Reproduction in Living Organisms
Reproduction is a biological process that results in the formation of new individuals of the same kind with slight genetic structural and physiological variations.
Reproduction is essential for organisms as it enables continuity of the species from generation to generation.
Reproduction is of two types:
- Asexual Reproduction
- Sexual Reproduction
In this type of reproduction, a single organism is capable of producing its own kind. In this type of reproduction participation of both gamete is not required and the individual produces are genetically identical or the exact copy of the parent. Asexual reproduction involves rejuvenation of protoplast and formation of specialized asexual reproduction structure by the parent body which grows into new individuals. They are also known as Clone.
Various Methods of Asexual Reproduction
It is the most common method of asexual reproduction which is basically of two types:
The formation of two individuals forms a single parent. The binary Fission may be irregular, transverse as well as longitudinal.
Ex: Paramecium, Amoeba, etc.
The formation of multiple nuclei is known as multiple Fission basically it occurs during unfavorable conditions it is easily found in amoeba. During this phase, amoeba forms a three-layered covering around their body which is known as a cyst. A cyst is lighter in weight so easily cyst can easily move from one place to another. Inside the cyst, the nucleus of amoeba divides many times and forms multiple spores. These spores are known as pseudopodiospores.
After getting the favorable environment cyst dissolves and the spores and the pseudopodiospores became free and form new amoeba.
In this process the protoplast bulges out in the form of a bid that grows, taking nutrition from the mother organism and after the full development, it is separated from the mother cell.
Ex: Hydra, Yeast, etc.
The power of the replacement of the lost part is known as regeneration.
Ex: Amoeba, etc.
It is generally found in Ulothriux, Sporangia, and some filamentous algae. In this process, the thallus breaks into small fragments, and each fragment can grow into a new thallus (body) individuals.
In this process, the motile or non-motile spore is formed which germinate directly to the new individuals.
Ex: Chlamydomonas, etc.
In some fungi spore formation of sporenzio and conidia. Ex: Aspergillus, etc.
This process occurs in some freshwater and marine spore by the accumulation of gemmules. Basically, gemmule is exogenous buds and formed by the accumulation of archaeocytes cells with food reserve material.
Vegetative Propagation in Plants
Regeneration of new plants from a part of the vegetative organ is called vegetative propagation or vegetative propagation or vegetative reproduction.
Natural Vegetative Propagation
Through Underground Stem
Rhizome– Ginger (Zingiber officinale), Turmeric (Curcuma domestica)
Tuber– Potato (Solanum tuberosum)
Bulb– Onion (Allium cepa)
Corn– Saffron (Crocus sativa), Taro (Colocasia antiquorum)
Runner– Doob grass (Cynodon dactylon)
Offset– Water hyacinth (Eichhornia crassipes)
Sucker– Mint (Mentha), Strawberry (Frangira)
Sweet potato– Murray
When the lower parts of inflorescence and modified into a small multicellular structure known as bulbils. They fall on the ground and grow into new plants.
Example: Globba bulbifera.
Artificial Vegetative Propagation
This is a common method done by the gardeners in which a portion of leaf, root or stem known as cutting. Cutting is taken out and rooted in the soil. Example: Coleus, Bougainvillea.
Basically, it is found in Jasmine, Strawberry, Apple, etc. In this technique, the lower branch of the plant is bent down inside the moist soil. In such a way that the growing tips remain above the surface, this new bent branch is called a layer.