Animal Kingdom - Notes | Class 11 | Part 2: Porifera

Phylum Porifera (Sponges): General Characters

• Grades of Organization: Cellular grade.
• Symmetry: Asymmetrical. Some are radial.
• Coelom: Acoelomate
• Habit and Habitat: Aquatic (mostly marine). Sedentary. Solitary/colonial.
• Digestive System: Absent. Intracellular digestion.
• Respiratory System: Absent
• Circulatory System: Absent
• Reproduction:
• Asexual (fragmentation) & Sexual.
• Hermaphrodite (Monoecious): Male and female sex organs are seen in same individual.
• Internal fertilization.
• Development is indirect.


• Unique Features:
• Water canal (water transport) system. Millions of ostia (pores).
• Water canal system: Here, water enters through minute pores (ostia) in the body wall into a central cavity (spongocoel), from where it goes out through osculum. Canal system is used for food gathering, gas exchange and removal of wastes.
• Spongocoel & canals are lined with choanocytes (collar cells).
• Body is supported by spicules and spongin fibres.
• Examples:
• Sycon (Scypha)
• Spongilla (fresh water sponge)
• Euspongia (Bath sponge)

Select a Topic 👇

1. Basis of Classification 2. Porifera 3. Cnidaria 4. Ctenophora 5. Platyhelminthes 6. Aschelminthes 7. Annelida 8. Arthropoda 9. Mollusca 10. Echinodermata 11. Hemichordata 12. Chordata - up to Sub phylum Vertebrata 13. Chordata - Cyclostomata, Pisces 14. Chordata - Tetrapoda

Download PDF