Introduction to Sponges

Porifera – “Pore-bearing” – Over 4,000 species – Mostly marine

Classification Kingdom Animalia – Plant-like in appearance – Lack some typical animal characteristics Distinct tissues Dead end phylum – Nothing evolved from the Porifera

Classification Organized into three classes – Based on skeleton structure differences Calcareous sponges Glass sponges Encrusting sponges

Calcareous Sponges Classification – Class Calcarea Size – Small, 4 inches or smaller Location – Shallow waters

Calcareous Sponges Structure – Skeletons made of spicules “little spikes” Made of calcium carbonate (lime)

Calcareous Sponges Two types – Leucosolenia Simple (asconoid) canal system

– Scypha Advanced (syconoid) canal system

Canal System Function Simple canal system – Water enters internal cavity (spongoceol) through pore cells in the body wall Pore cell openings – incurrent openings (ostia) Cells of the spongoceol absorb nutrients and oxygen – Water exits through excurrent opening (osculum)

Advanced canal system – Folded body walls Increases surface area – Greater absorption of nutrients and oxygen

Glass Sponges Classification – Class Hexactinellida Size – Larger, vase-shaped Location – Deep, tropical waters

Structure – Skeleton made of crystalline silicon dioxide Geometric pattern Formed by six-pointed spicules Possesses advanced canal system

Encrusting Sponges Classification – Demospongiae (Demo – “people”) Used as bath sponges Size – Large Location – Gulf of Mexico, Caribbean, Mediterranean Sea

Encrusting Sponges Structure – Skeleton can be made of: Elastic (spongin) fibers – Makes them “spongy” Silicon dioxide Combination of both

– Possess a complex (leuconoid) canal system Commercial use – Collected by divers Allowed to die/decompose in water – Spongy skeleton remains and is cleaned to be sold