🎯Here are exam-focused notes + topic-wise previous year questions (PYQs) & NCERT exercise solution -
1. Why Do Organisms Reproduce?
- Reproduction → biological process by which organisms produce new individuals of the same species.
- Ensures continuity of life & genetic variation.
2. Types of Reproduction
Asexual Reproduction
- Single parent, no gamete formation, offspring are genetically identical (clones).
- Modes of asexual reproduction:
|
Mode |
Example |
|
Fission (binary & multiple) |
Amoeba, Plasmodium |
|
Budding |
Hydra, Yeast |
|
Spore formation |
Rhizopus |
|
Regeneration |
Planaria |
|
Fragmentation |
Spirogyra |
|
Vegetative propagation |
Potato (tuber), Bryophyllum (leaf) |
Sexual Reproduction
- Involves male & female gametes → zygote → embryo.
- Leads to genetic variation → evolution.
3. Sexual Reproduction in Flowering Plants
Flower is the reproductive organ.
- Parts of a flower:
🌸 Stamen → male part → anther & filament → produces pollen (male gamete).
🌸 Carpel/Pistil → female part → stigma, style, ovary → ovules (female gamete).
Steps:
- Pollination → transfer of pollen to stigma.
- Fertilization → fusion of male & female gametes.
- Seed & fruit formation.
4. Sexual Reproduction in Humans
Human Reproductive System:
Male:
- Testes → produce sperm & hormone testosterone.
- Vas deferens → carries sperm.
- Penis → delivers sperm.
Female:
- Ovaries → produce eggs & hormone estrogen.
- Fallopian tube → site of fertilization.
- Uterus → embryo develops here.
- Vagina → birth canal.
Fertilization & Development:
- Sperm + Egg → Zygote → Embryo → Fetus.
Methods of Contraception:
- Barrier methods (condoms)
- Oral pills
- IUCD (copper-T)
- Surgical methods
5. Importance of Variation
- Variations help in survival & evolution, especially in changing environments.
🎯 Topic-Wise Previous Year Questions
Very Short Answer (1–2 Marks)
- Name the method of reproduction in Amoeba.
- What is the role of testes in humans?
- What is fertilization? Where does it occur in humans?
- Name one contraceptive method and how it works.
- Name the part of a flower that produces pollen.
Short Answer (3 Marks)
- Explain vegetative propagation with two examples.
- Write three differences between asexual and sexual reproduction.
- What is the importance of variation?
- Why are testes located outside the abdominal cavity in humans?
- Draw a labeled diagram of the human sperm or ovum.
Long Answer (5 Marks)
- Describe the human male & female reproductive systems with diagrams.
- Explain the process of fertilization & development of embryo in humans.
- Write the differences between pollination & fertilization.
- Explain the modes of asexual reproduction with examples & diagrams.
- Describe the role of hormones in human reproduction.
🌟 Tips for Exam:
Revise & practice diagrams:
- Flower (male & female parts)
- Human reproductive systems
- Sperm & Ovum
Learn key differences:
- Asexual vs Sexual reproduction
- Pollination vs Fertilization
Remember examples for each mode of reproduction.