PHYLUM PORIFERA (Sponges) - CLASS 11 BIOLOGY NOTES
📌 General Characteristics
● Simplest multicellular animals.
● Commonly called sponges.
● Aquatic (mostly marine, few freshwater).
● Sessile (non-motile) and attached to substratum.
● Asymmetrical or radially symmetrical body.
● Cellular level of organization (no true tissues or organs).
● Body is perforated with numerous pores -> Ostia (inlet) and Osculum (outlet).
● Body wall with two layers: outer pinacoderm (epidermis), inner choanoderm (collar cells).
🔁 Canal System
● Unique to Porifera.
● Water flows through ostia -> spongocoel -> osculum.
● Helps in respiration, nutrition, excretion, and reproduction.
● Lined with choanocytes (collar cells) that help in water circulation and food capture.
🍽 Nutrition
● Filter feeders.
● Intracellular digestion (inside food vacuoles of choanocytes).
📌 General Characteristics
● Simplest multicellular animals.
● Commonly called sponges.
● Aquatic (mostly marine, few freshwater).
● Sessile (non-motile) and attached to substratum.
● Asymmetrical or radially symmetrical body.
● Cellular level of organization (no true tissues or organs).
● Body is perforated with numerous pores -> Ostia (inlet) and Osculum (outlet).
● Body wall with two layers: outer pinacoderm (epidermis), inner choanoderm (collar cells).
🔁 Canal System
● Unique to Porifera.
● Water flows through ostia -> spongocoel -> osculum.
● Helps in respiration, nutrition, excretion, and reproduction.
● Lined with choanocytes (collar cells) that help in water circulation and food capture.
🍽 Nutrition
● Filter feeders.
● Intracellular digestion (inside food vacuoles of choanocytes).
