Science · Class 10
Our Environment
Ecosystem, food web, ozone layer, and waste management.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Ecosystems involve biotic and abiotic components linked by energy flow and nutrient cycling. Food chains, webs, trophic levels, 10% energy law, ozone layer, waste management, and biomagnification are key topics.
Ecosystem
- Producers → primary consumers → secondary → tertiary
- Decomposers recycle nutrients
- 10% law: only ~10% energy passes to next trophic level
Ozone & Environment
- O₃ in stratosphere blocks UV radiation
- CFCs deplete ozone layer
- Biomagnification: DDT concentration increases up food chain
- 3 R's: Reduce, Reuse, Recycle
Waste Management
- Biodegradable vs non-biodegradable
- Composting, vermicomposting
- Landfills and pollution control
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Food chain energy
Grass has 10000 J. Energy at deer level (herbivore)?
- 1~10% transferred per level
- 2Deer gets ≈ 1000 J
- 3Next carnivore ≈ 100 J
Answer
≈ 1000 J at primary consumer
Ozone depletion
Why are CFCs harmful?
- 1CFCs release Cl radicals in stratosphere
- 2Catalyse ozone breakdown
- 3More UV reaches Earth — skin cancer risk
Answer
They destroy stratospheric ozone
Key Points to Remember
- ✓ Abiotic: soil, water, air, sunlight
- ✓ Biotic: plants, animals, microbes
- ✓ Garbage segregation protects environment
Exam Tips
- • Draw food web with arrows for energy flow
- • Explain biomagnification with DDT example
- • Know ozone formation/destruction basics
Practice MCQs — Our Environment
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
10% energy law applies to: