Ecosystems and Food Webs

Active learning helps students visualize the invisible threads that connect organisms in an ecosystem. When students manipulate cards, role-play roles, or explore their surroundings, they move beyond abstract definitions to see firsthand how energy flows and relationships form.

• 5th Class
• Scientific Inquiry and the Natural World
• 4 activities
• 30 min–50 min

Learning Objectives

1. Classify organisms within a local ecosystem as producers, consumers (herbivore, carnivore, omnivore), or decomposers.
2. Analyze the flow of energy through a food web by tracing at least three interconnected feeding relationships.
3. Compare and contrast the definitions of habitat and niche for two different organisms in the same ecosystem.
4. Predict the cascading effects on other organisms if a keystone species is removed from a specific food web.
5. Create a visual representation of a local food web, labeling trophic levels and energy transfer pathways.

Jigsaw

⏱ 35 min·Small Groups

Card Sort: Building Local Food Webs

Provide cards with local Irish species like oak trees, rabbits, foxes, and earthworms labeled by role. In small groups, students sort cards into producers, consumers, and decomposers, then connect them with yarn to form a food web. Discuss energy flow paths.

Prepare & details

Analyze the flow of energy through a local food web.

Facilitation Tip: During the Card Sort, circulate to listen for students’ justifications when they place cards, asking clarifying questions like, 'Why did you connect the hawk to the squirrel and not the oak tree?'

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 45 min·Whole Class

Role-Play: Keystone Species Disruption

Assign roles to students as ecosystem members. One group removes the 'keystone' actor, such as a hawk, and the class acts out chain reactions on population changes. Record predictions versus outcomes on charts.

Prepare & details

Differentiate between a habitat and a niche.

Facilitation Tip: In the Role-Play activity, model neutral body language for the 'keystone species' so students focus on the ecosystem’s reaction rather than personal performance.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 50 min·Pairs

Schoolyard Habitat Survey

Students survey the school grounds for habitats like hedges or ponds, noting organisms and their niches. Sketch simple food webs based on observations and classify roles. Share findings in a class gallery walk.

Prepare & details

Predict the impact of removing a keystone species from an ecosystem.

Facilitation Tip: For the Schoolyard Habitat Survey, provide clipboards and colored pencils, and remind students to record not just what they see but also where and when they see it.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 30 min·Small Groups

Energy Flow Dominoes

Line up dominoes representing trophic levels with local examples. Topple to show energy transfer and discuss loss at each step. Groups modify setups to test keystone removal effects.

Prepare & details

Analyze the flow of energy through a local food web.

Facilitation Tip: Use Energy Flow Dominoes to physically demonstrate how energy moves through an ecosystem by having students trace the path aloud as they play.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Teaching This Topic

Teachers often introduce ecosystems by asking students to list organisms, but this overlooks the dynamic interactions at the core of the topic. Start with a simple scenario, like a fallen apple in a forest, and have students brainstorm who depends on it. Avoid rushing to definitions—instead, let students discover roles through exploration. Research shows that when students construct their own models, they retain concepts longer and transfer knowledge to new contexts.

What to Expect

Successful learning shows when students can explain how energy transfers between organisms and predict outcomes when parts of the system change. Listen for precise language about producers, consumers, and decomposers, and watch for accurate connections in their work.

Watch Out for These Misconceptions

Common Misconception

During Card Sort: Building Local Food Webs, watch for students arranging organisms in straight lines without branches.

What to Teach Instead

Prompt students to rearrange their cards by asking, 'Could one animal eat more than one type of food? Could one plant be eaten by multiple animals?' Encourage them to redraw connections until the web reflects multiple pathways.

Common Misconception

During Role-Play: Keystone Species Disruption, watch for students assuming all consumers hunt and kill.

What to Teach Instead

Have students observe peers during the role-play and list examples of herbivores or scavengers. Ask them to describe how these consumers acquire energy without hunting.

Common Misconception

During Role-Play: Keystone Species Disruption, watch for students believing one species’ loss has minimal impact.

What to Teach Instead

After the simulation, ask groups to report how the ecosystem changed when their assigned species was removed. Draw arrows on the board to show ripple effects, highlighting cause and effect.

Assessment Ideas

Quick Check

After Card Sort: Building Local Food Webs, collect students’ webs and check for at least three correct connections between producers, consumers, and decomposers in their local ecosystem.

Discussion Prompt

During Role-Play: Keystone Species Disruption, listen for students using terms like 'trophic cascade' or 'balance' when explaining the ecosystem’s reaction to the removal of a keystone species.

Exit Ticket

During Schoolyard Habitat Survey, ask students to write one observation about how human activity affects their surveyed habitat and one question they still have about the ecosystem.

Extensions & Scaffolding

• Challenge: Ask students to research a local invasive species and predict how its introduction would disrupt the food web they built in the Card Sort activity.
• Scaffolding: Provide a partially completed food web diagram for the Schoolyard Habitat Survey, with some arrows and missing organisms filled in.
• Deeper: Invite a local ecologist to discuss how human activities, such as pollution or land use changes, alter food webs in ways not covered in class.

Key Vocabulary

Producer	An organism, typically a plant or alga, that produces its own food using light energy through photosynthesis. They form the base of most food webs.
Consumer	An organism that obtains energy by feeding on other organisms. This includes herbivores, carnivores, and omnivores.
Decomposer	An organism, such as bacteria or fungi, that breaks down dead organic matter, returning essential nutrients to the ecosystem.
Food Web	A complex network of interconnected food chains showing the feeding relationships between various organisms in an ecosystem.
Habitat	The natural home or environment of an animal, plant, or other organism, providing the necessary resources for survival.
Niche	The specific role an organism plays within its ecosystem, including its interactions with biotic and abiotic factors and its use of resources.