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

The inhibition model suggests that early colonizers can inhibit the establishment of later species, so succession only advances when early species are removed by disturbance or die naturally.

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

Early colonizers such as cyanobacteria and certain lichens fix atmospheric nitrogen, making it available to the ecosystem and contributing to soil development during primary succession.

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

The alternative stable states concept holds that ecosystems can exist in more than one stable configuration, and large disturbances can push a system across a threshold into a different stable state.

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

Species richness typically increases during early to mid-succession as habitat complexity grows, resources diversify, and more species can find suitable niches.

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

The tolerance model proposes that later successional species can establish early but grow slowly; they eventually replace early species because they are better competitors for resources as conditions mature.

Ecology Practice Test

Ecology Practice Test

Ecology Ecological Succession 2