Chem

• Cnidaria


  Derived from Greek word 'knide' (nettle) and Latin word 'Aria' (Connected with)
• Characteristics of Cnidaria


  • Organized in cellular and tissue level
  • Visibly headless
  • Diploblastic
  • Cnidocyte cells with nematocyst
  • Digestion via Coelenteron
  • Sessile polyp or free swimming medusa
  • Polymorphism
  • Unisexual or bisexual
  • Ciliated Plannula larva
• Animals of the phylum Cnidaria are
• Most of them are marine and some are fresh water animals
• Mesoglea


  Acellular material present between epidermis and endodermis in Cnidaria
• Mesoglea is present in the animals of the phylum Cnidaria
• Hydra


  An animal with two embryonic layers
• Hydra


  An animal with radial symmetry
• Platyhelminthes


  Derived from Greek words 'Plat' (Flat) and 'helminthes' (worm)
• Characteristics of Platyhelminthes


  • Bilaterally symmetrical
  • Triploblastic
• Porous


  Pore
• Ferre


  Carrier
• Characteristics of Porifera


  • They are the simplest multicellular organisms
  • Cells are not arranged in tissues
  • They show cellular level of organization
  • Numerous pores named ostium are present on their body surface
  • Ostia are connected with canals and chambers internally forming a canal system
  • Internal transportation is done by this canal system
  • Endoskeleton composed of spicules or spongin made of collagen protein or both
  • Body consists of flagellated cells named "Choanocytes"
  • Wide body cavity named spongocoel opens outside by the marginal pore called osculum
  • They are bisexual animals, reproduce by both sexual and asexual methods
  • They are mobile in larval stage and sessile in mature stage
  • Matured ones remain attached to any substratum
  • Development is indirect
• Free swimming amphiblastula or Parenchymula larval stage is present in Porifera
• An animal of the Phylum Porifera is Scypha
• Spongocoel is found in the phylum Porifera