Deck 17: Community Structure

Question 1

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

Answer 1

hypolimnion

Question 2

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

Answer 2

abundance

Question 3

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.

Answer 3

individualistic or continuum

Question 4

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

Question 5

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

Question 6

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

Question 7

A(n)________ is a type of community with relatively consistent species composition; a uniform,general appearance; and a distribution that is characteristic of a particular habitat.

Question 8

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

Question 9

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

Question 10

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

Question 11

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

Question 12

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

Question 13

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

Question 14

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

Question 15

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

Question 16

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.

Question 17

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

Question 18

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

Question 19

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 20

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 21

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 22

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 23

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

Question 24

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

Question 25

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 26

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

Question 27

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

Question 28

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

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

Question 29

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 30

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 31

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 32

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 33

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 34

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

Question 35

A food web is more complicated than a food chain.

Question 36

Within a food web,herbivores are considered to be

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

Question 37

Dominance is the converse or opposite of diversity.

Question 38

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 39

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

Question 40

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 41

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

Question 42

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

Question 43

Every community has an associated vertical structure.

Question 44

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

Question 45

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

Question 46

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

Question 47

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

Question 48

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 49

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

Question 50

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