest canopy is dense and closed,the understory and shrub layers tend to be well developed.

Question 67

Every community has an associated vertical structure.

Question 68

Some aquatic communities are defined by physical features of the abiotic environment rather than by the dominant organisms.

Question 69

Ecologists use a variety of useful sampling and statistical techniques for delineating and classifying communities.

Question 70

The boundaries between communities are usually sharply defined and easily discerned.