Please explain about phylum porifera?Give main points? And give examples of this phylum?

General characteristics of Phylum Porifera

1. Kingdom: Animalia
2. Habitat: Aquatic, mostly marine, few are terrestrial
3. Habit: They are solitary or colonial.
4. Grade of organization: cellular grade of body
5. Shape: Body shape is variable, mostly cylinder shaped
6. Symmetry: Asymmetrical or radially symmetrical.
7. Germ layer: Diploblastic animals. The adult body wall contains two layers, outer dermal layer and inner gastral layer. In between these two layers, there is a gelatinous and non-cellular mesoglea containing numerous free amoeboid cells.
8. Coelom: Absent; acoelomate but spongocoel is present
9. Surface of the body has numerous perforation called ostia (for the entry of water) and a large pore at the apex called osculum (for the exit of water).
10. Water canal system present
11. Endoskeleton: Either calcareous spicules (calcium carbonate) or siliceous spicules (silica) or sponging fibers (protein).
12. Nutrition: holozoic
13. Digestion: Intracellular
14. Nervous system: absent
15. Circulatory system: absent
16. Reproduction:

• Asexual: by budding or gemmule or regeneration
• Sexual: gamatic fusion

1. Fertilization: Internal