Page 1: Introduction

Environment: everything around us (living + non-living).

Ecosystem: interaction between biotic and abiotic components.

Chapter covers ecosystem structure, energy flow, environmental problems.

Page 2: Ecosystem Components

• Biotic: producers, consumers (primary, secondary, tertiary), decomposers
• Abiotic: sunlight, water, temperature, soil

Page 3: Food Chain

Linear transfer of energy: producer → primary consumer → secondary → tertiary.

Example: grass → deer → lion

Page 4: Food Web

Interconnected food chains.

More stable than single chain.

Page 5: Trophic Levels

Level 1: producers (100% energy)

Level 2: herbivores

Level 3: carnivores

Level 4: top carnivores

Page 6: Flow of Energy - 10% Law

Only 10% energy transferred to next level.

Lindeman’s 10% law.

Reason: energy lost as heat, digestion, movement.

Page 7: Why Few Trophic Levels

Energy decreases → insufficient at higher levels.

Maximum 4-5 levels.

Page 8: Environmental Problems

Ozone layer depletion: CFCs → UV rays → skin cancer.

Biomagnification: non-biodegradable accumulate up food chain (DDT).

Page 9: Waste Management

Biodegradable: decompose naturally (paper, food).

Non-biodegradable: do not (plastic, chemicals).

Manage: reduce, reuse, recycle.

Page 10: Key Points Summary

• Ecosystem components
• Food chain vs web
• 10% law
• Ozone depletion
• Waste types

Page 11: Practice Questions - Easy (1-10)

1. Producer example.
2. Decomposer role.
3. 10% law meaning.
4. Ozone depleting substance.
5. Biodegradable example.
6. Trophic level 1.
7. Food web advantage.
8. Biomagnification meaning.
9. Ecosystem definition.
10. Top carnivore position.

Page 12: Practice Questions - Medium (11-20)

11. Explain 10% law with example.
12. Difference food chain and web.
13. Ozone layer importance.
14. Effect of DDT in food chain.
15. Components of ecosystem.
16. Why only 10% energy transfer.
17. Manage non-biodegradable waste.
18. Flow of energy unidirectional.
19. Trophic levels example.
20. Human position in food chain.

Page 13: Practice Questions - Hard (21-30)

21. Explain ecosystem structure with diagram description.
22. 10% law impact on trophic levels.
23. Ozone depletion causes and effects.
24. Board level biomagnification explanation.
25. Waste management importance.
26. Energy pyramid.
27. Human interference in ecosystem.
28. Food web stability.
29. Environmental protection measures.
30. Balance in ecosystem.

Page 14: Ecosystem Diagram Description

Food chain, web, trophic levels.

Page 15: Common Mistakes

• Confusing producer consumer
• More than 10% transfer
• Wrong ozone cause
• Biodegradable plastic
• Forgetting decomposers

Page 16: Previous Year Questions

10% law, ozone, food chain, waste.

Page 17: Exam Tips

• Draw food chain/web
• Explain 10% law
• List causes/effects
• Give examples
• Write full forms (CFC)

Page 18: Quick Revision Sheet

All concepts, laws.

Page 19: Final Motivation

Chapter 15 complete! Our Environment is easy and important.

Master 10% law and ozone.

**CLASS 10 SCIENCE FULLY COMPLETED!!!**

Every chapter from Chemical Reactions to Our Environment — DONE 🦖🎉

Page 20: Extra Diagrams

Food chain, web, energy pyramid.

Page 21: 10% Law

Detailed explanation.

Page 22: Ozone Depletion

Causes, effects, prevention.

Page 23: Waste Management

3R principle.

Page 24: Board Pattern

Common questions.

Page 25: Extra Practice

More questions.

Page 26: Ecosystem Balance

Importance.