Schooling · Class 10 · Science · Our Environment · Chapter on a page
CBSE Class 10 · Science · NCERT Science
Our Environment: chapter on a page
A cut of Shishya's notes for this chapter: the first paragraph of the introduction and the key ideas, formulas and facts, common mistakes and quick revision lists, word for word. Nothing is added or reworded; the worked examples are left out (they are on the chapter page).
About the notes: Written by Shishya's AI on 26 Sept 2026 from the chapter's title and class level, in Shishya's own words — not a copy or summary of the textbook. Read the official chapter for the book's own text, activities and exercises.
This note's current text has no applied fact-check on record.
Mind map
Drawn from the same notes by a fixed rule (no AI): each label is the item's own words — its bold term, its label before a colon, a short formula as written, or its first words.
The mind map as a list
- Key ideas
- An ecosystem includes all living…
- Producers are green plants and…
- A food chain shows a single pathway…
- Only about 10 per cent of energy…
- Biological magnification occurs when…
- Biodegradable substances (vegetable…
- The ozone layer in the stratosphere…
- Formulas and facts
- 10 per cent law
- Trophic levels
- Ozone formation
- Ozone depletion
- Biodegradable waste
- Non-biodegradable waste
- Biological magnification
- Watch out for
- Thinking energy increases or stays…
- Confusing food chain with food web
- Believing all waste eventually…
- Assuming biological magnification…
- Thinking ozone in the upper…
What this chapter is about
This chapter explores how living organisms interact with each other and with their physical surroundings. A Class 10 student learns about ecosystems, the flow of energy through food chains and food webs, and how matter cycles through nature. Understanding these connections helps explain why balance in nature matters.
Key ideas
- An ecosystem includes all living organisms (biotic components) and non-living factors like air, water, soil, sunlight and temperature (abiotic components) in a given area, functioning together as a unit.
- Producers are green plants and certain bacteria that make their own food through photosynthesis; consumers are organisms that depend on others for food; decomposers like bacteria and fungi break down dead matter and release nutrients back into soil.
- A food chain shows a single pathway of energy transfer: producer → primary consumer → secondary consumer → tertiary consumer. Energy decreases at each step.
- Only about 10 per cent of energy available at one trophic level passes to the next level; the rest is lost as heat during life processes.
- Biological magnification occurs when non-biodegradable chemicals like pesticides become more concentrated at higher trophic levels of a food chain.
- Biodegradable substances (vegetable peels, paper, cotton) can be broken down by microorganisms; non-biodegradable substances (plastic, glass, certain pesticides) cannot be decomposed naturally and persist in the environment.
- The ozone layer in the stratosphere absorbs harmful ultraviolet radiation from the sun; chlorofluorocarbons (CFCs) from refrigerators and aerosols destroy ozone molecules.
- Proper waste management—reducing, reusing and recycling—helps protect ecosystems from pollution.
Formulas and facts to remember
- 10 per cent law: Only about 10% of energy is transferred from one trophic level to the next; the rest is used in metabolism or lost as heat.
- Trophic levels: Producer (first) → Primary consumer (second) → Secondary consumer (third) → Tertiary consumer (fourth).
- Ozone formation: O₂ → O + O (UV splits oxygen); O + O₂ → O₃ (ozone forms).
- Ozone depletion: CFCs release chlorine atoms in the stratosphere; each chlorine atom can destroy thousands of ozone molecules.
- Biodegradable waste: Broken down by bacteria and fungi within weeks or months.
- Non-biodegradable waste: Persists in the environment for decades or centuries; examples include polythene bags, aluminium cans, DDT.
- Biological magnification: Concentration of pesticides increases as we move up the food chain—highest in top predators.
Common mistakes
- Thinking energy increases or stays constant as it moves up a food chain → Energy decreases; only 10% transfers to each higher level.
- Confusing food chain with food web → A food chain is a single linear pathway; a food web is an interconnected network of many food chains.
- Believing all waste eventually decomposes → Non-biodegradable materials like plastic do not break down naturally and accumulate.
- Assuming biological magnification affects all substances equally → Only non-biodegradable, fat-soluble chemicals like DDT magnify up the food chain.
- Thinking ozone in the upper atmosphere is harmful → Stratospheric ozone protects us; ground-level ozone is the pollutant.
Quick revision
- Ecosystem = biotic (living) + abiotic (non-living) components interacting together.
- Energy flow: Sun → Producers → Consumers → Decomposers; only 10% passes to each next level.
- Shorter food chains mean more energy available to top consumers.
- Biological magnification: pesticide concentration rises at higher trophic levels.
- Biodegradable waste decomposes; non-biodegradable waste persists—reduce, reuse, recycle.
- CFCs destroy ozone; ozone loss increases UV radiation reaching Earth, causing health and ecological harm.