Unformatted text preview: divided by septa (some organs are repeated in each segment); head region with sensory organs; fluid in the coelom makes a hydrostatic skeleton; closed circulatory system; ventral nerve cord; gas exchange through skin – group includes earthworms and leeches Phylum Arthropoda – Ecdysozoans with exoskeletons and jointed appendages ; segments fused into tagmata ; open circulatory system; ventral nerve cord; respiratory system with tracheae/ spiracles Class Arachnida = spiders, scorpions, ticks, and mites; body = two major tagmata Class Chilopoda ( centipedes ) and Class Diplopoda ( Millipedes ) Class Crustacea = crabs, shrimp, lobsters, crawfish, barnacles, isopods, etc. – typically have 3 tagmata, and biramous appendages Class Hexapoda = Insects – 3 body regions ( head, thorax, abdomen ) Phylum Echinodermata = deuterostomes = starfish, sea urchins, sand dollars, etc. –unique water vascular system , including tube feet used for locomotion, etc....
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- Spring '11
- #, Ventral nerve cord, Bilaterally Symmetrical animals, tagmata, secretes calcium carbonate