Question

Describe the different methods of asexual reproduction. Give examples

Answer 1

$\large\bold{1) Fission}$

Fission means division. During asexual reproduction, the parent cell divides into two or more cells. Unicellular organisms show different patterns of cell division according to their cell structure. For example, an amoeba can divide itself into two at any plane but the division in euglena is longitudinal.

Fission can be of two types, namely, binary fission and multiple fission. In binary fission, parent cell divides into two equal halves called daughter cells. Daughter cells are identical to each other and to their parent cell. Organisms like the amoeba, bacteria, euglena, etc., exhibit binary fission.

During multiple fission, organism divides itself into numerous daughter cells. Examples of multiple fission are sporozoans and algae.

$\large\bold{2) Fragmentation}$

Fragmentation is another mode of asexual reproduction. Multi-cellular organisms like planaria, spirogyra, etc. reproduce by fragmentation. The parent body divides into two or more fragments. Later, each fragment develops into a new individual.

$\large\bold{3) Regeneration}$

When a lizard loses its tail, it grows a new one. This is known as regeneration. In many organisms, there are specialized cells, which can differentiate and grow into a new organism. Organisms like hydra and planaria also show regeneration. In these organisms, when the cell divides into numerous pieces, each piece proliferates and differentiates to regenerate new organisms.

$\large\bold{4) Budding}$

Some organisms develop buds on their body. These buds develop into a new individual. This is known as budding. An example is a hydra. From the parent hydra, a bud arises which eventually matures into a new hydra. Once it gets mature, it detaches from the parent body.

$\large\bold{5) Vegetative\: Propagation}$

Plants reproduce asexually through their vegetative parts such as leaves, roots, stem, and buds. This is known as vegetative propagation. For example, onion bulbs, tubers of potato, runners/stolon, etc. Vegetative propagation is much faster than the sexual reproduction in plants. This can be done artificially as well, which is widely employed in horticulture.

Answer 2

In asexual reproduction new plants are produced without the production of seeds. The different methods  of asexual reproduction are vegetative propagation, budding, fragmentation and spore formation.

a) Vegetative propagation – It occurs from the vegetative parts of the plant such as roots, stems,  and leaves.

Root - Sweet potato, Dahlia

Stem - Rose, Sugar cane, Ginger, Potato

Leaves - Bryophyllum

b) Budding – Reproduction in yeast occurs by budding. In this process, a small bulb-like projection is  formed from the yeast cell and is called a bud. The bud gradually grows and gets detached from the  parent cell and develops into a new yeast cell.

c) Fragmentation – It is a common form of asexual reproduction found in algae.

 An Alga breaks up into two or more pieces called fragments. Each of these fragments grows into new  individual. e.g., Spirogyra

d) Spore formation – Spores are single-celled or multi-celled asexual reproductive bodies that are  mostly in spherical shape. Each spore is covered by a hard-protective coat which helps to withstand  unfavourable conditions such as high temperature and low humidity. Under favourable conditions, a  spore germinates and develops into a new individual. e.g., ferns, moss, fungi (Bread mould, mushroom etc).