Food Chains and Webs

Overview

In this lesson, students build simple models of food chains and then expand them into food webs. They focus on how energy moves through living things and how matter is recycled in an ecosystem.

Learning intentions

Students will be able to:

• explain that energy used by animals’ growth, motion, and warmth comes from food
• describe that energy in food originally came from the sun
• model a food chain and a food web using arrows to show energy flow
• use their models to identify how organisms are connected in an ecosystem

Success criteria

• I can draw a food chain with arrows that show energy flowing from producer to consumer.
• I can identify producers, consumers, and decomposers in my ecosystem model.
• I can explain, using my model, that energy in animals’ food came from the sun.
• I can add organisms to make a food web and explain how changes would affect other organisms.

Curriculum links

• 5-LS2-1 — Ecosystems: Interactions, Energy, and Dynamics: develop a model to describe movement of matter among plants, animals, decomposers, and the environment (linked to how decomposition returns matter).
• 5-PS3-1 — Energy: use models to describe that energy in animals’ food was once energy from the sun (food chains/webs as energy flow models).

Lesson structure (45 minutes)

1. 0–5 min · Hook with phenomenon. Teacher shows a short scenario on the board: “A forest has fewer hawks—what happens to other animals?” Students quickly think-pair-share what might change and why.

2. 5–12 min · Mini-lesson: energy + roles. Teacher leads a brief explanation: producers make food using sunlight, and consumers get energy by eating other organisms; decomposers break down dead matter and return matter to the environment. Students take 3–4 quick notes and label one example food chain (teacher provides a model).

3. 12–20 min · Direct instruction: build a food chain. Teacher demonstrates building one chain on the board: Sun → grass → grasshopper → frog → snake. Teacher emphasizes “arrows mean energy flow” and uses simple vocabulary checks (producer/consumer/decomposer). Students create their own chain on their worksheet using an assigned ecosystem card (pond, grassland, or forest).

4. 20–30 min · Small-group: expand to a food web. Teacher assigns groups of 4–5 students and gives each group 8–12 organism cards plus a template with circles connected by arrow lines. Students sort cards into producers/consumers/decomposers, then connect them with arrows to form a food web that includes at least two different food chains.

5. 30–38 min · Model critique and revise. Teacher uses “gallery walk” routines: half the groups display their web on desks/walls; the other half observes with two guiding questions posted: (1) “Do the arrows show energy flow from sun/producer to consumers?” (2) “Are decomposers included for matter recycling?” Students record one “glow” (what’s strong) and one “grow” (what to fix) on sticky notes, then switch groups once.

6. 38–44 min · Whole-class sensemaking. Teacher selects 2–3 examples and asks students to trace energy from a producer to a consumer using the arrows. Students answer with evidence from their models and practice one-sentence explanations: “Energy in a consumer’s food came from the sun because…”

7. 44–45 min · Exit ticket. Students complete a quick prompt: “Draw one food chain from your web and write one sentence explaining where the energy came from.”

Resources

• Ecosystem cards (pond/grassland/forest) with organism images or words
• Food chain and food web student recording sheets with arrow guidance
• Decomposer vs. consumer card set (to reduce confusion)
• Sticky notes or observation slips for gallery walk feedback
• Anchor chart: “Producers make food from sunlight; arrows show energy flow”
• Timer and projector/board for demonstrating one example web
• Pencils, colored pencils/markers

Assessment

• Teacher circulates during chain building and checks for correct roles (producer/consumer/decomposer) and correct arrow direction for energy flow.
• Gallery walk feedback notes reveal misconceptions (e.g., arrows pointing backward, missing energy source).
• Exit ticket: students’ ability to (1) draw a correct chain from their web and (2) explain that energy in food came from the sun.

Differentiation

• Support: Provide sentence starters for explanations (“Energy in ____’s food came from the sun because ____.”) and a word bank (producer, consumer, decomposer, energy).
• Support: Offer a partially completed web template for students who need structure (some arrows pre-drawn for the producer-to-first-consumer link).
• Extension: Challenge advanced students to include an additional organism and revise the web to show how one change (adding/removing a predator) could affect at least two other organisms.
• EAL/SEN: Use visuals on cards, allow oral rehearsal before writing for the exit ticket, and use consistent arrow-coloring (e.g., red arrows for energy flow, blue circles for producers).