Chapter 7 — How do Organisms Reproduce?

NCERT Class 10 Science Chapter 7 explains how organisms reproduce using asexual methods (fission, budding, fragmentation, regeneration, vegetative propagation, spore formation) and sexual reproduction, covering flowering plants and the human reproductive system including puberty, fertilisation, and contraception.

Chapter 7 of NCERT Class 10 Science explains why and how organisms reproduce. Reproduction involves copying DNA and creating new cellular apparatus. Asexual reproduction — including binary fission in Amoeba, budding in Hydra, fragmentation in Spirogyra, vegetative propagation in plants, and spore formation in Rhizopus — creates new individuals from a single parent. Sexual reproduction combines DNA from two individuals via gametes, generating greater variation that aids species survival. The chapter covers pollination and fertilisation in flowering plants, puberty and the male and female human reproductive systems, menstruation, the role of the placenta, and contraceptive methods.

1. 01DNA copying is the fundamental event in reproduction; copies are similar but not identical, producing variations that drive evolution.
2. 02Asexual reproduction modes include binary fission (Amoeba, bacteria), multiple fission (Plasmodium), budding (Hydra, yeast), fragmentation (Spirogyra), regeneration (Planaria), vegetative propagation (potato, Bryophyllum), and spore formation (Rhizopus).
3. 03In flowering plants, pollen transfers from stamen to stigma (pollination), followed by fertilisation in the ovary to form a zygote that develops into a seed inside a fruit.
4. 04Sperms are produced in the testes (located in the scrotum for lower temperature); eggs mature in the ovaries, with one released monthly through the fallopian tube to the uterus.
5. 05The placenta — a disc embedded in the uterine wall — supplies glucose and oxygen from the mother's blood to the developing embryo and removes waste products.
6. 06If the egg is not fertilised, the thickened uterine lining breaks down and is expelled as blood and mucus over roughly two to eight days — this is menstruation.