Matter and Energy in Ecosystems
Aligned to HS-LS2-3 — Next Generation Science Standards.
What this lesson teaches
Ecosystems recycle matter while energy flows through only once. Aerobic conditions use oxygen to release energy efficiently; anaerobic conditions, lacking oxygen, release far less through fermentation.
Worked example
In waterlogged mud with no oxygen, bacteria ferment organic matter and release methane, transferring far less energy than the oxygen-rich decomposition happening on dry soil.
Practice questions
- Compare the products of aerobic and anaerobic breakdown of organic matter.
- Trace one carbon atom through a food chain and back into the air.
- Explain why energy must keep entering an ecosystem but matter does not.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Materia y energía en los ecosistemas
Los ecosistemas reciclan la materia, mientras que la energía los atraviesa una sola vez. Las condiciones aeróbicas usan oxígeno para liberar energía de forma eficiente; las condiciones anaeróbicas, sin oxígeno, liberan mucha menos energía mediante la fermentación.
Ejemplo: En el lodo encharcado sin oxígeno, las bacterias fermentan la materia orgánica y liberan metano, transfiriendo mucha menos energía que la descomposición rica en oxígeno que ocurre en el suelo seco.
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