Asexual Reproduction in Animals
Reproduction may be referred as production of true copies. Most of the animals that are quite familiar to us generate male and female gametes (sperms and eggs). These gametes unite together to form a zygote that subsequently develops into an adult that is a copy of the parents. This type of reproduction is called sexual reproduction. There are also a large number of animals, specifically among non-chordates, which reproduce from body parts other than gametes. This does not include sex or sex-cells or meiotic division. It basically involves both growth and regeneration of missing parts. Such type of reproduction is categorised as asexual reproduction and it is extremely common among coelenterates, planarians, polychaetes and oligochaetes. Asexual reproduction is as well called vegetative reproduction; this is because it involves some body part or any special unit generated by it, not related to the gamete-producing organs (ovaries and testes). Actually, asexual reproduction is the most primitive one -the first organisms that evolved on the earth were protistans and they possibly just divided into two - the simplest form of asexual reproduction. Even today, this is the most general type of reproduction among protistans.
Main forms of asexual reproduction
The following are the main types of asexual reproduction.
- Fragmentation Budding
- Binary fission
- Strobilation
- Multiple fission
- Formation of special units (or bodies)