Phylum Porifera • Porifera: Porus means holes, ferre means to bear. • Includes sponges • Most primitive true animals • Almost 10,000 marine species of sponges.
Where sponges live Just kidding!
Where Sponges Live • Widely distributed • Intertidal zone to abyssal plain • Found at all latitudes • Benthic
Morphology • Can as small as a bean to the size of a small car. • 3 basic shapes: • Branching • Vase-like • Encrusting • Most lack symmetry
Morphology • Three main grades of sponges. • Ascon: Sacs with a single chamber. • Sycon: Numerous chambers with central opening. • Leucon: Most common. A series of sycon chambers are connected to a large central opening.
Sponge Spicules • Spicules are a sponge’s skeletal network made of calcite or silica (quartz). • These prevent the internal chambers and canals from collapsing. • Some sponges also have a fibrous protein called spongin that serves the same purpose as spicules. • Sponges that are sold (natural ones) have been treated to remove the spicule matrix which makes the sponge softer.
Classes of Sponges • 3 Classes based on spicules. • Calcarea: Sponges with calcitic spicules or porous calcareous walls without spicules. • Demospongea: Skeletons of spongin and siliceous spicules or just siliceous spicules. • Hexactinellida: Glass sponges with complex siliceous spicules.
Morphology • Typical sponge is sac-shaped with a central cavity called an osculum. • Sponges are perforated with pore openings called Ostia which filter currents.