Ecology Of Ecosystem Processes 2

Question 1

Which process converts atmospheric nitrogen into a form usable by plants?

Accepted Answer

Nitrogen fixation

Answer

Nitrogen fixation, performed by certain bacteria like Rhizobium, converts N₂ gas into ammonia that plants can absorb.

Question 2

What term describes the total amount of solar energy fixed by producers in an ecosystem per unit time?

Accepted Answer

Gross primary productivity

Answer

Gross primary productivity (GPP) is the total rate of photosynthetic energy fixation before any respiratory losses.

Question 3

In the phosphorus cycle, which reservoir holds the largest long-term store of phosphorus?

Accepted Answer

Sedimentary rock

Answer

Sedimentary rocks are the primary long-term reservoir of phosphorus, which is released slowly through weathering.

Question 4

What is the fate of most energy that passes through a trophic level?

Accepted Answer

It is lost as heat

Answer

Roughly 90% of energy at each trophic level is lost as metabolic heat, leaving only ~10% available to the next level.

Question 5

Which nutrient cycle is considered most tightly coupled to the carbon cycle in ecosystems?

Accepted Answer

Nitrogen cycle

Answer

The nitrogen cycle is most tightly coupled to carbon cycling because nitrogen limits primary production and is a key component of proteins and chlorophyll.

Ecology Practice Test

Ecology Practice Test

Ecology Of Ecosystem Processes 2