NCERT Solutions for Class 8th Science Chapter 12 How Nature Works in Harmony
Updated on 2026-09-19
About this chapter
A habitat is the place that gives an organism the conditions it needs. Its living parts are the biotic components ; air, water, soil, sunlight and temperature are the abiotic components . Organisms of one kind in one place at one time form a population ; the different populations sharing a habitat form a community ; the community together with the abiotic components it interacts with is an ecosystem . Green plants are producers — they alone bring energy into the ecosystem, from sunlight. Consumers pass that energy along, and decomposers break dead matter down and return the nutrients to the soil. A food chain shows who eats whom; because most organisms are eaten by more than one kind of animal, chains link up into a food web . An organism's place in a chain is its trophic level . Energy fl
- Chapter opener
- .1 How Do We Experience and Interpret Our Surroundings?
- .2 Who All Live Together in Nature?
- .3 Does Every Organism in a Community Matter?
- .5 Who Eats Whom?
- .6 What Happens to Waste in Nature?
- .9 What Are the Benefits of an Ecosystem?
- .9.2 How do healthy ecosystems serve our farms?
- End-of-chapter questions
- End-of-chapter projects
Quick revision
| Term | What it means | Example from the chapter | Where it appears |
|---|---|---|---|
| Habitat | The place that provides an organism the right conditions to live and grow | A pond, a forest, even the bark of a tree | 12.1 |
| Biotic components | The living parts of a habitat | Fish, algae, deer, mushroom, bacteria | 12.1 |
| Abiotic components | The non-living parts of a habitat | Air, sunlight, water, temperature, soil | 12.1 |
| Population | A group of organisms of the same kind in a habitat at a given time | 20 plants of one kind in a 1 m × 1 m plot | 12.2 |
| Community | The different populations that share one habitat | Plants + animals + microorganisms of a pond | 12.2 |
| Ecosystem | A community and the abiotic components it interacts with | Pond, river, lake (aquatic); forest, farm (terrestrial) | 12.4 |
| Producer / autotroph | Makes its own food by photosynthesis (auto = self, troph = food) | Grass, millet, banyan tree | 12.4 |
| Consumer / heterotroph | Cannot make its own food; depends on other organisms | Deer (herbivore), leopard (carnivore), crow (omnivore) | 12.4 |
| Decomposer / saprotroph | Breaks down dead matter into simpler substances (sapro = rotten) | Mushroom, bacteria, beetles on elephant dung | 12.6 |
| Food chain / food web | A sequence of who eats whom / interlinked food chains | Grass → Grasshopper → Frog → Snake → Eagle | 12.5 |
| Trophic level | The position an organism occupies in a food chain | Producers 1st, herbivores 2nd, small carnivores 3rd | 12.5 |
| Mutualism, commensalism, parasitism | Both benefit / one benefits and the other is unaffected / one benefits and the other is harmed | Bee and flower; orchid on a tree; tick on a dog | 12.8 |
Exercises
- Chapter opener — Probe and ponder Page 190
- .1 How Do We Experience and Interpret Our Surroundings? — Activity 12.1: Let us explore Page 19112
- .1 How Do We Experience and Interpret Our Surroundings? — In-text Questions Page 19212
- .2 Who All Live Together in Nature? — Activity 12.2: Let us record Page 19312
- .2 Who All Live Together in Nature? — In-text Questions Page 19412
- .3 Does Every Organism in a Community Matter? — Activity 12.3: Let us read Page 194–19512
- .4 What Are the Different Types of Interactions Among Organisms and their Surroundings? — Activity 12.4: Let us relate and identify Page 19612
- .4 What Are the Different Types of Interactions Among Organisms and their Surroundings? — In-text Questions Page 19712
- .4 What Are the Different Types of Interactions Among Organisms and their Surroundings? — Activity 12.5: Let us classify Page 197–19812
- .5 Who Eats Whom? — In-text Questions Page 19812
- .5 Who Eats Whom? — Activity 12.6: Let us link (relate) Page 19912
- .5 Who Eats Whom? — Activity 12.7: Let us draw Page 19912
- .5 Who Eats Whom? — Activity 12.8: Let us trace and link Page 20012
- .6 What Happens to Waste in Nature? — In-text Questions Page 20112
- .6 What Happens to Waste in Nature? — Ever heard of … Page 20112
- .7 How Does One Change Lead to Another? / 12.8 How Do Interactions Maintain Balance in Ecosystems? — In-text Questions Page 20212
- .9 What Are the Benefits of an Ecosystem? — In-text Questions Page 20412
- .9.1 Human-made ecosystems / 12.9.2 How do healthy ecosystems serve our farms? — In-text Questions Page 20512
- .9.2 How do healthy ecosystems serve our farms? — Activity 12.10: Let us survey Page 20512
- .9.2 How do healthy ecosystems serve our farms? — In-text Questions Page 20612
- End-of-chapter questions — Keep the curiosity alive Page 207–208
- End-of-chapter projects — Discover, design, and debate Page 208–209