Ch 54 B

Question 1

_______ are those that are most abundant or have the highest biomass

Answer 1

Dominant species

Question 2

_______, typically introduced to a new environment by humans, may become dominant because they lack natural predators or parasites

Answer 2

Invasive species

Question 3

_______ exert strong control on a community by their ecological roles, or niches (not dominant)

Answer 3

Keystone species

Question 4

How do dominant species and keystone species differentiate

Answer 4

keystone is less abundant

Question 5

_______ (or “foundation species”) cause physical changes in the environment that affect community structure

Answer 5

Ecosystem engineers

Question 6

What are the two models regarding trophic influence

Answer 6

1) bottom-up model
2) top-down model

Question 7

What is another name for the top- down model?

Answer 7

green world hypothesis

Question 8

Explain mesopredator release

Answer 8

Where absence of top predator (wolf) leads to mesopredator abundance (coyote)

Question 9

Deliberate alteration of an ecosystem by adding or removing species, especially predators.

Answer 9

biomanipulation

Question 10

F. E. Clements, argued that plant communities had only one state of equilibrium, a _______, controlled by climate

Answer 10

climax community

Question 11

A. G. Tansley argued that _______ in abiotic conditions created many _______ stable communities within a region

Answer 11

variation; possible

Question 12

H.A. Gleason viewed communities as _______ assemblages of species with similar abiotic requirements

Answer 12

chance

Question 13

A _______ is an event that changes a community, removes organisms from it, and alters resource availability

Answer 13

disturbance

Question 14

The _______ describes communities as constantly changing after disturbance

Answer 14

nonequilibrium model

Question 15

What are the 3 types of disturbances and what do they result in?

Answer 15

1) low level: allow dominant species
2) intermediate: greatest diversity
3) high level: exclude slow-growing species

Question 16

_______ is the sequence of changes in community composition following a disturbance

Answer 16

Ecological succession

Question 17

What are the 2 types of ecological successions?

Answer 17

1) primary succession
2) secondary succession

Question 18

_______ occurs where no soil exists when succession begins

Answer 18

Primary succession

Question 19

On the glacial moraines, _______ species facilitate later arrivals by increasing soil nitrogen content

Answer 19

pioneer plant

Question 20

describe seral stages and facilitation

Answer 20

seral stage -> facilitation -> seral stage

Question 21

_______ begins in an area where soil remains after a disturbance

Answer 21

Secondary succession

Question 22

_______ and _______ are two key biogeographic factors that affect the species diversity of biological communities

Answer 22

Latitude and area

Question 23

Species richness is especially great in the _______ and generally _______ in a gradient toward the poles

Answer 23

1) tropics
2) declines

Question 24

Two main climatic factors correlated with biodiversity in terrestrial communities are _______ and _______

Answer 24

sunlight and precipitation

Question 25

_______, the evaporation of water from soil plus transpiration of water from plants

Answer 25

evapotranspiration

Question 26

_______ is the measure of potential water loss, assuming water is available

Answer 26

Potential evapotranspiration

Question 27

Evapotranspiration and potential evapotranspiration are _______ in the warm, wet conditions of the tropics

Answer 27

higher

Question 28

_______ correlates with evapotranspiration and potential evapotranspiration

Answer 28

Species richness

Question 29

The _______ quantifies the idea that, all other factors being equal, a larger geographic area has more species

Answer 29

species-area curve

Question 30

Robert MacArthur and E.O. Wilson developed a method for predicting the species diversity on islands called the _______

Answer 30

island equilibrium model

Question 31

As the number of species on an island increases, immigration _______ and extinction _______

Answer 31

decreases; increases

Question 32

On a smaller island what happens to number of species, immigration, and extinction?

Answer 32

number of species: less
immigration: less
extinction: more

Question 33

On a larger island what happens to number of species, immigration, and extinction?

Answer 33

number of species: more
immigration: more
extinction: less

Question 34

On Islands closer to the mainland what happens to immigration, and extinction?

Answer 34

immigration: more
extinction: less

Question 35

On Islands farther to the mainland what happens to immigration, and extinction?

Answer 35

immigration: less
extinction: more

Question 36

An equilibrium will be reached where the rate of _______ is equal to the rate of _______

Answer 36

immigration; extinction

Question 37

Community structure is universally affected by _______, which include disease-causing microorganisms, viruses, viroids, and prions

Answer 37

pathogens

Question 38

Pathogens can be particularly _______ in a new habitat

Answer 38

virulent