🌿 Class 10 Science — Our Environment Original Visual Revision Notes
Aligned with the Class 10 Science syllabus. Independently created study material. Not affiliated with or endorsed by NCERT.
Real-world connection: Think of our environment like a giant web of connections. When a spider catches a fly, it is the predator; the fly was a consumer of plants; the plant grew using sunlight. Pull one thread out of this web — say, remove all the frogs — and the whole web shakes: insects multiply, crops suffer, and the animals that ate frogs starve. This lesson explains how energy and matter flow through that web, and why every species (even tiny decomposers) matters.
🌿 Topic 1: What Is an Ecosystem?
An ecosystem is a place where life exists.
It has living and non-living parts together.
A pond is one ecosystem example.
A forest is also an ecosystem.
All parts depend on each other to live.
🌍 Topic 2: Biotic and Abiotic Parts
Biotic means all living things around us.
Plants and animals are biotic parts.
Abiotic means non-living things around us.
Sun, water, and air are abiotic parts.
Both parts work together in nature.
🌱 Topic 3: Producers, Consumers, Decomposers
Producers are plants that make their food.
They use sunlight to make food.
Consumers are animals that eat other things.
Decomposers break down dead things into soil.
Fungi and bacteria are decomposers.
🔗 Topic 4: Food Chains
A food chain shows who eats whom.
It starts with a plant always.
A small animal eats the plant next.
A big animal eats the small animal.
Energy moves in one direction only.
🕸 Topic 5: Food Webs
A food web is many food chains joined.
Animals can eat many different things.
Food webs show all eating links together.
They are more real than food chains.
If one animal dies, others get affected.
📊 Topic 6: Trophic Levels and Energy Flow
Each step in a food chain is a level.
Plants are at the first level always.
Only 10% energy passes to the next level.
This is called the 10% law.
Top animals get the least energy.
☠ Topic 7: Biological Magnification
Chemicals enter the food chain through water.
Small animals take in little poison.
Big animals eat many small ones, so more poison.
Poison increases at each higher level.
Humans at the top get the most poison.
🛡 Topic 8: Ozone Layer
Ozone is a special layer high in the sky.
It blocks harmful rays from the sun.
These harmful rays are called UV rays.
Ozone is made of three oxygen atoms.
It keeps us safe from skin problems.
⚠ Topic 9: Ozone Depletion
CFCs are gases that destroy the ozone layer.
CFCs come from old fridges and sprays.
They make a hole in the ozone layer.
More UV rays reach Earth because of this.
We must stop using things with CFCs.
♻ Topic 10: Managing Garbage
Biodegradable waste breaks down in nature.
Food scraps and paper are biodegradable.
Non-biodegradable waste does not break down.
Plastic and glass are non-biodegradable.
We must reduce, reuse, recycle our waste.
🎨 Section 2 — Easy Illustrations
Diagram 1: Biotic and abiotic parts of an ecosystem
Diagram 2: A simple food chain with four levels
Diagram 3: Energy flow and the 10% law at each level
Diagram 4: How poison builds up in the food chain
Diagram 5: How the ozone layer protects Earth
✏️ Section 3 — Worked Examples
📝 Example 1: Build a Food Chain
Make a food chain from: eagle, grass, snake, frog.
1
Find the producer. Grass is the plant.
2
Who eats grass? The frog eats grass.
3
Who eats the frog? The snake does.
4
Who eats the snake? The eagle does.
Answer: Grass → Frog → Snake → Eagle
📝 Example 2: Use the 10% Law
Plants have 10000 J energy. How much do herbivores get?
Direction of arrows shows direction of energy flow. Grass absorbs solar energy; only 10% passes to the deer; only 10% of that (1% of the original) reaches the tiger.