explain with examples types of asexual reproduction in unicellular organism
Answers
Explanation:
Asexual reproduction is a process in which new organism is produced from a single parent without the involvement of gametes or sex cells. Many unicellular and multicellular organisms reproduce asexually. In this process, parent organism either splits or a part of parent organism separates to form a new organism. In this reproduction, certain cells of the parent undergo mitotic cell division so that two or more new organisms are formed.
Jagranjosh
There are six types of asexual reproduction. They are:
1) Fission
2) Budding
3) Spore formation
4) Regeneration
Fission
5) Fragmentation
6) Vegetative propagation
Fission
In fission, unicellular organism splits to form new organisms. It is a process of reproduction in organisms such as protozoa and many bacteria. There are two types of fission:
Binary Fission
In binary fission, the parent cell divides into two after reaching a point where it has fully grown. In this process, after splitting parent cell do not exist and two new organisms are formed.
Examples of unicellular organisms that undergo binary fission are amoeba, paramecium, Leishmania etc.
Binary Fission - In binary fission, the parent cell divides either transversely or longitudinally into two equal halves called daughter cells. For example, Amoeba divides transversely and Leishmania divides longitudinally.
Multiple Fission - In multiple fission, the parent cell divides into multiple daughter cells at same time. For example, Sporozoans.
Budding - In budding, organisms develop bud in their body surface which later develops into a separate individual. For example, Budding Yeast.
Fragmentation - It involves breaking of parent organism into two or many fragments. Each fragment develops into an individual organism. Fragmentation is seen in sea stars which accidentally break their body into fragments. Fragmentation is also observed in annelids, turbellarians and some of the poriferans.
Spirogyra reproduces through fragmentation during which each fragment grows into a new individual.
Regeneration:
Regeneration is also called Morphallaxis. If the organism is cut up, its pieces can grow into separate individuals. Regeneration is commonly seen in Planaria, Hydra.
Regeneration is referred to tissue repair to a normal state. It is the restoration of normal structure and function of the organ. It is actually the replacement of damaged tissue with the same type of cells. Some organisms like lizards have the power of regenerating their tail.
Spore formation:
Spore formation is one form of asexual reproduction. Spore formation is the method of developing new individuals by forming reproductive structures called spores.
A spore is a small spherical or oval structure which protects the future individual in a thick protective covering. Spore germinates on a substratum under favourable conditions. Some organisms like ferns, some groups of fungi reproduce by spore formation.
Fungus reproduces by means of spores. Fungus like bread mould produce spores which germinate on moist organic surfaces. The cottony white mass on bread formed by fungus after spore germination is called a mould. Spores can survive in extreme conditions because of the protective hard coat.
Vegetative propagation:
Vegetative propagation is one mode of asexual reproduction in plants. It is the production of new plants from the vegetative parts of the plant.
Roots, stems and leaves are called the vegetative parts of a plant. Any of these parts serve as vegetative propagules.
Vegetative propagation takes place by different methods like Grafting, Leaf propagation, Root propagation, underground stem propagation etc. Though vegetative reproduction results in the production of varieties of plants, offspring propagated through vegetative propagation are more uniform to parents..
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