If energy transfer to the next trophic level is about 10%, which statement best explains what happens to the rest?

If energy transfer to the next trophic level is about 10%, which statement best explains what happens to the rest?

• A. The energy is lost as heat and used for metabolism or egested as waste.
• B. Energy disappears from the ecosystem.
• C. Energy is created at higher levels.
• D. Energy is stored indefinitely at higher levels.

Answer: (A)

The key idea is that energy moves through ecosystems in a one-way flow and most of it is used up by organisms for life processes, so only a small portion is available to the next level. When an organism consumes food, it uses energy for metabolism, growth, movement, and maintaining body temperature. Much of that energy is released as heat during cellular respiration, and some is excreted as waste or remains in parts that aren’t eaten or aren’t digestible. That energy is not passed on to the next trophic level and, over time, becomes heat in the environment. Energy isn’t disappearing from the ecosystem in a mysterious way, nor is it being created or stored indefinitely at higher levels. So, the rest being lost as heat and used for metabolism or waste best explains why only about 10% moves up the food chain.

The key idea is that energy moves through ecosystems in a one-way flow and most of it is used up by organisms for life processes, so only a small portion is available to the next level. When an organism consumes food, it uses energy for metabolism, growth, movement, and maintaining body temperature. Much of that energy is released as heat during cellular respiration, and some is excreted as waste or remains in parts that aren’t eaten or aren’t digestible. That energy is not passed on to the next trophic level and, over time, becomes heat in the environment. Energy isn’t disappearing from the ecosystem in a mysterious way, nor is it being created or stored indefinitely at higher levels. So, the rest being lost as heat and used for metabolism or waste best explains why only about 10% moves up the food chain.