Reproduction in lower and higher organisms Class 12th Biology Maharashtra board
Online Notes | PDF | Free | Short notes | Sexual reproduction in animals
Reproduction
- Reproduction is defined as the biological process of creating a new organism from the same pre-existing organism.
- By reproduction, the species can survive longer.
- Reproduction in animals occurs mainly in two ways, namely asexual and sexual.
Asexual reproduction in animals
- Common and primitive method in animals.
- Meiosis or gamete formation and fertilization do not occur in asexual reproduction.
- Single parents are involved and offspring are the same as parents. It is also called a clone.
- E.g. Gemmule formation and budding.
Gemmule formation
- The gemmule is an internal bud that forms only in the sponge. In sponges, this method of asexual reproduction is adopted under adverse conditions.
- Thus gemmule is an aggregation of asexually produced mass or dormant archaeocyte cells. They develop into a new organism.
- Around archeology, amoebocytes form a thick resistant membrane layer.
- When favorable conditions return, the gems germinate and develop into new ones.
Example: Spongela
Budding:
- This is a simple method of asexual reproduction that occurs in coalentrates (hydra and coral) and some colonic ascidians.
- A bud, that is, towards the basal end of the body, produces a small growth in the hydra.
- The bud develops into a bud that grows and forms a tent and develops (transforms) into a new person.
- This young Hydra then becomes detached from the parent and becomes a separate organism.
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