BIOL 2003 Lecture Notes - Lecture 15: Tube Feet, Detritivore, Filter Feeder
8 Jan 2018
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Phylum echinodermata ( spiny skin ): more closely related to humans to any group discussed before, exclusively marine, mostly benthic, 7000+ species in 5 classes lack cephalization secondarily lost. Made of ossicles (calcareous plates) = connected by collagen. Loosely connected not really a true skeleton. Catch collagen = liquid to solid state very fast extend lots of force without much effort. Part of a unique coelom called the stereom filled with ossicles. Podia tube feet (little feet under their arms for locomotion) Functions; respiration, excretion, locomotion, feeding (originally, in ancestors still now) Water can come in (through siv plate and it goes throughout the body) If you were to puncture one of their tube feet, it would basically make is useless. Cause the water would escape the tube feet. Main reason why they are only marine. Some are specialized with nerves at end of tube feet for tasting water and such.
