Food Webs and Energy Flow

Active learning makes abstract energy flow concepts tangible for Grade 6 students by letting them physically arrange organisms and trace energy paths. When students handle real organisms from their own ecosystem, they connect classroom science to the local environment they see every day.

• Grade 6
• Science
• 4 activities
• 20 min–45 min

Learning Objectives

1. Classify organisms within a given food web as producers, primary consumers, secondary consumers, or decomposers.
2. Explain the transfer of energy from one trophic level to the next, identifying the approximate percentage of energy transferred.
3. Create a model of a local Ontario ecosystem's food web, illustrating the flow of energy.
4. Predict the cascading effects on a food web if the population of a specific organism is significantly altered.

Concept Mapping

⏱ 30 min·Pairs

Card Sort: Local Food Web Builder

Provide cards with local Ontario organisms, arrows for energy flow, and labels for trophic levels. In pairs, students sort and connect cards into a food web on large paper, justifying placements with research notes. End with labeling producers, consumers, and decomposers.

Prepare & details

Construct a food web for a local ecosystem, identifying producers, consumers, and decomposers.

Facilitation Tip: For the Card Sort, provide real Ontario organism cards and have students physically arrange them on large paper before drawing arrows.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Stations Rotation

⏱ 45 min·Small Groups

Stations Rotation: Energy Transfer Models

Set up stations with pyramid diagrams: one for numbers, biomass, and energy. Small groups add cutouts of organisms to each pyramid, calculating 10 percent energy loss between levels. Rotate and compare results.

Prepare & details

Explain how energy is transferred between trophic levels in an ecosystem.

Facilitation Tip: During Station Rotation, place clear energy transfer models at each station with visible losses marked (e.g., heat symbols) to reinforce dissipation.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Simulation Game

⏱ 35 min·Whole Class

Simulation Game: Disruption Role-Play

Assign whole class roles as organisms in a food web. Use balls of yarn to show connections. Remove primary consumers and observe chain reactions as predators 'starve' by dropping yarn. Discuss predictions versus outcomes.

Prepare & details

Predict the impact on a food web if a primary consumer population significantly decreases.

Facilitation Tip: In the Disruption Role-Play, assign specific species to students so they experience firsthand how removals ripple through the web.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Concept Mapping

⏱ 20 min·Individual

Individual: Prediction Journal

Students draw a food web, then predict and sketch changes if a species decreases. Use before-and-after comparisons with annotations on energy flow impacts.

Prepare & details

Construct a food web for a local ecosystem, identifying producers, consumers, and decomposers.

Facilitation Tip: For the Prediction Journal, require students to sketch energy paths AND write one sentence explaining why energy is lost at each transfer.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Teaching This Topic

Teachers should start with local, familiar ecosystems to build relevance before introducing abstract trophic levels. Avoid rushing to the textbook definition of energy pyramids; instead, let students discover the 10% rule through repeated modeling. Research shows that when students physically manipulate energy flow models, their retention of transfer principles improves by 25-30% compared to passive diagram analysis.

What to Expect

Successful learning looks like students accurately labeling trophic levels, explaining why energy decreases between levels, and predicting how ecosystem disruptions cascade through food webs. Group work should show clear cause-and-effect reasoning about feeding relationships.

Watch Out for These Misconceptions

Common Misconception

During Card Sort: Local Food Web Builder, watch for students who arrange organisms in a circle to show energy cycling like the water cycle.

What to Teach Instead

Ask students to trace an energy path from the sun to the top predator using yarn, then point out that the yarn ends at the predator with no return to the sun, making energy flow visible.

Common Misconception

During Station Rotation: Energy Transfer Models, watch for students who assume any consumer can eat any organism at lower levels.

What to Teach Instead

Have students check labeled arrows on their station models to see that specific predators only connect to their actual prey species, reinforcing trophic specificity through the physical arrangement.

Common Misconception

During Simulation: Disruption Role-Play, watch for students who believe removing one species has minimal impact on the ecosystem.

What to Teach Instead

After each removal, ask the affected species to step aside physically, then have the group observe and record which other organisms lose connections or food sources, making ripple effects undeniable.

Assessment Ideas

Quick Check

After Card Sort: Local Food Web Builder, collect student food webs and check that all arrows point in the correct energy flow direction and that each organism is labeled with its trophic level.

Discussion Prompt

During Simulation: Disruption Role-Play, circulate and listen for groups that correctly identify secondary and tertiary effects of species removal, such as how decomposer populations increase due to more dead organic matter.

Exit Ticket

After Prediction Journal, collect journals and check that students define producers accurately and give Ontario examples like sugar maple or white pine, and that they explain energy loss using the 10% rule with reference to their drawn models.

Extensions & Scaffolding

• Challenge early finishers to research and add invasive species to their food web, predicting how these changes affect local producers and consumers.
• Scaffolding for struggling students: Provide pre-drawn food web templates with some arrows missing, asking them to complete the energy paths using organism cards.
• Deeper exploration: Have students calculate the total biomass at each trophic level for their ecosystem, using local biomass data from Ontario government sources.

Key Vocabulary

Producer	An organism, typically a plant or alga, that produces its own food using light, water, carbon dioxide, or other chemicals. They form the base of most food webs.
Consumer	An organism that obtains energy by feeding on other organisms. Consumers are categorized as primary (herbivores), secondary (carnivores or omnivores), and tertiary.
Decomposer	An organism, such as bacteria or fungi, that breaks down dead organic material, returning essential nutrients to the ecosystem.
Trophic Level	The position an organism occupies in a food chain or food web. Each level represents a step in the transfer of energy.
Food Web	A complex network of interconnected food chains showing the feeding relationships and energy flow within an ecosystem.