Why is the transfer of energy in a food chain usually only about 10 percent efficient?

• A. Energy is destroyed during the transfer between trophic levels.
• B. Most of the energy is lost as heat due to metabolic processes such as respiration.
• C. Producers absorb only 10 percent of the sunlight that reaches them.
• D. All energy is stored in the bodies of organisms and passed on to the next trophic level.

Answer: (B)

Verified step by step guidance

1. Understand the concept of energy transfer in a food chain: Energy flows through trophic levels in an ecosystem, starting with producers (plants) that capture sunlight through photosynthesis, and then moving to consumers (herbivores, carnivores, etc.).
2. Recognize the inefficiency of energy transfer: Only about 10% of the energy at one trophic level is passed on to the next level. This is because most of the energy is used by organisms for metabolic processes such as respiration, movement, and reproduction, and is eventually lost as heat.
3. Clarify why energy is lost as heat: Metabolic processes, such as cellular respiration, convert chemical energy from food into usable energy (ATP). However, during these processes, a significant portion of energy is released as heat, which cannot be utilized by the next trophic level.
4. Address the misconception about sunlight absorption: Producers absorb only a fraction of the sunlight that reaches them, but this is unrelated to the 10% energy transfer efficiency between trophic levels. The 10% rule applies to energy transfer between organisms, not sunlight absorption.
5. Explain why energy is not fully stored in organisms: Energy is not entirely stored in the bodies of organisms because it is constantly being used for life processes. Only a small portion of the energy consumed is stored in tissues and available for the next trophic level.