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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.
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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 are 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.