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Echinoderms and Invertebrate Chordates

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Sea Cucumber

Brittle Star



Phylum Echinodermata;
   -sea urchins, sea stars, sea cucumber, brittle stars, sand dollars, sea lillies
   -entirely marine
   -endoskeleton, series of plates underneath the skin
   -have a water vascular system which helps them move around in the water
   -have gills
   -reproduce sexually or asexually
   -sea stars are carnviorous, their stomach folds out to digest the food then folds back in.
   -sea cucumbers and brittle stars eat small organisms
   -sea urchins are herbivorous
  Their nervous system has a central nervous ring with nerves that go down each arm. There are touch receptors and eyespots on each arm. They have radial symmetry but the larvi are bilateral. The exception are sea cumcumbers which have bilateral symmetry even as an adult.

Invertebrate Chordates
 Phylum Chordata;
   They have
   -notocord, flexible rod-like structure that is made out of mesoderm
   -dorsal hollow nerve cord, from the ectoderm
   -gills (pheryngial gills)
   -post anal tail
   -blocks of muscle
Subphylum Urochordata
   -2 stages: larvel have all five factors, adults only have the gills

Subphylum Cephalochordata
   -lancelets, small organism
   -filter feeders
   -embed themselves in mud and collects particles from the water

mollusks and annelids


Subphylum Vertabrata

reptiles and birds