Parthenogenesis

Parthenogenesis:

• Parthenos – virgin, Genesis- produce
• Development of an egg into a complete individual without fertilization is known as parthenogenesis.
• It was first discovered by Charles Bonnet in 1745.

Types of Parthenogenesis:

Parthenogenesis is of two main types namely, Natural Parthenogenesis and Artificial Parthenogenesis.

A) Natural Parthenogenesis

• In certain animals, parthenogenesis occurs regularly, constantly and naturally in their life cycle and is known as natural parthenogenesis.
• Natural parthenogenesis may be of two types, viz., complete and incomplete.

1. Complete parthenogenesis is the only form of reproduction in certain animals and there is no biparental sexual reproduction. There are no male organisms and so, such individuals are represented by females only.
2. Incomplete parthenogenesis is found in some animals in which both sexual reproduction and parthenogenesis occur. e.g. In honeybees; fertilized eggs (zygotes) develop into queens and workers, whereas unfertilized eggs develop into drones (male).
3. In paedogenetic parthenogenesis (paedogenesis) the larvae produce a new generation of larvae by parthenogenesis. It occurs in the sporocysts and Redia larvae of liver fluke. It is also seen in the larvae of some insects. e.g. Gall fly.

B) Artificial Parthenogenesis:

In artificial parthenogenesis, the unfertilized egg (ovum) is induced to develop into a complete individual by physical or chemical stimuli. e.g., Annelid and seaurchin eggs.