TCE Biology — Level 3
Ecosystem Energy Flow — Flashcards & Quiz
Ecosystem energy flow describes how energy moves from the sun through producers to various consumer levels and is lost as heat at each transfer. TCE Biology Level 3 expects you to construct food chains and webs, calculate energy transfer efficiency between trophic levels, and explain why ecological pyramids narrow toward the top.
Sample Flashcards
Q1: Explain why energy flow in an ecosystem is described as one-way and non-cyclical.
Energy enters ecosystems as sunlight, is converted to chemical energy by photosynthesis, and passes through trophic levels. At each level, most energy (~90%) is lost as heat through cellular respiration and is unavailable to higher levels. Energy cannot be recycled — it must be continuously supplied by the sun. This contrasts with nutrients, which are recycled.
Sample Quiz Questions
Q1: Energy in an ecosystem is recycled between trophic levels by decomposers.
Answer: FALSE
NUTRIENTS are recycled by decomposers, but ENERGY flows one way and is ultimately lost as heat. Energy cannot be recycled — it must be continuously supplied by the sun through photosynthesis.
Last updated: March 2026 · 1 flashcards · 1 quiz questions