SPONGES
*habitat- all sponges are aquatic, mostly marine, rarely fresh water, solitary or colonial. alla re sessile, attached to the substratum.
*body form- they are vase like, cylinderical, cup shaped, spherical, or disc like. their body is porous,the inhalent pore is called ostia and the exhalent pore is called osculum.
*symmetry.-they are asymmetrical.
*germ layer-diploblastic animal.
sponges are first multicellular diploblastic animal.
*level of organisation-cellular level
*body wall-consist of three layers:-
choanoderm (=gastrel layer)
mesohyl layer (middle layer)
pinacodern(outer layer)
*canal system-three types of canal system are-
asconoid canal system- simplest canal system. e.g.-leucosolenia
syconoid canal system- it is more complex than asconoid system.e.g.- sycon
leuconoid canal system- it is the most complex canal system.e.g.- spongilla
*digestion- interacellular digestion
*respiration- diffusion of gases through plasma membrane.
*excretion-removal of waste is also by diffusion with the help of plasma membrane.
*reproduction- both sexual and asexual(budding and gemmule) reproduction occur.
*development- development is indirect and includes a free swimming larva, the amphiblastula or parenchymula.
*sponges are also called by their common names, some are mentioned here-
Sycon- scypha
Euplectella-the venus' flower basket
Spongia-bath sponge
Spongilla-fresh water sponge
Hyalonema-the glass rope sponge
Leucosolenia- orange pipe sponge
SPONGILLA
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