List four modes of asexual reproduction.
List four modes of asexual reproduction other than fission in the living organisms.
Four modes of asexual reproduction are:-
1. Binary Fission
In binary fission, a single cell divides into two halves. Some of the organisms that divide by binary fission are bacteria and Amoeba.
It involves the formation of a new individual from a protrusion called a bud. It is very common in plants, yeasts and lower level animals such as Hydra.
In Hydra, cells divide rapidly at a specific site and develop as an outgrowth called a bud. This bud, while attached to the parent plant, develops into a small individual. When this individual becomes large enough, it detaches itself from the parent body to exist independently.
3. Multiple Fission
In multiple fission, a single cell divides into many daughter cells simultaneously, for example, Plasmodium.
Fragmentation is the unintentional cutting up of the body of an organism in which each part grows into a different organism. It is most commonly seen in some annelids and fungi.
5. Spore formation
Spores are asexual reproductive bodies enclosed in a thick-walled structure called sporangium, which can tide over unfavourable conditions such as extreme heat, dryness, acidity, and so on. Spore formation is a common method of asexual reproduction in many lower forms of life such as algae, bacteria and fungi.
Under favourable conditions, the spores are released by the breaking of the thick wall of the sporangium. The spores then germinate into new individuals. In fungi, sporangia burst and release spores. By this method of asexual reproduction, organisms can overcome unfavourable conditions. Some fungi, e.g., Rhizopus and Mucor reproduce by producing spores.
6. Vegetative Propagation in Plants
The vegetative parts of a plant such as the root, stem, leaf, etc., can produce new plants. You must have seen gardeners taking cuttings from the stem of a rose plant and planting them in the soil. Under suitable conditions, the cuttings grow into new rose plants.
Vegetative propagation is common in plants like orchids, ornamental plants and grasses. Plants such as banana, rose, jasmine, etc., which do not produce seeds, can be grown by vegetative methods. The new plants are genetically similar to and bear the characteristics of the parent plant.