Cycling

Multiple Choice

Which of the following organisms is responsible for breaking down organic material and returning nutrients to the environment?

• Autotrophs

• Saprotrophs

• Herbivores

• Carnivores

Open Ended

Why is nutrient cycling important for the survival of ecosystems?

Multiple Choice

Which of the following best describes the process by which biomass accumulates in an ecosystem?

• Autotrophs and heterotrophs grow or reproduce, increasing biomass

• Cell respiration converts carbon compounds to CO2 and water, increasing biomass

• Biomes with less sunlight accumulate biomass faster

• Productivity is only described in terms of secondary production

Open Ended

Explain the difference between gross primary production and net primary production, and why net primary production is always less than gross primary production.

Multiple Select

Which of the following statements about secondary production is/are correct?

• It represents the generation of biomass by heterotrophs and saprotrophs

• It forms from a transfer of mass through feeding

• Net secondary production accounts for biomass lost to respiration and excretion

• It is always higher than net primary production

Fill in the Blanks

The carbon cycle demonstrates the exchange of carbon between sources and

.

Multiple Choice

Based on the carbon cycle diagram, which process is responsible for transferring carbon from plants to animals?

• Feeding

• Respiration

• Photosynthesis

• Combustion

Open Ended

Describe how photosynthesis and cellular respiration contribute to carbon fluxes within ecosystems, using the diagram as a reference.

Multiple Choice

Which process leads to a decrease in atmospheric CO2 levels according to the diagram and explanation?

• Photosynthesis

• Cell respiration

• Combustion

• Decomposition

Open Ended

Explain how the formation of fossil fuels is influenced by the presence or absence of oxygen in the environment.

Multiple Select

Which of the following are products of the combustion of fossil fuels?

• Carbon dioxide

• Water

• Oxygen

• Energy

Fill in the Blanks

The Keeling curve shows an overall increase in atmospheric

concentration over time.

Open Ended

How do carbon fluxes connect the processes of photosynthesis, extinction, ecosystem sustainability, and climate change?

Multiple Choice

Which of the following statements best describes the process of nutrient cycling in ecosystems?

• Nutrients are used once by organisms and then lost from the ecosystem.

• Nutrients are constantly recycled by organisms within the ecosystem.

• Only autotrophs recycle nutrients in the ecosystem.

• Nutrients are only obtained from the soil and not returned.

Open Ended

Explain the role of saprotrophs in the nutrient cycle within ecosystems.