Key Concepts: Flow of Energy in an Ecosystem

Energy Flow

Energy flows through ecosystems in one direction: from the sun → producers → consumers → decomposers.

• Producers (autotrophs): Make their own food through photosynthesis
• Consumers (heterotrophs): Obtain energy by eating other organisms
• Decomposers: Break down dead organisms and recycle nutrients

Energy Pyramid

• Only about 10% of energy transfers to the next trophic level
• The rest is lost as heat through metabolic processes
• This limits the number of trophic levels in an ecosystem