Energy Flow and Ecosystem Dynamics

The lesson introduces energy transfer in ecosystems, focusing on how organisms grow and the concept of biomass. It explains the flow of energy and nutrients, highlighting the one-way flow of energy and the recycling of nutrients. The lesson covers primary productivity, distinguishing between gross and net primary productivity. It also explains food chains, food webs, and trophic level pyramids, emphasizing energy transfer efficiency. The lesson concludes with a question on the efficiency of eating plants versus animals.

What is the primary way plants gain new biomass?

• By consuming other plants

• By absorbing nutrients from the soil

• Through photosynthesis

• Through cellular respiration

What happens to energy as it moves through an ecosystem?

• It is completely recycled

• It remains constant

• It increases with each transfer

• It is lost as heat at each transfer

How is carbon recycled in an ecosystem?

• By decomposers only

• By primary consumers

• Through energy transfer

• Through photosynthesis and cellular respiration

What determines the primary productivity of an ecosystem?

• The number of consumers

• The rate of photosynthesis by producers

• The amount of sunlight

• The presence of decomposers

In a food chain, what do the arrows represent?

• The number of organisms

• The size of the organism

• The direction of energy flow

• The speed of energy transfer

What is a key feature of a food web?

• It shows a linear relationship

• It includes multiple interacting food chains

• It only includes producers and primary consumers

• It is simpler than a food chain

What does a trophic level pyramid illustrate?

• The relative numbers, biomass, or energy at different trophic levels

• The number of producers in an ecosystem

• The amount of sunlight received

• The speed of energy transfer

Why are there usually fewer organisms at higher trophic levels?

• Due to lack of sunlight

• Because they are smaller in size

• Due to the inefficiency of energy transfer

• Because they reproduce less

What is the average energy transfer efficiency between trophic levels?

• 90%

• 10%

• 25%

• 50%

What is more efficient for humans considering limited resources?

• Not eating at all

• Eating both equally

• Eating animals

• Eating plants