CLEP Biology Ecosystems and Energy Flow 5

Question 1

Which ecological concept explains why most food chains rarely exceed 4–5 trophic levels?

Accepted Answer

Energy loss at each trophic transfer limits available energy

Answer

Because only about 10% of energy passes from one trophic level to the next, energy available to high-order consumers becomes too small to support viable populations beyond 4–5 levels.

Question 2

In the hydrological (water) cycle, which process returns the greatest volume of water vapor to the atmosphere from terrestrial ecosystems?

Accepted Answer

Transpiration by plants combined with evaporation (evapotranspiration)

Answer

Evapotranspiration, the combined loss through soil evaporation and plant transpiration, accounts for the majority of water returning to the atmosphere over land.

Question 3

Which statement accurately describes the relationship between biodiversity and ecosystem stability?

Accepted Answer

Ecosystems with greater species richness tend to be more resistant to disturbance

Answer

Greater species richness provides functional redundancy — if one species is lost, others can fill similar ecological roles, maintaining ecosystem function.

Question 4

Secondary productivity in an ecosystem refers to the rate at which:

Accepted Answer

Consumers convert ingested food energy into new consumer biomass

Answer

Secondary productivity measures the rate at which heterotrophic consumers build new biomass from assimilated energy, after subtracting their own respiration losses.

Question 5

Which abiotic factor most strongly determines the distribution and type of terrestrial biome found at a given location?

Accepted Answer

Annual temperature and precipitation

Answer

Annual patterns of temperature and precipitation are the primary abiotic drivers that determine whether a location supports tundra, grassland, forest, desert, or another biome type.

CLEP Practice Test

CLEP Practice Test

CLEP Biology Ecosystems and Energy Flow 5