classes of sponges and sponge anatomy notes HW

classes of sponges and sponge anatomy notes HW:

Classes of Sponges ¬There are three different classes of sponges: – Calcarea – Hexactinellida (Glass Sponges) – Demospongia

Canal Systems ¬ Canal systems refer to method of water flow throughout the sponge. ¬ There are three different types of canal system: – Simple (asconoid) • Water enters spongocoel by incurrent openings of the pore cells. Cells lining the spongocoel absorb the nutrients and oxygen and left over water is expelled through the osculum. – Advanced (Syconoid) • The body wall is folded, accomodating more pores without increasing the size of the sponge. – Complex (Leuconoid) • This canal system is extensively branched, and thus more complex.

Calcarerous Sponges ¬Sponges of the class Calcaera are known as calcareous sponges. ¬Their specific characteristics include: – are usually small (4” in height). – Found in shallow waters – Skeletons are made up of separate spicules of calcium carbonate.

Calcaerous Sponges ¬There are two different varieties: – Leucosolenia • These are the simplest sponges that have a simple canal system. – Scypha • These contain an advanced canal system. – There also calcareous sponges that have a complex canal system.

Class Hexactinellida ¬This class is commonly known as glass sponges. ¬Their specific characteristics include: – Skeleton consists of six-pointed spicules fused in a geometric pattern. – Found in deep, tropical waters. – Possess an advanced canal system.

Class Demospongia ¬This class contains that largest number of sponges. ¬They are also the most marketable sponges, often used as cleaning products. ¬Their specific characteristics include: – Skeleton consisting of elastic (spongin) fibers, silicon dioxide, or a combination of the two. • It is the elastic nature of the skeleton that makes them spongy. – They possess a complex canal system.

Sponge Anatomy ¬ Sponges have the following types of cells: – Epidermal cells – line the outside of the sponge. – Pore Cells – Which extend through the body wall of the sponge to allow water in. – Gelatinous Layer – The middle layer of the body wall that is jelly-like and contains mobile amoeboid cells. – Amoeboid Cells – mobile cells that move around the sponge, secrete spicules, and are responsible for digestion. • Spicules – are the calcium carbonate structures that are imbedded in the body wall of the sponge to support it. – Collar Cells – Line the internal cavity (spongocoel), and have flagella used to catch food particles.