Transfer of energy and matter 1

In a stable natural ecosystem, how is the supply of nutrients and energy maintained?

• Nutrients and energy are efficiently cycled within the ecosystem.

• Energy from the Sun is cycled through the food chains, while nutrients are constantly lost.

• Nutrients are efficiently cycled within the ecosystem, while there is a constant flow of energy.

• Energy is cycled through photosynthesis and respiration, while food chains ensure that nutrients flow through the ecosystem.

Net Primary Productivity depends directly on

• Biomass and the energy produced.

• Gross primary productivity and cellular respiration

• Gross primary productivity and photosynthesis

• Energy pyramids and Biomass increase

The diagram shows flows of energy and matter in an ecosystem. What do the letters P, Q and R represent?

• A

• B

• C

• D

The pyramid of energy shows the annual gross productivity for each trophic level in the Silver Springs ecosystem in Florida. What does the pyramid show?

• Most energy is lost by the autotrophs.

• There are a larger number of herbivores than carnivores.

• The biggest loss of energy is when sunlight reflects from plants.

• The energy in the trophic levels is affected by seasonal changes.

What restricts the length of a food chain?

• The consumption of waste by detritivores.

• Energy loses between trophic levels.

• A greater biomass at the higher trophic levels

• The number of the species in the food web