Which statement most accurately describes how matter and energy are used in ecosystems?

• A. Matter flows through ecosystems and is lost as heat, while energy is recycled.
• B. Both energy and matter are recycled indefinitely within ecosystems.
• C. Neither energy nor matter is recycled; both are lost from ecosystems.
• D. Energy flows through ecosystems and is eventually lost as heat, while matter is recycled within ecosystems.

Answer: (D)

Verified step by step guidance

1. Understand the distinction between matter and energy in ecosystems: Matter refers to physical substances (e.g., carbon, nitrogen, water), while energy refers to the ability to do work, often originating from sunlight in ecosystems.
2. Recognize that energy flows through ecosystems: Energy enters ecosystems primarily through photosynthesis, where sunlight is converted into chemical energy by producers. This energy is then transferred through trophic levels (producers, consumers, decomposers).
3. Note that energy is not recycled: As energy moves through trophic levels, some of it is lost as heat due to metabolic processes (e.g., cellular respiration). This loss of energy as heat means energy cannot be recycled within ecosystems.
4. Understand that matter is recycled: Matter, such as nutrients and elements (e.g., carbon, nitrogen, phosphorus), cycles through ecosystems via biogeochemical cycles. These cycles involve processes like decomposition, assimilation, and nutrient uptake by organisms.
5. Conclude that the correct description is: Energy flows through ecosystems and is eventually lost as heat, while matter is recycled within ecosystems through biogeochemical cycles.