Chapter 19: Community Dynamics

Question 1

Temporal change in community structure is called ___.

Answer 1

succession

Question 2

The sequence of communities from grass to shrub to forest is called a ___.

Answer 2

sere

Question 3

Each of the changes throughout a sere is called a ___, and though they are points in a continuum of vegetation through time, they are often recognizable as distinct communities.

Answer 3

seral stage

Question 4

True or false: the process of succession is common only to terrestrial environments.

Answer 4

False

Question 5

These successional species are characterized by high growth rates, smaller size, a high degree of dispersal, and high rates of per capita growth.

Answer 5

Early

Question 6

These successional species are characterized by lower rates of dispersal and colonization, slower per capita growth rates, and are larger and longer lived.

Answer 6

Late

Question 7

This form of succession occurs on a site previously unoccupied by a community, like a newly exposed surface after a glacier/lava/ect. moves away.

Answer 7

Primary succession

Question 8

This form of succession occurs after a disturbance on a site that has been previously occupied, such as a forest after a big fire or an abandoned field that was once cleared for crops.

Answer 8

Secondary succession

Question 9

Grass growing on a beach is an example of ___ succession.

Answer 9

Primary

Question 10

This idea of succession was devised by Clements and says that the process of succession represents the gradual and progressive development of the community to the ultimate/climax stage.

Answer 10

Monoclimax hypothesis

Question 11

This idea of succession was devised by Egler and says that the process of succession at any site is dependent on which species gets there first and is not an orderly process. There is no competition; whoever gets there first prevents others from colonizing there.

Answer 11

Initial floristic competition

Question 12

This model of succession states that early successional species modify the environment so that it becomes more suitable for later successional species to invade and grow to maturity, so the early ones pave the way for later ones.

Answer 12

Facilitation model

Question 13

This model of succession involves strong competitive interactions, and no one species is totally superior to the other. The first species to arrive holds the site from all invaders, making the site less suitable for both early and late successional species and holding their place until they die or get damaged.

Answer 13

Inhibition model

Question 14

This model of succession says that later successional species are neither inhibited or aided by species of earlier stages, so they can invade a newly exposed site, get established, and grow just fine independent of other species there, because they can tolerate a lower level of resources.

Answer 14

Tolerance model

Question 15

This type of environmental change is a direct result of the presence and activities of organisms within the community.

Answer 15

Autogenic change

Question 16

This type of environmental change is a feature of the physical environment, governed by physical rather than biological processes.

Answer 16

Allogenic change

Question 17

Trees changing the amount of light that reaches the forest floor is an example of ___ environmental change.

Answer 17

autogenic

Question 18

A decrease in temperature with increasing depth in a lake is an example of ___ environmental change.

Answer 18

allogenic

Question 19

True or false: one feature common to all plant succession is autogenic environmental change.

Answer 19

True

Question 20

An example of autogenic change in plant succession is ___.

Answer 20

Light changing due to the canopy.

Question 21

Shade intolerant plants will dominate in ___ succession due to their fast growth rates.

Answer 21

early

Question 22

In ___ succession, shade intolerant plants will make up the canopy, but no new ones will grow; instead, shade tolerant plants will.

Answer 22

late

Question 23

Sites that are at different stages of succession are called ___.

Answer 23

chronosequences

Question 24

True or false: The processes of species colonization and replacement drive succession.

Answer 24

True

Question 25

If growth rates are slow, displacement occurs ___; if growth rates are fast, displacement occurs ___.

Answer 25

slowly; quickly

Question 26

This is a pattern of disturbance that doesn’t occur too often and also doesn’t occur too infrequently, so that species diversity is maximized.

Answer 26

Intermediate disturbance hypothesis

Question 27

True or false: Succession doesn’t occur within heterotrophic species.

Answer 27

False

Question 28

True or false: Annual fluctuations in temperature will affect secondary succession.

Answer 28

False

Question 29

True or false: Shifts in environmental changes that occur at periods longer than an organism’s life span will affect secondary succession.

Answer 29

True

Question 30

Species respond to a wide array of environmental factors that vary spatially and temporally across the landscape, and the interactions among organisms influence the nature of those responses. The product is a dynamic mosaic of communities that occupy the larger landscape.

Answer 30

Ok.