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Porifera https://www.youtube.com/watch?v=8gNJClc0ng4 What is a Sponge??? Metazoans Multicellular animals (3 grades) • Mesozoa - tiny worm-like parasites, few species • Parazoa - no true germ layers – Placozoa (single species!) – Porifera (the Sponges!) • Eumetazoa – true germ layers, all other phyla! Porifera = Sponges Characteristics • • • • • Multicellular, loose aggregation of cells Body of pores, canals, chambers All aquatic, most marine No organs or true tissues Sessile – does not move Unique Cells Choanocytes Flagellated cells that create current through the sponge Also used in feeding https://www.youtube.com/watch?v=8ueKlS hb9Ls Structure (skeleton) • Spongin – Fibrous protein made of collagen • Spicules – Skeleton of needle-like spikes Can be made of calcium, silica or a protein called spongin. Respiration, Circulation, Excretion • Choanocytes – Creates current of water to get oxygen – Get rid of waste from all cells • Ostium – Small intake pores, water goes IN • Osculum – Large opening, water goes OUT Nutrition/Digestion • Choanocytes - use collar to filter out small particles of food • Archeaocytes - move food around within the sponge • Pinacocytes – Absorbs nutrients Reproduction • Both Asexual and Sexual Reproduction • Choanocytes produce eggs and sperm, although not produced at same time. (monoecious) WHY???? Broken off sponge can produce more sponge Certain Choanocytes will lose their flagella and undergo meiosis Asexual Reproduction Nervous System • No real nervous system. • All instructions are at the cellular level…. nucleus Each cell only controls itself… No Brain to control all cells Water Flow in a Sponge Name the cells! Types/Body Shapes of Sponges • Asconoid • Syconoid • Lueconoid Asconoid • one simple canal from pore to central cavity or atrium called the SPONGOCOEL • Small, tube shaped sponges Syconoid • Folded wall with canals from pore to smaller canal that then goes to the larger central cavity (atrium) • Tube-shaped sponges Leuconoid • Many canals from pore to smaller incurrent canals that branch repeatedly before arriving at the larger central cavity SPONGOCOEL • Most complex of plans, biggest sponges • greatly increases food collection surfaces Food Chain • Angel fish and hawkbilled sea turtles Rock Beauty Angel Why don’t more animals eat sponges??? Symbiotic relationships Fairy Crab hiding in the crevice of a barrel sponge Brittle sea star on an Azure vase sponge Human Use of Sponges Sponge Industry Nearly brought Many sponges close to extinction Demosponges – soft, flexible, strong