Asexual Reproduction
Fission
- Fission is an asexual reproduction that is common in most unicellular organisms.
- When the fission results in two daughter cells, it is binary fission (e.g. paramecium).
- When fission results in many daughter cells, it is called multiple fission (e.g. Plasmodium).
- Planes of fission may be different for different organisms.
Budding
- Budding is a type of asexual reproduction in which a small cyst-like structure is formed on the parent’s body, which gives rise to a new individual.
- Bud may remain attached to the parent (yeast) or may separate and become a new individual (hydra).
Regeneration and Fragmentation
- Regeneration is the process of growing back the lost organ or body part by the organism (e.g. lizard).
- Fragmentation is the process by which an organism gets fragmented into smaller pieces, and each piece grows into a whole new organism.
- E.g. Planaria, Hydra
Spore Formation
Organisms such as fungi make spores that can grow into completely new individuals when dispersed from their fruiting bodies. Spores are produced inside sporangia. They are covered by a thick outer layer that protects them in adverse conditions. When spores get suitable environmental conditions, they germinate and begin to grow.
Vegetative Propagation
- This is a type of asexual reproduction seen in plants.
- The vegetative parts of the plant, like leaves, stems, and roots, give rise to a new plant.
- Vegetative propagation can be artificial or natural.
- Natural vegetative propagation happens through leaves (e.g. bryophyllum), stem (e.g. turmeric, ginger), runners/stolon (e.g. grass runners, strawberry), bulbs ( e.g. onion, lily), etc.
- Artificial methods include cutting, grafting, layering and plant tissue culture.
Parthenogenesis
This is a form of asexual reproduction where the egg develops without fertilization. This process occurs in bees, wasps, ants, aphids, rotifers, etc. Ants, wasps, and bees produce haploid males. Parthenogenesis has been observed in a few vertebrates such as hammerhead sharks, Komodo dragons, and blacktop sharks when the females were isolated from the males.
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