Briefly explain Gemmule Formation in sponges. Write its significance. (SHORT ANSWER QUESTIONS) (2MARK)

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Answer :- Gemmules are dormant structures produced asexually by the formation of specialised exogenous buds, at certain times of the year, in many freshwater sponge species and a few Marine species. To begin, archaeocytes accumulate nutrients by phagocytizing other cells and then cluster together within the sponge. Certain cells surrounding each cluster than secrete a thick, protective covering ; the formed structure is termed gemmule. After gemmule formation, the original sponge disintegrates. In favourable conditions the floating gemmules produce a new sponge.

Significance

Gemmules are far more resistance to desiccation, freezing and anoxia (lack of oxygen) then the sponges that produce them. Under appropriate environmental conditions, the living cells leave the Gemmule through a narrow escape opening and differentiate to a form functional sponge. 

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