Food Web Puzzles & Energy Flow

• how energy flows through food chains and food webs, and why it only ever moves in one direction.
• the 10% law of energy transfer, ecological pyramids, and why food chains rarely exceed 4-5 trophic levels.
• olympiad-style puzzles: biomagnification, keystone species removal, and inverted pyramids.

1. Trophic levels — producers, primary/secondary/tertiary consumers, and decomposers, and how energy decreases at each step.
2. The 10% law — only about 10% of energy is passed to the next trophic level; the rest is lost as heat through respiration.
3. Ecological pyramids — pyramids of energy (always upright), numbers, and biomass (sometimes inverted, e.g., in ponds or on a single large tree).
4. Biomagnification and keystone species — how non-biodegradable toxins concentrate up a food chain, and why removing one keystone species can collapse a whole web.

A grassland food chain: Grass -> Grasshopper -> Frog -> Snake -> Hawk. If grass fixes 100,000 kJ of energy, calculate the energy available to the snake (3rd consumer level).

Step 1 — Grass (producer): 100,000 kJ
Step 2 — Grasshopper (10% of 100,000): 10,000 kJ
Step 3 — Frog (10% of 10,000): 1,000 kJ
Step 4 — Snake (10% of 1,000): 100 kJ

• Thinking energy cycles back to producers — energy flow is one-way; only matter/nutrients are recycled.
• Assuming all ecological pyramids are always upright — biomass and number pyramids can be inverted.
• Confusing a food chain (single path) with a food web (many interconnected paths).

• Calculate the energy available at the 4th trophic level if a producer fixes 50,000 kJ.
• Explain why the pyramid of energy is always upright but the pyramid of biomass is not always.
• Give one real example of biomagnification and identify which organism is most affected.

Open the Practice tab for graded questions on Food Web Puzzles & Energy Flow.

• Use the platform-native live simulation or PhET-style tool for this topic (number line, Venn, physics playground, molecule builder, sensor dashboard, etc.).
• Mirror / body / home activity: physically do the concept (count objects, measure, role-play) and photograph or describe for portfolio.
• Voice or text reflection with AI Mentor: explain the concept to a younger student or family member.

• "Explain this concept to a Class 6 student using one real example from an Indian home, school, market, or festival."
• "What is one common mistake students make here, and how would you catch yourself making it?"
• Stretch: "How does this connect to coding, robotics, money, health, environment, or a future career?"

• Complete the core practice + one extension activity (photo, table, short reflection, or mini-project) for base XP + topic badge.
• 5-7 day streak or family discussion note = multiplier + visible artifact in parent/principal dashboard.
• Best real-world application stories (anonymised) featured on class or national leaderboard.

• One hands-on project or measurement using the Drishti kit or household items that makes the concept physical.
• Direct link to at least one Future Skill track (Money Management, Green Tech, Cyber Defenders, Micro-Entrepreneurship, AI Mastery, Sustainable Living, Personality Development).
• Coding extension where relevant (simple script, simulation, or data logging).

This material emphasises experiential "learning by doing", competency (apply/create/analyse), vocational exposure, critical thinking, and multidisciplinary connections. Designed to feed live worlds, AI Mentor (with memory), gamification, robotics, parent analytics, and future skills — not just exam prep.

Portfolio Evidence Idea: Your photo/table/reflection/project + one sentence on "How this helps me in real life or a possible future path."

Open the Practice tab for aligned questions (easy/medium/hard + case-based) with full AI scaffolding.

See curriculum for cross-links and the full future-skills/robotics chapters.