Energy Flow in Ecosystems: Food Webs, Decomposers & Wetland Invaders
Shared by A STEM Educator
Students will be able to construct and analyze a wetland food web, explain how energy flows from producers to consumers to decomposers, identify the role of decomposers in recycling nutrients, and predict how invasive species alter energy flow in native ecosystems.
Lesson Overview
Students trace energy flow through wetland food webs, discover the critical role of decomposers, and investigate how invasive species disrupt native energy pathways. The 10% energy rule and trophic levels anchor the high-ceiling extension.
Materials
- Species cards (wetland organisms — printed and laminated)
- Yarn or string (multiple colors)
- Tape or pushpins for attaching cards to board
- Large poster board or whiteboard space (one per group)
- Markers (multiple colors)
- 10% Energy Loss Worksheet
- Calculator (one per group)
- Decomposer observation jars (soil + leaf litter + water, prepared 1 week ahead)
- Hand lenses / magnifying glasses
- Sticky notes (two colors)
- Exit slip slips (half-sheet)
- Timer
Scaffolded Task Progression
Hint: Each arrow means 'energy came from.'
a) Which organism has the most yarn connections? Why is that important?b) Draw an arrow showing where energy goes when a frog dies. Where does it end up?c) You just removed the cattail card. List 2 organisms that immediately lost their energy source.
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