Question

Explain asexual reproduction in unicellular and multicellular organisms.

Answer 1

Hint: Reproduction is a biological process in which new individuals are formed from their parents. To continue the progeny of an organism or the species of an organism, reproduction is necessary for the survival of living things. Reproduction prevents the extinction of species and leads to evolution in the long run.

Complete step by step answer:
In asexual reproduction, the fusion of gametes does not take place and there is no change in the number of chromosomes. A single parent is involved in sexual reproduction. The offspring produced by sexual reproduction is similar to the parent.
Asexual reproduction in the unicellular organism:
Unicellular organisms are the organisms having a single cell. They reproduce by the mode of asexual reproduction and involves single parents to produce their offspring. Binary fission takes place in unicellular organisms. Binary fission is seen in amoeba and paramecium. The division of the cell into two halves which develop into two individuals is known as binary fission. Budding in hydra is another example of sexual reproduction in unicellular organisms. A bud is an outgrowth of the cell which on maturation detaches from the parent organism and develops into a new organism.
Asexual reproduction in multicellular organisms:
In multicellular organisms, asexual reproduction is seen by vegetative propagation. Vegetative propagation is the form of reproduction where the part of the plant beside the seed is used for producing a new plant. Vegetative propagation can be done in two ways i.e. artificial and natural. in natural vegetative propagation, the plant grows itself without any human interference. It can be seen in adventitious roots. The plant can emerge from the stem, leaves or root of the parent plant. Artificial vegetative propagation is carried out in the field or laboratory by humans.
Artificial vegetative propagation can be done by cutting, grafting, and layering in plants. In the method of grafting, a plant cutting is attached to the stem of another plant that is rooted in the ground. In layering, the plant stem is bent on the ground and is covered with soil. In cutting, a part of the plant that has a stem or a leaf is cut and planted in soil. Humans cannot reproduce sexually. In some species, females do not require a male to produce offspring. Parthenogenesis is one form of a sexual reproduction in which females lay unfertilised eggs that develop into clones.

Note: Male produces the smallest human cell in the body which is about 5 micrometres in size i.e. the sperm cell. Female produces the largest human cell in the body which is about 120 micrometers in diameter i.e. ovum’ or egg. Elephants have the longest pregnancies amongst any mammal which is around 2 years.