NCERT Solutions for Class 9th Science Chapter 11 Reproduction: How Life Continues
Updated on 2026-09-19
About this chapter
Asexual reproduction needs one parent and uses mitosis , so the offspring are genetically identical clones — budding in yeast and hydra, spore formation in fungi, and vegetative propagation (cutting, grafting, layering, tissue culture) in plants. Sexual reproduction needs two parents. Meiosis halves the chromosome number (46 → 23 in humans) to make gametes, and fertilisation restores it, so the number stays constant generation after generation. Because the chromosomes of each pair separate independently, n pairs give 2 n kinds of gamete — 8 for the three bead pairs of Activity 11.4, and 2 23 = 8,388,608 for a human. This is where variation comes from. In a flower, the stamen (filament + anther) makes pollen and the pistil (stigma + style + ovary) holds the ovules. Pollination moves pollen
- Chapter opener
- Let us explore
- .1 Asexual Reproduction
- Let us experiment
- Fungi and society
- .2.2 Sexual reproduction in flowering plants
- Let us investigate
- .2.3 How does the process of pollination occur in flowers?
- .2.4 Pollination strategies and reproductive success
- Let us find out
Quick revision
| Term | What it means | Where it happens / typical value | Where it appears in the chapter |
|---|---|---|---|
| Asexual reproduction | One parent; offspring genetically identical to it | Runs on mitosis | Bacteria, amoeba, yeast, hydra, potato, ginger — 11.1 |
| Vegetative propagation | A new plant grows from a vegetative (growing) part of the old one | Cutting, grafting, layering, tissue culture | Bryophyllum leaf (Fig. 11.1); Activity 11.1 |
| Budding | Repeated cell division at one spot makes an outgrowth that separates and lives on its own | Yeast, hydra | Fig. 11.6, Fig. 11.7; Activity 11.2 |
| Spore formation | Light, usually single-celled spores made in a sac or on a swollen vesicle | Fungi; need warmth (25 – 35 °C) and moisture | Rhizopus, Aspergillus (Fig. 11.8); Activity 11.3 |
| Mitosis | Division giving two daughter cells with the same chromosome number as the parent | Growth, repair, all asexual reproduction | 11.1 – ‘offspring are clones’ |
| Meiosis | Division that halves the chromosome number | Testes and ovaries; anther and ovule. 46 → 23 in humans | 11.2.1; Activity 11.4 |
| Gamete | A haploid reproductive cell | Sperm — small, motile, no stored food. Egg — large, non-motile, with yolk | Table 11.5 |
| Pollination | Transfer of pollen from anther to stigma | Self- or cross-; agents are wind, water, insects, birds | 11.2.3, 11.2.4; Activity 11.6 |
| Fertilisation | Fusion of the male gamete with the egg to form a zygote | In the ovule (plants); in the oviduct (humans) | Fig. 11.14, Fig. 11.20 |
| Fruit and seed | The ovary ripens into the fruit; each ovule ripens into a seed | After fertilisation in a flowering plant | Fig. 11.15; 11.2.5 |
| External vs internal fertilisation | Gametes meet outside the body in water, or inside the female body | Frog 5,000 – 50,000 eggs, survival low; bird 1 – 15 eggs, survival moderate to high | Table 11.4; 11.3, 11.4 |
| Menstrual cycle | Ovulation, thickening of the uterine lining, then shedding if there is no implantation | 21 – 35 days (often 28); menstruation 3 – 7 days; ovulation about day 14 | Fig. 11.21; 11.5.5, 11.5.6 |
Exercises
- Chapter opener — Think It Over Page 208
- Let us explore — Activity 11.1 Page 209 – 210
- Let us explore — Activity 11.2 Page 211
- .1 Asexual Reproduction — In-text Questions Page 21111
- Let us experiment — Activity 11.3 Page 211 – 212
- .1 Asexual Reproduction — In-text Questions Page 21211
- Fungi and society — Bridging Science and Society Page 212
- .2.1 How does meiosis help create variations in sexual reproduction? — In-text Questions Page 21311
- Let us explore — Activity 11.4 Page 213
- .2.2 Sexual reproduction in flowering plants — In-text Questions Page 21411
- Let us explore — Activity 11.5 Page 214 – 215
- .2.2 Sexual reproduction in flowering plants — In-text Questions Page 21511
- Let us investigate — Activity 11.6 Page 215 – 216
- .2.3 How does the process of pollination occur in flowers? — In-text Questions Page 21611
- .2.4 Pollination strategies and reproductive success — In-text Questions Page 21711
- Let us find out — Activity 11.7 Page 217
- .2.5 Fertilisation and seed formation — Pause and Ponder Page 21711
- .3 Sexual Reproduction in Animals — Pause and Ponder Page 21811
- .5.6 What happens when an egg is not fertilised? — Threads of Curiosity Page 22111
- .5.7 Pregnancy and childbirth — Pause and Ponder Page 22211
- .5.10 How can unwanted pregnancies and infections be prevented? — Pause and Ponder Page 22311
- .5.10 How can unwanted pregnancies and infections be prevented? — Pause and Ponder Page 22411
- End-of-chapter questions — Revise, Reflect, Refine Page 225 – 226
- Project work — The Journey Beyond Page 227
- An open question — The Quest Continues … Page 227