Sponges

Classes of Sponges  There are three different classes of sponges: –Calcarea –Silica (or glass) –Elastic

Sponge Anatomy Epidermal cells - line the outside of the sponge Pore Cells –extend through the body wall –allows water in Gelatinous Layer – The middle layer of the body wall –Contains amoeboid cells

Sponge Anatomy Amoeboid Cells –move around the sponge –secrete spicules – calcium carbonate support structures –responsible for digestion. Collar Cells –Line the internal cavity (spongocoel) –Catch food particles.

Canal Systems Allow for water flow throughout the sponge. Three different types…

Canal Systems 1.Simple Water enters spongocoel by incurrent openings of the pore cells. Cells lining the spongocoel absorb the nutrients and oxygen Left over water is expelled through the osculum.

Canal Systems 2.Advanced The body wall is folded and has more pores

Canal Systems 3.Complex Extensively branched

Calcareous sponges  Characteristics: –Usually small (4” in height). –Found in shallow waters –Skeletons made of separate spicules of calcium carbonate.

Calcareous sponges  Two different varieties: –Leucosolenia - simplest sponges that have a simple canal system. –Scypha - contain an advanced canal system.

Silica sponges  Also called Glass sponges  Characteristics: –Skeleton consists of six-pointed spicules fused in a geometric pattern. –Found in deep, tropical waters. –Possess an advanced canal system.

Elastic sponges  Largest number of sponges.  Characteristics include: –Skeleton consisting of elastic (spongin) fibers or silicon dioxide It is the elastic nature of the skeleton that makes them spongy. –They possess a complex canal system.