Animal Phyla

 

General Characters Of Phylum Porifera

Porifera

The Water Dwellers

Poriferans are multicellular, asymmetrical, or radially symmetrical animals having pores on their body and skeleton made up of spicules. They are exclusively aquatic animals.

General Characters Of Phylum Porifera

1. Poriferans are mostly marine animals. One specie belongs to fresh water. 
2. They lack true tissues and organs.
3. They are sessile animals.
4. Poriferans bodies have numerous pores, which are generally of 2 types, ie, “ostia” by which water enters the body and “osculum” by which water leaves the body.
5. Their body have two layers of cells. The outer layer is ectoder and inner layer is endoderm. The two layers are separated by mesenchyme.
6. The inner cavity of a poriferan body is called a “spongocoele”. 
7. They have skeletons made up of spicules. These is speak use can be made up of calcium carbonate silica and protein.
8. Digestion is intracellular.
9. There are no excretory or respiratory organs.
10. Most of the sponges are hermaphrodite, while some members have separate sexes.
11. Reproduction is by asxeual and sexual methods both.  Asexually, they reproduce by fragmentation, budding, or gemmules. 
12. Sponges have high regeneration power.
13. The sponges have 3 main body types: Ascon, Sycon, and Leucon