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Phylum Porifera Dr. Shivani Gupta, PGGCG-11, Chandigarh 1
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General Characters -Most are marine; a few live in fresh water one family Spongillidae -Metazoan, with loosely aggregated cells, therefore no organs or true tissues. -Asymmetrical or radial symmetry -Body with pores (ostia and osculum), canals, and chambers through which a water current flows. -Epidermis of flat pinacocytes; -Inner surfaces lined with flagellated collar cells (choanocytes)-create water currents
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General Characters -matrix called mesohyl contains amebocytes and skeletal elements -Skeleton of calcareous or siliceous crystalline spicules and/or protein fibers (spongin) -Digestion intracellular -Respiration and excretion by diffusion -Nervous system absent -All adults sessile and attached to substrate -Asexual reproduction by buds or gemmules -Sexual reproduction by eggs and sperm -Free-swimming ciliated amphiblastula larvae
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Simple Sponge
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Sponge Body Forms
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Syconoid Sponge Osculum Spongocoel Radial Canal Incurrent Canal
Choanocytes Incurrent Canal Ostium
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Figure 12.12a
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Syconoid Sponge Scypha (Grantia)
Spongocoel Radial Canal Choanocytes Incurrent Canal Ostium
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Leuconoid Sponge Osculum Excurrent canal
Incurrent pore Incurrent canal Choanocyte chamber
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Classification Class Subclass Calcarea (ii)Calcinea (i) Calcaronea
Hexactinellida (i)Hexasterophora (ii)Amphidiscophora Demospongia (i) Tetractinomorpha (ii)Ceractinomorpha
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Class Calcarea -All are marine, single in live in colony. -Endoskeleton is composed of spicules made of calcium carbonate. -Choanocyte cells are large. -Osculum small surrounded by spicules. Examples-Sycon,Leucosolenia, Clathrina, Petrobiona Leucosolenia Sycon Petrobiona Clathrina
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Class Hexactinellida -Flowre-vase like body.
-Spicules are composed of silica. -Choanocytes are restricted to flagellated chamber. Example: Euplectella, Hyalonema Spicule Hyalonema Euplectella 19
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Class Demospongiae -Endoskeleton may be formed by siliceous spicules or sponging fibres or both. -Choanaocytes are restricted to spherical chambers. -Spicules are having one to four rays. Examples: Cliona, Poterion, Spongilla, Helichondra Cliona Poterion Spongilla Helichondra Spongin fibres Spicules20
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Sexual Reproduction -Monoecious
Both male and female -Sperm and egg derived from choanocytes -Ciliated larva Swim to new location 21
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Asexual Reproduction -Budding -Fragmentation -Gemmule formation
survive freezing Gemmule 22
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