Transcript Porifera
Porifera • the sponges and cousins • means " pore bearing " * bodies are full of tiny pores and canals * filter feeding depends upon water currents thru their canals * * bodies have: a gelatin matrix -- tiny spicules of Ca or Si a protein called spongin is in some • no true tissues or organs * aquatic sessile filter feeders as adults * mostly marine and colonial * many brightly colored * they provide a home for thousands of other organisms * can grow on many other living animals Form and Function • = the numerous tiny body pores ( ostia ) are for incoming water = the big pores are ( oscula ) for water exhaust = openings lined with flagellated collar cells ( choanocytes ) Function ? = these cells also phagocytize food Types of Canal Systems • >> are 3 types 1. Asconoids: flagellated spongocoels • 2. Syconoids: flagellated canals 3. Leuconoids: flagellated chambers Asconoids: • flagellated spongocoels simplest type water enters thru a spongocoel outlet is 1 large osculum Ex: Leucosolenia (means white pipe - is a littoral marine tubular species) Syconoids • flagellated canals radial canals empty into a single osculum water enters thru incurrent canals flagella force water on thru internal pores or apopyles into the spongocoel and out via the osculum this type is in classes Calcarea and Hexactinellida Ex: Sycon (means a fig) Leuconoids • flagellated chambers most common and complex clusters of flagellated chambers filled with water from incurrent canals water is discharged into excurrent canals >>> osculum form large colonies Types of Cells sponge cells are loosely arranged in a gelatinous matrix ( mesohyl , mesoglea , mesenchyme) -- Pinacocytes--thin flat epithelial-type cells Function ? -- Choanocytes--ovoid cells lining canals and chambers -- Archaeocytes--ameboid cells in the gelatin with phagocytic ability Functions ? may secrete spicules ( sclerocytes ) some secrete spongin fibers, collagen Types of Skeletons-may be of: • 1. silicon spicules 2. crystalline calcium carbonate 3. a form of collagen called spongin • variations in spicules are used as classification keys ( see text ) Physiology of Sponges • * life depends upon water flow * have millions of flagellated cells * mainly feed on bacteria, plankton and detritus Which is ?_______________________ * digestion is intracellular * diffusion and contractile vacuoles * may close oscula as a response Reproduction in Sponges • both asexual and sexual asexually by budding and fragmentation buds may be external or internal (gemmules) sexually thru being monoecious Meaning ? Sponges have great regeneration ability Class Calcarea (Calcispongiae) • = spicules of calcium carbonate = usually small sponges, often tubeshaped = all 3 canal types in this group = many drab but some bright yellow, green, red or lavender Ex: Leucosolenia (Scypha) , Sycon (Grantia) Class Hexactinellida (Hyalospongiae) • Glass Sponges > nearly all deep-sea with vase / funnel bodies > skeleton forms a network Ex: Euplectella (Venus' Flower Basket ) Class Demospongiae • * 95 % of all species * are leuconoid and almost all marine * have silicon spicules if present, are bound by spongin Ex: freshwater -Spongilla and Myenia marine - Spongia and Hippospongia Class Sclerospongiae • = small group which secretes a calcareous skeleton = called coralline ( coral like )sponges = leuconoid with silicon and spongin spicules possible = in cryptic locations SOME THOUGHTS... • Why are sponges important to other aquatic life ?_______________________ Why are sponges excellent pollution indicators ? _______________________ Do sponges still have an economic impact ? _______________________ Of what value are sponges in research ? _______________________