Which of the following best describes the movement of energy in an ecosystem?

• A. Energy flows in one direction, from producers to consumers to decomposers, and is eventually lost as heat.
• B. Energy cycles continuously between producers, consumers, and decomposers without any loss.
• C. Energy is stored indefinitely in the bodies of top predators.
• D. Energy is created by consumers and transferred to producers.

Answer: (A)

Verified step by step guidance

1. Understand the concept of energy flow in an ecosystem: Energy originates from the sun and is captured by producers (autotrophs) through photosynthesis. Producers convert solar energy into chemical energy stored in glucose molecules.
2. Recognize the role of consumers: Consumers (heterotrophs) obtain energy by consuming producers or other consumers. This energy transfer occurs through feeding relationships, such as herbivory, predation, or parasitism.
3. Identify the role of decomposers: Decomposers break down dead organisms and organic waste, recycling nutrients back into the ecosystem. However, energy is not recycled; it is transformed and eventually lost as heat during metabolic processes.
4. Clarify the unidirectional flow of energy: Energy flows in one direction through the ecosystem—from producers to consumers to decomposers. This flow is governed by the laws of thermodynamics, particularly the second law, which states that energy transformations are inefficient and result in heat loss.
5. Eliminate incorrect options: Energy does not cycle continuously without loss, nor is it stored indefinitely in top predators. Additionally, energy is not created by consumers; it is captured by producers from the sun. The correct description is that energy flows in one direction and is eventually lost as heat.