Enlist the main characteristics & examples of phylum Porifera.
The main characteristics of phylum Porifera are: - (i) They are commonly known as sponges. (ii) They are generally marine. (iii) Their body is diploblastic and bilaterally symmetrical. (iv) They possess a water transport mechanism. (v) They are extremely primitive multicellular animals with a cellular level of organisation. (vi) Water can enter by pores called Ostia in the body wall directly or through the canal into the spongocoel. It goes out through the osculum. It is known as the canal system. (vii) The body is supported by a skeleton that consists of spicules (viii) Sexes are not separate. (ix) They reproduce asexually by fragmentation. (x) They also reproduce sexually by the formation of gametes. (xi) Fertilization is internal. (xii) Example- Euplectella, Spongilla, Sycon, Euspongia etc.
