Phylum Porifera Dr. Shivani Gupta, PGGCG-11, Chandigarh 1

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

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

Simple Sponge

Sponge Body Forms

Syconoid Sponge Osculum Spongocoel Radial Canal Incurrent Canal Choanocytes Incurrent Canal Ostium

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Figure 12.12a

Syconoid Sponge Scypha (Grantia) Spongocoel Radial Canal Choanocytes Incurrent Canal Ostium

Leuconoid Sponge Osculum Excurrent canal Incurrent pore Incurrent canal Choanocyte chamber

Classification Class Subclass Calcarea (ii)Calcinea (i) Calcaronea Hexactinellida (i)Hexasterophora (ii)Amphidiscophora Demospongia (i) Tetractinomorpha (ii)Ceractinomorpha

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

Class Hexactinellida -Flowre-vase like body. -Spicules are composed of silica. -Choanocytes are restricted to flagellated chamber. Example: Euplectella, Hyalonema Spicule Hyalonema Euplectella 19

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

Sexual Reproduction -Monoecious Both male and female -Sperm and egg derived from choanocytes -Ciliated larva Swim to new location 21

Asexual Reproduction -Budding -Fragmentation -Gemmule formation survive freezing Gemmule 22