🧬 Class 10 Science – How do Organisms Reproduce? Interactive Visual Revision Notes
Aligned with the Class 10 Science syllabus. Independently created study material. Not affiliated with or endorsed by NCERT.
Real-World Connection: Every mango on a tree, every kitten in a litter, and every human baby is the result of reproduction — living things making copies of themselves. Some organisms like amoeba simply split in half, while others go through the complex process of fertilisation. Without reproduction, every species would disappear within one generation, so it is truly the most important life process of all!
🌱 Topic 1: Why Do We Reproduce?
Living things make more of themselves.
Life does not last forever.
Babies carry life forward.
Without babies, species would end.
Reproduction keeps life going on Earth.
🧬 Topic 2: DNA Copying
Cells have DNA inside them.
DNA is like a recipe book.
It tells body how to grow.
DNA copies itself before new baby.
Small changes happen during copying.
🌿 Topic 3: Why Variation Matters
No two copies are exactly same.
Small changes are called variations.
Variations help in changing weather.
Some babies survive better than others.
Variations keep the species safe.
🔬 Topic 4: Fission and Fragmentation
Amoeba splits into two halves.
This splitting is called fission.
Spirogyra breaks into small pieces.
Each piece grows into new plant.
Simple organisms use these methods.
🌸 Topic 5: Budding and Spore Formation
Hydra grows a small bud.
The bud breaks off and grows.
Bread mould makes tiny spores.
Spores fly in the air.
Each spore can become new plant.
🌱 Topic 6: Vegetative Propagation
New plants grow from old parts.
Potato eyes grow new plants.
Rose cuttings make new rose plants.
Roots, stems, leaves can grow babies.
No seeds are needed for this.
🌼 Topic 7: Flower Parts
Flowers help plants make seeds.
Stamen is the male part.
Pistil is the female part.
Petals attract bees and butterflies.
Sepals protect the young bud.
🌻 Topic 8: Pollination and Fertilisation
Pollen moves from stamen to pistil.
Wind or bees carry the pollen.
Pollen joins with the egg cell.
This joining is called fertilisation.
A seed starts to form now.
🧑 Topic 9: Human Reproductive System
Boys have testes inside their body.
Girls have ovaries inside their body.
Testes make tiny cells called sperm.
Ovaries make cells called eggs.
Baby grows inside the mother's womb.
💚 Topic 10: Menstruation and Contraception
Every month the uterus gets ready.
If no baby, the lining sheds.
This monthly bleeding is called periods.
Contraception stops a baby from forming.
Condoms and pills are common methods.
🎨 Section 2 — Easy Illustrations
Hover over elements to explore. Diagrams animate as you scroll.
Fig 1: Binary fission – Amoeba splits into two new cells.
Fig 2: A flower with all its parts labelled.
Fig 3: Hydra reproduces by budding – a bud grows and breaks off.
Fig 4: A bee carries pollen from one flower to another.
Fig 5: Male and female reproductive systems – simple overview.
✏️ Section 3 — Worked Examples
🔶 Example 1: Why does bread get mouldy?
Old bread gets a fuzzy green layer. Why?
1Bread mould makes tiny spores.
2Spores land on bread from air.
3They grow into new mould.
4Warmth and moisture help them grow.
✔ Answer: Mould spreads by tiny spores in air.
🔶 Example 2: Why do flowers have bright colours?
Many flowers are red, yellow, or purple. Why?
1Flowers need pollen to make seeds.
2Bees visit bright flowers.
3Bees carry pollen to other flowers.
4This is called pollination.
✔ Answer: Bright colours attract bees for pollination.
🔶 Example 3: Why do potato eyes sprout?
Old potatoes grow small green shoots. Why?
1Potato eyes are small buds.
2Buds can grow into new plants.
3This is vegetative propagation.
4No seeds are needed here.
✔ Answer: Potato eyes are buds that grow new plants.
