Question

QI. Explain the classification of Phylum Porifera upto class with
examples.​

Answer 1

Answer:

Classification of Phylum Porifera.

Phylum Porifera is classified into three classes:-

• Calcarea

1. They are found in marine, shallow, and coastal water.
2. Their skeleton is composed of calcareous spicules made of calcium carbonate.
3. The body is cylindrical and exhibits radial symmetry.
4. The body organization is asconoid, syconoid, or leuconoid.

Eg., Clathrina, Scypha

• Hexactinellids

1. They are found in marine and the deep sea.
2. The skeleton is made up of six-rayed siliceous spicules.
3. The body is cylindrical in shape and exhibit radial symmetry.
4. The canal system is Sycon or Leucon.

Eg., Euplectella, Hyalonema

• Desmospongiae

1. They are found in marine or freshwater.
2. The body is asymmetrical and cylindrical in shape.
3. The canal system is a leuconoid type.
4. The skeleton comprises of spongin fibres, siliceous spicules, which are monoaxon and triaxon.

Eg: Spongia, Spongilla, etc.