Question

write an essay on polymorphism in hydrozoa​

Answer 1

●Definition of Polymorphism:

Polymorphism may be defined as the “phenom­enon of existence of different physiological and morphological forms represented by an extensive range of variation within a single species”.

It may be defined in another way, poly­morphism means “the existence of indi­viduals (zooids) of a single species in more than one forms and functions.”

●Causes of Polymorphism:

Polymorphism is due to the division of labour, diversifica­tion of forms and specialization. Two general types of interactions, viz., co-operation and disoperation are exhibited by the members of an animal association.

In the colonial forms, disoperation ceases gradually and is replaced by co-operation. Finally the whole colony appears as a single individual, and the zooids function collectively for the inter­est of the colony (Barrington 1979).