Question

Phylum Porifera -what kind of body symmetry do they have - what are the unique structures (why are they in this phylum not another) -how do they get their food -where are they found -common examples

Answer 1

Body symmetry of porifera:-Members of porifera are commonly known as sponges.They are generally marine and mostly asymmetrical(any plane that passes through the centre does not divide them into equal halves) animals and occasionally they are radially symmetrical.

Unique structure of porifera:-they are in this phylum because:-

i.The body is supported by a skeleton made up of spicules or spongin fibres.

ii.sexes are not separate(hermaphrodite ),eggs and sperms are produced by the same individual.

iii. Choanocytes or collar cells line the spongocoel and the canals .
iv.sponges have a water transport or canal system.

v.These are primitive multicellular animals and have cellular level of organisation.

They get their food by canal system.water enters through minute pores(ostia) in the body wall into a central cavity ,spongocoel,from where it goes out through osculum.This pathway of water transport is helpful in food gathering.

Porifera comprises sponges they are found in marine habitate in shallow ocean environments ..some are also found in fresh water body(lake).

Common example:-spongilla(fresh water sponge),Euspongia(Bath sponge),sycon(scypha).