🌈 Chapter Title in Colourful Style
How Nature Works in Harmony
Class 8 Science – Curiosity (NCERT)
🎯 What This Chapter Teaches You
This beautiful chapter shows how everything in nature is connected like a giant colourful web! 🌍🦒🌳
From elephants walking safely under railway bridges to tiny mushrooms recycling waste, nature keeps perfect balance.
You will learn:
- 🏡 What a habitat is and its living (biotic) & non-living (abiotic) parts
- 👥 How populations → communities → ecosystems are built
- 🍃🌞 How plants, animals, sunlight, water, soil all depend on each other
- 🥗 Who eats whom – food chains & food webs
- ♻️ How nothing is wasted in nature (decomposers rock!)
- ⚖️ How one small change can cause big effects
- 🤝 Different relationships: mutualism, competition, parasitism
- 🌱 Why we must protect ecosystems and farm sustainably
Big Idea: Nature is a perfectly balanced, colourful orchestra – every player matters!
2️⃣ Complete Concept-Wise Explanation (Super Colourful & Easy to Remember!)
🌳 Opening Scene – Why Elephants Visit Villages 🐘
Real story: In states like Odisha, Jharkhand, West Bengal, Assam, Chhattisgarh → elephants enter farms.
Reason?
- 🌧️ Less rainfall + 🌲 cutting forests → plants dry up, waterholes disappear.
- 🐘 Elephants search for food (bananas, sugarcane) → damage crops, sometimes harm people.
Solution: Elephant Corridors – safe green paths connecting forests so elephants travel without meeting humans.
Lesson: One change (deforestation) affects many lives – everything in nature is linked!
🏞️ 12.1 How Do We Experience Our Surroundings?
Habitat = Home of an organism (big forest or tiny tree bark).
Activity 12.1 🌼 Let us explore
Go see two habitats (pond, forest, farm, big tree). List:
Living (Biotic): plants, animals, fish, birds
Non-living (Abiotic): water, soil, sunlight, air, temperature
Key Terms:
- 🟢 Biotic components = All living things
- 🟤 Abiotic components = All non-living things
Example: Fish get food (small plants/animals) and oxygen from water. Pond also has frogs, snakes, dragonflies, lotus, algae.
Harmony tip: Night snake & day rodent share same habitat but use different times → peaceful living!
👨👩👧👦 12.2 Who All Live Together in Nature?
Population = Many individuals of SAME kind in one place (all fish of one type in pond).
Activity 12.2 📊 Let us record
Count organisms in 1m×1m area → see different populations.
If only one population? → Too much competition → many die.
Community = All different populations together (all plants + animals + microbes in a habitat).
Ever heard of… Pollination 🐝
Flowers → pollen transferred by insects/birds/wind → fruits & seeds formed. Beautiful mutual help!
❓ 12.3 Does Every Organism Matter?
YES! Removing one affects others.
Activity 12.3 🔬 Pond study
- Pond A (with fish) → fewer dragonflies → more bees/butterflies → more pollination → more flowering plants.
- Pond B (no fish) → more dragonflies → fewer pollinators → fewer plants.
Indirect effect: Fish help plants grow better without directly touching them!
🔗 12.4 Types of Interactions
Three types:
- Biotic ↔ Abiotic (e.g., earthworms need moist soil)
- Abiotic ↔ Abiotic (sunlight heats air)
- Biotic ↔ Biotic (frog eats insect)
All together form ECOSYSTEM!
Ecosystems: Aquatic (ponds, rivers) | Terrestrial (forests, grasslands) | Human-made (farms)
Biotic helps abiotic too: Plants give oxygen, hold soil, keep moisture.
🥗 12.5 Who Eats Whom? – Food Relationships
Activity 12.5 🦌 Classify eating habits
- Producers (plants) → make own food (photosynthesis)
- Consumers:
- Herbivores (deer) → only plants
- Carnivores (leopard) → only animals
- Omnivores (fox) → both
Activity 12.6 ➡️ Food chains
Examples:
Grass 🡒 Hare 🡒 Fox
Grass 🡒 Grasshopper 🡒 Frog 🡒 Snake 🡒 Eagle
Activity 12.7 🏔️ Energy pyramid
Most producers at bottom → fewer top carnivores.
Activity 12.8 🕸️ Food web
Many interconnected chains = food web.
♻️ 12.6 What Happens to Waste?
Decomposers (mushrooms, bacteria) break dead matter → nutrients back to soil.
Nothing wasted in nature!
Migratory birds 🐦 travel to India in winter → help pollination, pest control.
⚡ 12.7 One Change → Many Effects
Pollution kills pond plants → less oxygen → fish die → more insects → farmers use pesticides → harm environment.
Frog export story: Fewer frogs → more pests → more chemicals → banned export.
⚖️ 12.8 How Balance is Maintained
- Competition controls population
- Relationships:
Mutualism (both benefit – bee & flower)
Commensalism (one benefits, other okay – orchid on tree)
Parasitism (one benefits, other harmed – tick on dog)
🌍 12.9 Benefits & Protection
Ecosystems give air, water, food, medicine, beauty.
Sundarbans mangroves protect from storms, absorb CO₂. Threats: cutting, pollution.
Protected areas: National parks, sanctuaries save habitats.
Human-made ecosystems (farms) need sustainable care.
Green Revolution helped food but harmed soil → now move to organic farming.
3️⃣ Important Definitions (Colour-Coded for Memory!)
- Habitat: Natural home providing food, water, shelter, space.
- Biotic: All living things.
- Abiotic: All non-living things (sun, water, soil…).
- Population: Same species individuals in one area.
- Community: All populations together.
- Ecosystem: Community + abiotic environment.
- Producers: Make own food (plants).
- Consumers: Herbivores, Carnivores, Omnivores.
- Decomposers: Recycle waste (fungi, bacteria).
- Food chain/web: Who eats whom links.
- Trophic level: Position in food chain.