Notes on Porifera | Grade 11 > Biology > Introduction to kingdom Animalia | KULLABS.COM

Porifera

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Example of phylum Porifera
source:www.kullabs.com
fig:Example of phylum Porifera

Porifera (Gr.Porous-Pores, ferry- bearing)

  • Porifera includes plant-like creatures with a large number of minute pores. So, commonly called sponges.
  • John Ellis first recognised the sponges as an animal.
  • Robert Grant coined the term "Porifera".
  • The study of sponges or poriferans is called parazoology.

General Characteristic feature of phylum Porifera:

  • All of them are aquatic, mostly marine, rarely freshwater, solitary or colonial, sessile or redentary.
  • Body shape is vase shaped, cylindrical, spherical, cup or disc-shaped. Asymmetrical or radially symmetrical.
  • The cellular level of body organisation.
  • Diploblastic.
  • The adult body wall consists of two layers i.e. outer pinacoderm made up of a flattened cell or inner gastral choanoderm made up of complex flagellated collar cells. In between two layers, there is non-cellular mesogloea.
  • In mesogloea, there is supporting endoskeleton called spicules which are made up of CaCO3(Calcareous), SiO3(Siliceous) or protein (SpoenginRibres).
  • There is peculiar canal system whose central cavity is called paragestral cavity or sponge cell. Canal system gets in food and oxygen and carries out carbon dioxide and wastes.
  • The body surface is perforated with a large number of minute inhalant pores called Ostia and one largest exhalent pore called osculum.
  • Nutrition is holozoic and digestion is intracellular.
  • Circulation absent, respiration, and excretion through diffusion.
  • Nervous system and sense organs completely absent.
  • Bisexual reproduction asexually and sexually fusion of gametes.
  • Fertilization is internal.
  • Develop is indirect.

Classification:

Porifera consists of almost 5000 living species. They are divided into three classes on the basis of types if spicules.

Leucosolenea
source:www.easterncapescubadiving.co.za
fig:Leucosolenea
Calcarea or calerspongia:
  • They are marine, solitary or colonial.
  • Mononon, Trianon and tetra non-type of spicules made up of CaC03.
  • Radially symmetrical.
  • A Simple canal system.
  • Eg; Sycon, Leucosolenea.
Euplectella
source:cornerofthecabinet.com
fig:Euplectella
Hyatospongiea or henantinillida:
  • They are marine found in deep sea and ocean.
  • Trianon spicules made up of Si03.
  • Radially symmetrical.
  • Branch or unbranch canal system.
  • Eg; Hyalenema, Euplectella.
Cliona
source:biogeodb.stri.si.edu
fig:Cliona
Demospongiea:
  • They are marine except spongilla. Spongilla is freshwater form.
  • Mono and Tetracon spicules made up of spongin fibre.
  • Asymmetrical
  • Complex alimentary canal.
  • Eg; Spongilla, Cliona.



  • Porifera includes plant like creatures with large number of minute pores. So, commonly called sponges.
  • The study of sponges or poriferans is called parazoology.
  • All of them are aquatic, mostly marine, rarely fresh water, solitary or colonial, sessile or redentary.
  • Porifera consists of almost 5000 living species.They are divided into three classes on the basis of types if spicules.
  • Body shape is vase shaped, cylindrical, spherical, cup or disc-shaped.Asymmetrical or radially symmetrical.
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