Chapter 11 — Reproduction — How Life Continues

Chapter 11 of NCERT Class 9 Science (2026-27 'Exploration' edition) covers reproduction — the biological process by which living organisms produce new individuals — exploring asexual reproduction (vegetative propagation, budding, spore formation) and sexual reproduction in plants, animals, and humans.

Reproduction is the biological process by which living beings produce new individuals of their own kind, ensuring life continues on Earth. Chapter 11 covers two main types: asexual reproduction, where a single parent produces genetically identical offspring through methods like vegetative propagation, budding, and spore formation; and sexual reproduction, where two parents contribute genetic material via meiosis, creating variation. The chapter explores pollination and fertilisation in flowering plants, external and internal fertilisation in animals, and the human reproductive system including the menstrual cycle, pregnancy, contraception, and sexually transmitted infections.

1. 01Asexual reproduction involves one parent and produces genetically identical clones via mitosis; methods include vegetative propagation (cutting, grafting, layering, tissue culture), budding in hydra, and spore formation in fungi.
2. 02Sexual reproduction involves two parents; meiosis halves the chromosome number to form gametes (sperm and eggs), and the random mixing of chromosomes during meiosis creates genetic variation among offspring.
3. 03In flowering plants, the stamen (male) produces pollen grains and the pistil (female) contains the ovary with ovules; pollination transfers pollen from anther to stigma via wind, water, insects, or birds, after which fertilisation forms a zygote that develops into a seed inside the fruit.
4. 04In animals, external fertilisation occurs outside the body (fish, frogs) producing many eggs with low survival rates, while internal fertilisation occurs inside the female (reptiles, birds, mammals) with fewer eggs and higher survival rates.
5. 05In humans, one mature egg is released monthly from the ovaries (ovulation); if fertilised by sperm in the oviduct, a zygote forms, implants in the uterus, and pregnancy of about nine months begins divided into three trimesters; if unfertilised, the uterine lining sheds as menstruation.
6. 06Contraceptive methods include barrier methods (condoms), oral pills that alter hormone levels, intra-uterine devices (Copper-T), and surgical methods; condoms also prevent sexually transmitted infections (STIs) such as HIV, gonorrhoea, and syphilis.