📋 Section 4 — Cheat Sheet
Word
Meaning
Reproduction
Making new living things
DNA
Recipe book inside each cell
Variation
Small differences between babies
Fission
One cell splits into two
Budding
A bud grows and breaks off
Spore
Tiny seed-like cell in air
Pollination
Pollen moves to the pistil
Fertilisation
Sperm joins with egg
Stamen
Male part of a flower
Pistil
Female part of a flower
Uterus
Where baby grows in mother
Contraception
Ways to prevent pregnancy
🏠 Section 5 — Take-Home Handout
Part A — Fill in the Blanks
1. Making new living things is called __________.
2. DNA is like a __________ book inside cells.
3. Amoeba splits into two by __________.
4. The male part of a flower is the __________.
5. A baby grows inside the mother's __________.
Part B — True or False
1. Hydra reproduces by binary fission. ( )
2. Pollen is carried by wind or bees. ( )
3. All babies are exactly like their parents. ( )
4. Spores help bread mould to spread. ( )
5. Ovaries make sperm cells. ( )
Part C — Answer These
1. What is the difference between fission and budding?
2. Why are variations important for a species?
3. Name two methods of contraception.
Part D — Match the Columns
Column A
Column B
1. Amoeba
a. Budding
2. Hydra
b. Spore formation
3. Bread mould
c. Vegetative propagation
4. Potato
d. Binary fission
5. Rose
e. Cutting
Part E — Draw and Label
Draw a flower and label these parts: petal, sepal, stamen, pistil, ovary.
1. Making new living things is called reproduction.
2. DNA is like a recipe book inside cells.
3. Amoeba splits into two by binary fission.
4. The male part of a flower is the stamen.
5. A baby grows inside the mother's uterus.
Part B: True or False
1. Hydra reproduces by binary fission. → False — Hydra reproduces by budding; binary fission is used by organisms like amoeba and bacteria.
2. Pollen is carried by wind or bees. → True — Pollination is the transfer of pollen from anther to stigma; wind (anemophily) and bees/insects (entomophily) are common agents.
3. All babies are exactly like their parents. → False — Sexual reproduction introduces variations; offspring resemble parents but are not identical (except identical twins).
4. Spores help bread mould to spread. → True — Bread mould (Rhizopus) produces spores in sporangia; when spores are released, they spread and germinate on new food.
5. Ovaries make sperm cells. → False — Ovaries produce egg cells (ova); sperm cells are produced by testes.
Part C: Answer These
1. Difference between fission and budding:
F
Fission (e.g. Amoeba): the parent organism splits into two equal daughter cells; the parent effectively disappears and two new organisms form.
B
Budding (e.g. Hydra): a small outgrowth (bud) forms on the parent, grows into a new organism, and then separates. The parent continues to exist.
2. Why are variations important for a species?
1
Variations mean individuals in a species are not all identical.
2
When the environment changes (disease, climate), some individuals with useful variations survive while others may not.
3
Over many generations, this leads to evolution and adaptation; without variation, a single disease could wipe out an entire species.
3. Name two methods of contraception:
1
Barrier method — condoms (male/female) physically block sperm from reaching the egg; also protect against STIs.
2
Oral contraceptive pills — hormonal pills taken by females that prevent ovulation (the release of an egg).
Part D: Match the Columns
1. Amoeba → d. Binary fission (splits into two equal halves)
2. Hydra → a. Budding (small bud grows and detaches)
3. Bread mould → b. Spore formation (sporangia release thousands of spores)
4. Potato → c. Vegetative propagation (buds/eyes on potato grow into new plants)
5. Rose → e. Cutting (a stem cutting placed in soil grows roots and develops into a new plant)
Part E: Draw and Label — A Flower
Your diagram should show a simple flower cross-section with these labels:
Petal — coloured leaf-like structure that attracts pollinators
Sepal — green leaf-like structure at the base; protects the bud
Stamen — male part; consists of anther (makes pollen) + filament (stalk)