Food Web Builders

Overview

This is Lesson 2 of 15 in the unit Exploring Our Natural World. Students investigate how feeding relationships form food chains and food webs, then create their own example to show how energy flows through ecosystems.

Learning intentions

• Students will be able to describe producers, consumers, and predators within food chains and webs.
• Students will investigate how changes to one organism can affect others in an ecosystem.
• Students will construct a food chain and expand it into a food web using evidence from real organisms.
• Students will communicate scientific ideas clearly using diagrams and scientific vocabulary.

Success criteria

• I can identify roles in a food chain (producer, consumer, predator).
• I can construct a food chain that shows energy flow with arrows in the correct direction.
• I can build a food web that includes multiple connected food chains.
• I can explain how one change (e.g., loss of a species) could affect other organisms.

Curriculum links

• Matter and energy in ecosystems: how living things interact through feeding relationships.
• Scientific inquiry and communication: planning, creating models/representations, and explaining results.
• Connecting cause and effect in natural systems (including the impact of changes within ecosystems).
• Using appropriate science vocabulary to communicate observations and models.

Lesson structure (45 minutes)

1. 0–5 min | Hook + question Show 3–4 quick organism images on the board (e.g., grass, grasshopper, frog, snake, hawk). Ask: “Who eats whom?” Students do a quick silent think, then share one feeding relationship. Emphasize that energy moves from food to consumers.

2. 5–12 min | Mini-lesson: chain vs web Teach the difference between a food chain (one path) and a food web (many connected paths). Model one example using the board: connect arrows from food source to consumer. Briefly cover “producer” vs “consumer,” and “predator” as a type of consumer.

3. 12–18 min | Guided practice: build together As a class, choose one ecosystem (e.g., pond, forest, grassland). Provide an organism set (printed cards or list). Students work in pairs to create one food chain first, then add two more connections to form a simple food web. Teacher checks for correct arrow direction and realistic feeding links.

4. 18–30 min | Independent creation: student food chain + web Students create their own food chain and food web on paper or in notebooks. Requirements:

• Food chain: 4–6 organisms with arrows from food to eater
• Food web: include at least 8 organisms and 2+ connected chains
• Label producers/consumers (and predators if relevant)
• Add one sentence: “If one organism changes, this may affect…”

5. 30–38 min | Gallery walk + critique Students rotate through 2–3 stations or teacher-selected examples. Using a simple feedback routine, they look for: arrow direction, correct roles, and connected chains. They record one “Glow” (what’s strong) and one “Grow” (one improvement).

6. 38–43 min | Whole-class debrief: cause and effect Invite 2–3 students to share their webs. Ask targeted questions: “Which organism has many connections?” “What might happen if a producer decreases?” “Is that likely to change multiple consumers?”

7. 43–45 min | Exit ticket Students complete a short response: draw one food chain from their web and write one cause-and-effect statement (e.g., removal of one organism affects at least two others).

Resources

• Image cards or organism list for local ecosystems (pond/forest/grassland)
• Diagram paper or templates with spaces for arrows and labels
• Markers/colour pencils
• Sticky notes for Glow and Grow comments
• Teacher sample food chain and food web (large poster or slide)
• Anchor chart: “Arrow direction = energy from food to consumer”
• Sentence frames for explanation (for example: “If ___ decreases, ___ may decrease/increase because…”)
• Optional: ecosystem cards (e.g., “Grassland,” “Pond”) to support topic choice

Assessment

• Formative: teacher circulates during creation, checking arrow direction, organism roles, and connectivity.
• Formative: gallery walk Glow/Grow notes to identify common misunderstandings (e.g., reversing arrows).
• Summative for this lesson: exit ticket with a correctly drawn food chain and a clear cause-and-effect explanation.

Differentiation

• Support for ESL learners: provide sentence frames and word bank (producer, consumer, predator, arrows, energy); allow oral explanation recorded by teacher or peer.
• Support for students needing scaffolds: offer a partially completed web template with some organisms pre-placed; provide a shorter target (e.g., minimum organism counts) with clear labels first, then add complexity.
• Extension for advanced learners: require identifying a “keystone-like” organism (most connections) and predicting effects of two different changes (e.g., both a producer and a top predator).
• SEN strategies: allow alternative formats (digital drawing, cut-and-paste cards); provide checklists for requirements; reduce writing load by focusing on diagram accuracy first.
• Grouping: mix strengths in pairs for guided practice; assign roles (builder, checker, reporter) to ensure participation.