CBSE Class 10 Science: How Do Organisms Reproduce — Notes 2026

Importance of Reproduction

• Reproduction: process by which living organisms produce offspring; ensures continuity of species
• No immediate survival need: organisms survive without reproducing; but species goes extinct if no reproduction
• DNA copying: reproduction passes genetic information to offspring; with variation enabling evolution

Asexual Reproduction Methods

• Fission: binary (Amoeba, bacteria) or multiple (Plasmodium); parent divides into 2 or many daughter cells
• Fragmentation: Spirogyra; body breaks; each piece regenerates into complete organism
• Regeneration: Planaria; cut into pieces; each grows; specialised cells called neoblasts perform this

Budding and Spores

• Budding: Hydra; small outgrowth (bud) develops from parent body; detaches as new organism
• Spore formation: Rhizopus (bread mould), ferns; small, light spores; dispersed by air; germinate in favourable conditions
• Vegetative propagation: potato eyes, ginger rhizomes, onion bulbs, sugarcane stem; gives rise to genetically identical plants

Sexual Reproduction in Flowering Plants

• Stamen: anther (pollen) + filament; Pistil: stigma + style + ovary (contains ovule)
• Pollination: transfer of pollen; self (same flower) or cross (different flower)
• Fertilisation: pollen germinates on stigma; pollen tube grows to ovule; male gamete fuses with egg → zygote → embryo → seed

Human Reproductive System

• Male: testes (sperm + testosterone), epididymis, vas deferens, prostate, seminal vesicles, urethra
• Female: ovaries, fallopian tubes, uterus, vagina
• Puberty: hormones trigger development; menarche (first menstruation) in girls; voice change, body hair in boys

Reproductive Health

• Contraception: prevents unwanted pregnancy; barrier methods (condom), hormonal (pill), IUD, surgical (vasectomy, tubectomy)
• STIs: sexually transmitted infections; gonorrhoea, syphilis (bacterial, treatable); HIV/AIDS (viral, not curable)
• CBSE focus: types of contraceptives and their mechanisms; need for reproductive health education

CBSE Exam Tips

• Reproduction: 5–6 marks; asexual types with examples, male/female reproductive system diagram
• Difference: sexual vs asexual reproduction — CBSE frequently asks 3 differences
• Draw: male or female reproductive system with labels; cross-section of flower