Question

In some species, parthenogenesis may alternate with sexual reproduction. This process is called as
A. Complete parthenogenesis
B. Incomplete or cyclic parthenogenesis
C. Both A and B
D. Alternate generation

Answer 1

Parthenogenesis is the mode of reproduction in some animals that involves egg development without fertilization. This phenomenon is seen in different groups of animals such as insects, many crustaceans, rotifers, some gastropod molluscs and in some vertebrates like desert lizards, etc.

Complete answer:
There are mainly two types of parthenogenesis- natural and artificial parthenogenesis.

Natural parthenogenesis occurs naturally, regularly and constantly in the life cycles of certain animals. It is further divided into two types-
Complete parthenogenesis- In some insects, there are no males in the species and also the sexual phase is absent in their life cycle. They depend exclusively on self-reproduction through parthenogenesis. It is found in some species of rotifers, cockroaches, grasshoppers, moths, earthworms, etc.
Incomplete parthenogenesis- It involves two generations in the life cycles of insects- the sexual generation and parthenogenetic generation. Both of these generations alternate with each other. In such cases, the diploid eggs produce males and this type of parthenogenesis is known as cyclic or incomplete parthenogenesis. For example, in honey bees, fertilized eggs give rise to queens and workers and unfertilized eggs develop into drones.
Paedogenetic parthenogenesis- In this case, a new generation of larvae is produced by parthenogenesis. It occurs in sporocysts rediae of liver fluke.
Artificial parthenogenesis- It is the case when the eggs which always develop into young individuals by fertilization may sometimes develop parthenogenetically under artificial conditions. It may be induced by electric shock, UV light, temperature etc.