Ecology Ecological Succession 2

Question 1

The inhibition model of succession proposes that:

Accepted Answer

Early species resist replacement by later species until they die or are disturbed

Answer

Early species facilitate the establishment of later species

Answer

All species colonize simultaneously and compete equally

Answer

Climax communities form without any directional change

Question 2

What is the primary source of nitrogen input during early primary succession on bare rock?

Accepted Answer

Nitrogen fixation by cyanobacteria and lichens

Answer

Decomposition of animal waste

Answer

Rainfall containing dissolved nitrates

Answer

Weathering of parent rock material

Question 3

Which term describes the idea that multiple stable states can exist in an ecosystem, and a disturbance can shift the system from one state to another?

Accepted Answer

Alternative stable states

Answer

Climax theory

Answer

Monoclimax hypothesis

Answer

Relay floristics

Question 4

How does species richness typically change during early to mid-stages of succession?

Accepted Answer

It generally increases as new species colonize and habitat becomes more complex

Answer

It decreases steadily throughout succession

Answer

It remains constant from the start

Answer

It peaks immediately after disturbance then drops to zero

Question 5

Which of the following best describes the tolerance model of succession?

Accepted Answer

Later species can establish regardless of early species but are eventually out-competed by better competitors

Answer

Early species must establish before later species can colonize

Answer

Only the strongest competitor wins at every stage

Answer

Disturbance resets succession to the very beginning every time

Question 6

What role do mycorrhizal fungi play in ecosystem succession?

Accepted Answer

They facilitate plant establishment by enhancing nutrient uptake, speeding succession

Answer

They prevent plant colonization by producing allelopathic chemicals

Answer

They only appear at the climax stage of succession

Answer

They break down rock into sand, blocking soil formation

Question 7

The Intermediate Disturbance Hypothesis predicts that species diversity is highest when:

Accepted Answer

Disturbance occurs at intermediate levels

Answer

Disturbance frequency and intensity are very high

Answer

Disturbance frequency and intensity are very low

Answer

There is no disturbance at all