What it does
In asexual reproduction a single parent makes offspring without any partner, and the offspring are copies of the parent. This page shows six ways it happens, each as a short moving drawing you can step through:
- Binary fission (Amoeba, bacteria): the nucleus divides, then the cell pinches into two.
- Multiple fission (Plasmodium): inside a protective cyst the nucleus divides many times, then many small cells are released at once.
- Budding (Hydra, yeast): a bump grows on the side, becomes a small copy and breaks off.
- Fragmentation (Spirogyra): a filament breaks into pieces and each grows into a new filament.
- Regeneration (Planaria): each cut piece grows back the parts it is missing.
- Spore formation (Rhizopus, bread mould): a spore case bursts and light spores drift away to grow somewhere damp.
A second panel shows why fission is so powerful: one cell becomes 2, 4, 8, 16 … With a doubling time of 20 minutes, a single bacterium could pass a million in under seven hours, if food and space lasted.
It follows the Class 9 science chapter Reproduction: How Life Continues and the Class 10 chapter on how organisms reproduce. How the nucleus copies itself is in cell division, and sexual reproduction in flowers is in flower pollination.
How to use it
- Pick a way of reproducing.
- Move the Stage slider, or press Play. The caption says what is happening.
- In Population from fission, set the starting cells N₀, the doubling time T and the time t. Tick Log scale to see big numbers clearly.
A worked example
Start with N₀ = 1, T = 20 min, t = 180 min. That is 180 ÷ 20 = 9 doublings, so N = 1 × 2⁹ = 512 cells. Reaching a million needs log₂(1 000 000) ≈ 19.9 doublings, about 399 minutes.
Tips
- Binary fission gives 2 cells; multiple fission gives many at once.
- On a log scale, steady doubling is a straight line.
- Real populations slow down when food or space runs out.
FAQ
Why do living things also reproduce sexually? Mixing two parents’ genes makes varied offspring, which helps a species survive when conditions change.
Is this the NCERT book? No. It covers the same topic with fibub’s own drawings. fibub is not part of NCERT.
Where the numbers come from
- Modes of asexual reproduction and the examples (Amoeba, Plasmodium, Hydra, yeast, Spirogyra, Planaria, Rhizopus) are standard school biology. Drawings and text are fibub's own; a teaching model, not to scale.
- Growth by doubling N = N₀·2^(t/T) checked by hand and in tests/sci-tools/reproduction-modes.mjs (20-minute doubling: 512 cells after 3 hours; a million after about 399 minutes).
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-09.