Deck 17: Community Dynamics

Question 1

Cowle's sand dune study utilized the concept of

A)secondary succession.
B)toposequence.
C)chronosequence.
D)fragmentation.

Answer 1

B

Question 2

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

Answer 2

Autogenic

Question 3

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

Answer 3

intermediate disturbance

Question 4

Succession that occurs on a site not previously occupied by a community is called ________ succession.

A)basic
B)primary
C)initial
D)secondary

Question 5

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

Question 6

Changes in community composition and structure over time are called

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

Question 7

Define the intermediate disturbance hypothesis.

Question 8

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 9

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

Question 10

High growth rates, smaller size, high degree of dispersal, and high rates of population growth are typical of ________ successional species.

Question 11

In primary succession, only ________ species function as pioneers.

A)invertebrate
B)plant
C)generalist
D)stress-tolerant

Question 12

Within an area, a group of sites that are at different stages of succession is known as a ________.

Question 13

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 14

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

Question 15

________ environmental change is due to a change in the physical environment that is independent of the species in the community.

Question 16

The ________ model proposes that later successional species are neither inhibited nor aided by species of earlier stages, and they establish themselves independently of species that precede or follow them.

A)facilitation
B)inhibition
C)tolerance
D)seral

Question 17

________ is a temporal change in community composition and structure.

Question 18

Briefly describe the cycle of succession in marshes.

Question 19

Define the term chronosequence. Under what conditions is this method of study most valid?

Question 20

Explain how chance plays a minimal role in determining species composition in early primary succession.

Question 21

During the early stages of succession, diversity typically

A)increases.
B)decreases.
C)stays the same.
D)varies frequently.

Question 22

Diversity often decreases during the later stages of succession.

Question 23

The view of communities as species responding independently to the underlying features of the environment, rather than being interdependent, is referred to as the ________ concept of communities.

A)autogenic
B)organismal
C)individualistic, or continuum
D)allogenic

Question 24

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

Question 25

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

Question 26

Egler's initial floristic composition hypothesis posits that the process of succession at any site is dependent on which species get there first.

Question 27

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

Question 28

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

Question 29

Early successional species are usually long-lived and slow-growing.

Question 30

The colonization of sand dunes by grasses is an example of secondary succession.

Question 31

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 32

Changes in temperature and precipitation are examples of ________ changes.

A)autogenic
B)allogenic
C)unpredictable
D)inconsequential

Question 33

Canada contains approximately ________ of the world's old growth forests.

A)1/10
B)1/5
C)1/4
D)1/3

Question 34

Primary succession occurs when the community at a site is disturbed and then replaced by a different community.

Question 35

Although community composition changes during succession, diversity rarely changes.

Question 36

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

Question 37

The inhibition model of succession involves strong competitive interactions with the first species to arrive maintaining its position until it is weakened or dies, after which it yields space to another species.

Question 38

In succession, ________ changes occur as a result of the activity of the organisms present.

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

Question 39

Succession usually involves only autotrophic species such as plants.

Question 40

Succession involves

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

Question 41

Outline and describe the three proposed mechanisms used in early succession.

Question 42

Using a specific example, discuss the ecological differences between early successional species and late successional species within a sere.

Question 43

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

Question 44

Explain how a chronosequence can be used to understand succession.

Question 45

Explain the difference between the organismal concept of communities and the individualistic continuum concept. Which do you think most accurately describes real communities and why?

Question 46

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

Question 47

Using specific examples for each, describe the differences between autogenic and allogenic environmental changes that drive succession.

Question 48

Using specific examples for each, explain the differences between primary and secondary succession.

Question 49

Describe the process of succession of heterotrophic organisms associated with decomposition of a fallen tree.

Question 50

A good example of succession involving heterotrophic species occurs when dead organic matter is decomposed over long periods of time.

Question 51

Community structure changes over relatively short time scales through succession, but generally is stable over longer geological time scales.

Question 52

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

Question 53

Define Old Growth and outline the strengths and weakness of the Canadian approach to these types of forests.