Food Chains and Ecosystems

Overview

Unit: Exploring Environment and Adaptation
Lesson: 6 of 8
Duration: 60 minutes
Class size: 30 students
Year group: Year 7
National Curriculum Links:

• Science Programmes of Study: Biology
• Key stage 3 (relevant objectives applicable to Year 7 foundational knowledge)
• Describe the functions of different parts of plants and animals and how these relate to their roles within habitats (NC Key Stage 3, Biology)
• Understand how energy is transferred in food chains, beginning with producers (plants) (NC Key Stage 3, Biology)
• Explore how organisms depend on each other and their environment to survive (NC Key Stage 3, Biology)

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Learning Objectives

By the end of the lesson, students will:

• Define and differentiate producers, consumers (primary, secondary, tertiary), and decomposers within food chains.
• Explain the flow of energy in an ecosystem and understand the concept of energy loss at each trophic level.
• Create simple food chains and more complex food webs to demonstrate interdependence between organisms in different habitats.
• Recognise the importance of biodiversity and balanced ecosystems for sustainability.

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Key Vocabulary

• Producer
• Consumer (Primary, Secondary, Tertiary)
• Decomposer
• Food chain
• Food web
• Energy transfer
• Habitat
• Interdependence
• Ecosystem

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Resources

• Projector/whiteboard
• Images or printed cards of various plants and animals (e.g. grass, rabbit, fox, fungi)
• A3 paper and coloured pens for groups
• "Food Chain Web" worksheet (scaffolded with blank food chain templates)
• Energy pyramid diagram (printed or projected)
• Sticky notes for student responses

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Lesson Structure

Starter (10 minutes):

Engage with the concept of producers and consumers

• Begin with a quick pair-share discussion: “What is something you ate yesterday? Where do you think this food originally came from in nature?”
• Show colourful images of a simple food chain (grass → rabbit → fox) and ask students to identify which are producers and which are consumers.
• Introduce the definitions of producers and consumers formally on the board.

National Curriculum alignment: Engage students in using scientific vocabulary confidently (Working scientifically).

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Main Activity (35 minutes):

Activity 1: Food Chain Building (15 minutes)

• Split class into groups of 5. Each group receives a set of organism cards (plants, herbivores, carnivores, decomposers).
• Task: Arrange the cards to create a food chain and label roles (producer, consumer 1°, 2°, etc.).
• Introduce the concept of energy flow: explain with an energy pyramid that energy decreases along the chain.
• Groups briefly present their chains and explain energy flow.

Activity 2: Food Web Creation & Interdependence (20 minutes)

• Using the same groups, challenge students to expand their chains into a food web on A3 paper, linking multiple food chains together.
• Encourage them to think of different possible food interactions and include decomposers.
• Prompt students to highlight points of interdependence and discuss what might happen if one species was removed (impact on ecosystem balance).
• Circulate to support and challenge with questions such as:
  • “Which species are most important for energy flow?”
  • “How does the removal of a consumer affect the producers?”
• Groups stick their food webs on the wall for gallery viewing.

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Plenary (10 minutes):

Exit Ticket & Reflection

• Each student writes on a sticky note:
  1. One new thing they learned about food chains or webs.
  2. One question they still have about ecosystems.
• Select and discuss 3–4 student responses to consolidate learning.
• Summarise key points: energy flow, interdependence, importance of biodiversity.
• Introduce next lesson’s theme: Adaptations of organisms to their environment.

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Assessment

• Formative assessment through group presentations and peer discussion during activities.
• Use stickies from plenary as informal assessment to gauge understanding and identify misconceptions.
• Teacher observation of students’ ability to apply vocabulary and construct food chains/webs.
• Mark and provide feedback on "Food Chain Web" worksheet and group work.

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Differentiation

• Support: Provide pre-cut, labelled organism cards with pictures for EAL or SEN students.
• Challenge: More able students can add predators or omnivores, and calculate energy loss percentages in the food chain.
• Visual aids and scaffolded worksheet to support different learning styles.

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Safety and Behaviour Management

• Ensure calm group work and sharing of resources.
• Emphasise respect for peers’ ideas during presentations and gallery walk.

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Cross-Curricular Links

• English: Use of precise scientific vocabulary and oral communication skills during group presentations.
• Geography: Link ecosystems to real-world locations students have studied.

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Teacher Notes:

• Encourage enthusiasm by relating food chains to students’ everyday lives (e.g., pets, local parks).
• Use questioning to deepen understanding, e.g., “What would happen if all the grass died? How would that affect us?”
• Consider using digital tools (e.g. interactive food chain builders) if available for homework extension.

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This lesson ensures that students meet the key stage 3 National Curriculum requirements for understanding energy flow and interdependence in ecosystems in an accessible and engaging way. The practical food chain and food web construction activities will enhance scientific thinking and literacy skills.