Science (EVS K-5) · Class 7

Active learning ideas

Interdependence: Food Chains and Food Webs

Explore the amazing connections in nature by investigating who eats whom in a forest. We will become ecological detectives, tracing the flow of energy from a tiny blade of grass all the way to a mighty tiger.

• CBSE Learning Outcomes
• NCERT Class 7 Science: Chapter 17 - Forests: Our Lifeline

• 20–45 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Simulation Game
• 30 min · Whole Class

Food Web String Game

Assign each student a role (sun, plant, deer, tiger, vulture) with a picture card. Students pass a ball of string from the organism that is eaten to the organism that eats it, creating a physical web that demonstrates interdependence.

Explain the role of producers, consumers, and decomposers in a forest.

Facilitation Tip

After the web is formed, gently tug on one string (e.g., 'remove the deer') to show how it affects many others.

What to look for

Exit Ticket: Ask students to draw a four-step food chain involving a specific Indian animal, like a peacock, and label the producer, primary consumer, and secondary consumer.

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

Activity 02

• Simulation Game
• 45 min · Small Groups

Build a Local Food Chain

In small groups, students use chart paper and pictures (from magazines or drawn) to create a food chain using organisms found in their local area or a specific Indian habitat like the Sunderbans or the Thar Desert.

Analyse the effect of removing one organism from a simple food web.

Facilitation Tip

Provide a list of local flora and fauna to guide students who may be struggling for ideas.

What to look for

Project: Students research and create a poster or a digital presentation of the food web of a specific Indian National Park (e.g., Ranthambore, Kaziranga) and explain the consequences of a specific animal becoming endangered.

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

Activity 03

• Simulation Game
• 20 min · Pairs

Decomposer Discovery Jar

Students create a mini-compost jar with soil, vegetable scraps, leaves, and a little water. Over a few weeks, they observe the process of decomposition and understand the role of unseen decomposers like bacteria and fungi.

Justify the construction of a simple food chain found in a local forest environment.

Facilitation Tip

Ensure jars have small air holes and are kept in a warm, but not directly sunny, spot to speed up decomposition.

What to look for

Students use a checklist to rate their confidence in defining key vocabulary terms and explaining the difference between a food chain and a food web.

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

A few notes on teaching this unit

Start with the simple, linear concept of a food chain using familiar examples. Use visual aids like flashcards or drawings to build the chain step-by-step. Then, introduce complexity by showing how one animal can be part of multiple chains, leading to the idea of a web. Hands-on activities like the string game are excellent for making this abstract concept tangible.

By the end of these activities, your students will be able to design a food chain, explain how it fits into a larger food web, and predict what happens when one link in the chain is broken.

---

Watch Out for These Misconceptions

• Plants create their own energy from nothing.

  Plants are producers, but they do not create energy. They convert light energy from the sun into chemical energy (food) through photosynthesis.

• The animal at the top of the food chain is the most important.

  Every organism in a food web is important for its stability. The removal of producers, like plants, would cause the entire food web to collapse, showing their foundational importance.

• Food chains are always simple, straight lines.

  Food chains show one path of energy flow. In reality, most animals eat more than one type of food, so multiple food chains connect to form a more complex and realistic food web.

• Decomposers like fungi and bacteria are just germs and are bad for the environment.

  Decomposers are essential recyclers. They break down dead organic matter and return vital nutrients to the soil, which plants then use to grow.

---

Methods used in this brief

• Simulation Game