Deck 18: Community Dynamics

Question 1

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.

Answer 1

D

Question 2

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

Answer 2

intermediate

Question 3

Overgrazing of kelp forests and their subsequent regrowth is

A)primary succession.
B)chronosequence.
C)secondary succession.
D)allogenic change.

Answer 3

C

Question 4

The organismal view of communities is a ________ concept,while the continuum view of communities is a ________ concept.

Question 5

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

Question 6

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

Question 7

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

Question 8

Which of the following are late successional species?

A)trees
B)grass
C)weeds
D)forbs

Question 9

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

Question 10

According to the figure,which species is considered a pioneer species?

A)Ulva spp.
B)Gigartina canaliculata
C)Gigartina coulteri
D)Gigartina leptorhynchos

Question 11

Early successional species are referred to as ________ species.

Question 12

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

Question 13

Changes in community composition and structure over time are called

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

Question 14

Beach grass colonizing newly formed sand dunes is

A)primary succession.
B)secondary succession.
C)chronosequence.
D)autogenic change.

Question 15

The Hubbard Brook Experimental Forest is best known for what occurring after forest clearing?

A)primary succession
B)sere
C)secondary succession
D)final succession

Question 16

Habitats in which resources are limited favor ________ species that allocate resources to maintenance.

Question 17

Chronosequences are useful because one can

A)view several taxa in one sere.
B)view several seres in one region.
C)measure the impacts of disturbance.
D)count the number of trees in one sere.

Question 18

Which is an example of secondary succession?

A)Beach grasses colonize a newly formed sand dune.
B)Retreating glaciers leave alluvial soils for cottonwood trees to colonize.
C)A shift in river flow introduces sediment to a rocky area.
D)A farmer allows an agricultural field to return to native grassland.

Question 19

Early successional species are characterized by

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

Question 20

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

Question 21

As succession proceeds,what occurs with animals living in the habitat?

A)Animals adapt to the new vegetation.
B)Animals leave as their habitat disappears.
C)New animal species evolve in response to vegetation.
D)Animal species diversity continually decreases.

Question 22

Succession in a community involves

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

Question 23

Which of the following is a characteristic of a late successional plant species?

A)high photosynthetic rates
B)high stomatal conductance
C)high efficiency at low light
D)high acclimation potential

Question 24

Who developed the monoclimax hypothesis?

A)Joseph Connell
B)Frank Egler
C)Henry Cowles
D)Frederick Clements

Question 25

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 26

According to Grime,which strategy is followed by stress-tolerant species?

A)C strategy
B)S strategy
C)R strategy
D)T strategy

Question 27

Which of the following best describes diversity change through time in succession?

A)steady increase over time
B)steady decrease over time
C)starting and ending with high diversity
D)highest diversity in middle successional stages

Question 28

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 29

Which of the following is considered a ruderal species?

A)one that is a strong competitor
B)one that colonizes well
C)one that is highly stress tolerant
D)one that requires abundant resources

Question 30

What is the resource-ratio hypothesis?

A)Late successional species are not affected by species of previous stages.
B)There are three strategies in terms of resource use by plants.
C)There is a pattern of changing allocation of carbon to aboveground and belowground tissues.
D)The process of succession is determined by who gets there first.

Question 31

Which backyard would you predict to have the greatest diversity of birds?

A)one with newly planted seedlings
B)one with 5- to 10-year-old trees
C)one with 25- to 50-year-old trees
D)one with 60- to 100-year-old trees

Question 32

For processes such as those in the figure that can take thousands of years,how can we know that succession can occur in this way?

A)via carbon dating
B)via chronosequences
C)via long-term studies
D)via the phytoplankton community

Question 33

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

Question 34

The intermediate disturbance hypothesis predicts

A)low disturbance will increase diversity.
B)intermediate disturbance will increase diversity.
C)intermediate disturbance will decrease diversity.
D)high disturbance will increase diversity.

Question 35

What is the timescale for succession to occur?

A)years
B)decades
C)millennia
D)All of the above are suitable timeframes.

Question 36

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.

Question 37

What does this figure suggest is responsible for increasing species diversity?

A)time alone
B)increasing leaf litter
C)decreasing leaf litter
D)increase in agriculture

Question 38

Which of the following is an autogenic change?

A)decrease in water depth due to seismic shift
B)increase in salinity due to tides
C)global climate change due to increased CO₂ emissions
D)decreased light due to canopy cover

Question 39

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 40

An old pine tree in the front yard is beginning to die as the neighborhood deciduous trees have grown.Why might this be?

A)Deciduous trees have depleted the soil of nutrients.
B)The pine tree is shade intolerant.
C)The pine tree has depleted the soil of nutrients.
D)Deciduous trees are shade intolerant.

Question 41

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

Question 42

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

Question 43

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

Question 44

Autogenic environmental change always occurs in plant succession.

Question 45

Recent data indicate what regarding forests in eastern North America?

A)a steady increase in forest since the late 1800s
B)no change over the past 200 years
C)no change in the past 50 years
D)a decline in forested area in the past 50 years

Question 46

Although community composition changes during succession,diversity rarely changes.

Question 47

Succession occurs in both aquatic and terrestrial environments.

Question 48

Diversity often decreases during the later stages of succession.

Question 49

Succession usually involves only autotrophic species such as plants.

Question 50

Why do we think that the forest communities of eastern North America have changed dramatically over the past 18,000 years?

A)Glacial retreat exposed land for primary succession that long ago.
B)Large fires exposed land for secondary succession that long ago.
C)Successional changes are typically very rapid and all communities change at this speed.
D)Pollen evolved at this time.

Question 51

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

Question 52

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

Question 53

Which is the more correct view of communities?

A)Gleason's individualistic concept
B)Clement's organismal concept
C)It depends upon the perspective.
D)Both views were completely wrong.

Question 54

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

Question 55

What can paleoecologists utilize to assess which tree species existed in an area?

A)climate models
B)soil types
C)DNA from current trees
D)ancient pollen

Question 56

Succession does not occur in communities subjected to periodic disturbances.

Question 57

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 58

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

Question 59

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

Question 60

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

Question 61

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

Question 62

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

Question 63

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

Question 64

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