Why is less energy available to organisms at higher trophic levels in an ecosystem?

• A. Because higher trophic levels receive more sunlight directly
• B. Because energy is created at higher trophic levels
• C. Because producers store less energy than consumers
• D. Because energy is lost as heat during metabolic processes at each trophic level

Answer: (D)

Verified step by step guidance

1. Understand the concept of energy flow in an ecosystem: Energy enters an ecosystem through producers (autotrophs) that convert sunlight into chemical energy via photosynthesis. This energy is then transferred through various trophic levels (primary consumers, secondary consumers, etc.).
2. Recognize that energy transfer between trophic levels is inefficient: Only a small fraction of the energy (approximately 10%) is passed on to the next trophic level. The rest is lost primarily as heat during metabolic processes such as respiration, movement, and reproduction.
3. Clarify why energy is lost as heat: Organisms use energy for cellular activities, and during these processes, some energy is released as heat due to the second law of thermodynamics. This heat energy cannot be reused by organisms and is dissipated into the environment.
4. Explain why higher trophic levels have less energy available: Since energy is lost at each transfer, organisms at higher trophic levels receive less energy than those at lower levels. This limits the number of organisms that can be supported at higher trophic levels.
5. Conclude that the correct answer is based on the principle of energy loss during metabolic processes: The statement 'Because energy is lost as heat during metabolic processes at each trophic level' accurately explains why less energy is available to organisms at higher trophic levels.