How living things produce new generations
Reproduction allows organisms to produce offspring and continue their species. Asexual reproduction involves one parent and produces genetically identical offspring through methods such as binary fission in Amoeba, budding in yeast and Hydra, fragmentation in Spirogyra, spore formation in Rhizopus and vegetative propagation in potato and Bryophyllum. Sexual reproduction involves the fusion of male and female gametes and produces offspring with variation.
In flowering plants, stamens produce pollen and the pistil contains ovules. Pollination transfers pollen to the stigma, and double fertilisation forms both a zygote and the endosperm; the ovary develops into a fruit. In humans, testes produce sperm and ovaries release eggs. Fertilisation occurs in the fallopian tube, and the embryo implants in the uterus, nourished through the placenta. In Class 12, you study gametogenesis, the menstrual cycle controlled by hormones such as FSH, LH, oestrogen and progesterone, and reproductive health, including contraception, prevention of sexually transmitted infections and assisted reproductive technologies such as IVF.
Why it matters
Reproduction explains how farmers grow crops from cuttings and grafting, how seeds and fruits form, and how families plan their size safely. Awareness of reproductive health and hygiene protects people from infections and supports informed decisions. Assisted reproductive technologies help couples who face infertility. The topic links to genetics, evolution and human health.
Key terms
- Asexual reproduction
- Reproduction involving a single parent that produces genetically identical offspring.
- Pollination
- The transfer of pollen grains from the anther to the stigma of a flower.
- Double fertilisation
- In flowering plants, the fusion of one male gamete with the egg and another with the polar nuclei.
- Placenta
- The organ that connects the developing embryo to the mother’s uterus for nourishment.