Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction, are either from a single cell or from a multicellular organism, it inherits the genes of their single parent. It is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many eukaryotic organisms including plants, animals, and fungi can also reproduce asexually. Invertebrates, the most common form of asexual reproduction is parthenogenesis which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited.
Types of Asexual Reproduction System
- Binary Fission: It is one of the simplest and uncomplicated methods. The parent cell divides into two, each daughter cell carrying a nucleus of its own that is genetically identical to the parent. The cytoplasm also divides leading to two equal-sized daughter cells. The process repeats itself and the daughter cells grow and further divide.
- Fragmentation: It is exhibited by organisms such as spirogyra, planaria, etc. The parent body divides into several fragments and each fragment develops into a new organism.
- Regeneration: Regeneration is the power of growing a new organism from the lost body part. For eg., when a lizard loses its tail, a new tail grows. This is because the specialized cells present in the organism can differentiate and grow into a new individual. Organisms like hydra and planaria exhibit regeneration.
- Budding: Budding is the process of producing an individual through the buds that develop on the parent body. Hydra is an organism that reproduces by budding. The bud derives nutrition and shelter from the parent organism and detaches once it is fully grown.
- Vegetative Propagation: In plants occurs through their vegetative parts such as leaves, roots, stems, and buds. This is called vegetative propagation. For Ex: Potato tubers, runners/stolon, onion bulbs, etc., all reproduce through vegetative propagation.
- Spore Formation: Spore formation is another means of asexual reproduction. During unfavorable conditions, the organism develops sac-like structures called sporangium that contain spores. When the conditions are favorable, the sporangium burst opens and spores are released that germinate to give rise to new organisms.
- Single parent involved.
- No fertilization or gamete formation takes place.
- This process of reproduction occurs in a very short time.
- The organisms multiply and grow rapidly.
- The offspring is genetically similar.
- Mates are not required.
- The process of reproduction is rapid.
- An enormous number of organisms can be produced in very little time.
- Positive genetic influences pass on to successive generations.
- It occurs in various environments.
- Lack of diversity. Since the offsprings are genetically identical to the parent they are more susceptible to the same diseases and nutrient deficiencies as the parent. All the negative mutations persist for generations.
- They are unable to adapt to the changing environment.
- A single change in the environment would eliminate the entire species.