01:119:116 Lecture Notes - Lecture 6: Gastrovascular Cavity, Lophophore, Radula
22 Apr 2016
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Document Summary
Account for >95% of known animal species. Found in almost every habitat on earth. Phylum porifera ( to have pores = sponges) Multicellular specialised cells, but no true tissues or organs. Asymmetric two halves of body are not similar to one another. Spongocoel: central cavity acts as a passage for water. Sponges act as filter feeders filter out food particles. Hollow sac with mouth and tentacles at one end. Mouth: only opening in the body ingest food and expel wastes. Gastrovascular cavity: digestive compartment with single opening. Cnidocytes: specialised cells in tentacles function in defense/prey capture. Lophophore: crown of ciliated tentacles around mouth feeding structure. Alimentary canal complete digestive tract (tube with two openings) Crown of cilia at head draws vortex of water into the mouth. Trophi jaws that grind up food (microorganisms suspended in water) Soft body most covered by dorsal shell of calcium carbonate. Has a radula belt of teeth in mouth area.
