Deck 19: Community Dynamics

Question 1

In succession,which type of environmental change occurs when the physical environment changes,such as an increase in temperature or salinity?

A)allopatric
B)allogenic
C)autozygous
D)autogenic

Answer 1

B

Question 2

The inhibition model of succession proposes that

A)early successional species modify the environment so that it becomes more suitable for later successional species.
B)the first species to arrive make the site less suitable for later arriving species.
C)later successional species are neither inhibited nor aided by species of earlier stages.
D)competition does not occur between early successional and late successional species.

Answer 2

B

Question 3

Early successional species are referred to as ________ species.

Answer 3

pioneer

Question 4

Succession occurs in both aquatic and terrestrial environments.

Question 5

________ environmental change is a direct result of the organisms within the community.

Question 6

The number of species within a community is usually greatest when

A)no disturbance occurs.
B)a low frequency of disturbance occurs.
C)an intermediate frequency of disturbance occurs.
D)a high rate of disturbance occurs

Question 7

Succession in a community involves

A)only autotrophic species.
B)only heterotrophic species.
C)both autotrophic and heterotrophic species.
D)only detritivorous species.

Question 8

As glaciers in North America melted,formerly glaciated areas were invaded by

A)ice.
B)tundralike vegetation.
C)boreal forest,dominated by spruce and jack pine.
D)various species of trees,including spruce,white pine,oaks,and maples.

Question 9

Communities vary in composition over space but usually not in composition over time.

Question 10

The study of the distribution and abundance of ancient organisms and their relationship to the environment is referred to as ________.

Question 11

The hypothesis that moderate frequencies of disturbance result in the highest species diversity is called the ________ disturbance hypothesis.

Question 12

Which of the following is an example of an allogenic change that drives succession?

A)seasonal changes in temperature,photoperiod,and light intensity
B)increased shading of seedlings by adult trees in a forest
C)increased nitrogen availability in soil due to the presence of leguminous plants
D)reduced salinity due to surface shading by grasses in a salt marsh

Question 13

Changes in community composition and structure over time are called

A)succession.
B)stratification.
C)zonation.
D)characterization.

Question 14

An example of secondary succession is

A)grasses colonizing sand dunes.
B)lichens colonizing a rock.
C)weeds colonizing a volcanic lava flow.
D)crabgrass colonizing an abandoned wheat field.

Question 15

Succession that occurs on a site that was previously unoccupied by another community is called ________ succession.

Question 16

The ________ model of succession proposes that early successional species modify the environment so that it becomes more suitable for later successional species.

Question 17

The sequence of communities from the pioneer community to the climax community is called a(n)________.

Question 18

The ________ model of succession proposes that later successional species are neither inhibited nor aided by species of earlier stages.

Question 19

Early successional species are characterized by

A)low body growth rates.
B)large body size.
C)low degree of dispersal.
D)low per capita population growth rate.

Question 20

Groups of sites within an area that are at different stages of succession are known as

A)autosequences.
B)ecotypes.
C)clines.
D)chronosequences.

Question 21

Succession usually involves only autotrophic species such as plants.

Question 22

During plant succession,animals can quickly lose their habitat by vegetation change.

Question 23

Grasses are usually the first plant species to colonize sand dunes.

Question 24

Although community composition changes during succession,diversity rarely changes.

Question 25

The monoclimax hypothesis views succession as the gradual and progressive development of the community to the ultimate stage.

Question 26

Diversity often decreases during the later stages of succession.

Question 27

Disturbances,such as fire,can sometimes increase coexistence between species and can increase diversity.

Question 28

Community structure changes over relatively short time scales through succession,but it tends to be stable over longer geological time scales.

Question 29

In the early stages of plant succession,shade-intolerant species are often common.

Question 30

The facilitation model of succession involves strong competitive interactions among colonizing species.

Question 31

Autogenic environmental change always occurs in plant succession.

Question 32

The organismal concept of communities argues that species distributions along environmental gradients form clusters because they are interdependent.

Question 33

Light is the only environmental factor that changes during the course of succession in a community.

Question 34

Most forests in the eastern United States are more than 100 years old.

Question 35

The initial floristic composition hypothesis proposes that the process of succession at any site is dependent on which species arrive first.

Question 36

Pollen preserved within lake sediments can be used to reconstruct historical changes in the geographic ranges of plant species.

Question 37

Succession does not occur in communities subjected to periodic disturbances.