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2014-03-31 12:50:04
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  1. Phylum Echinodermata (star fish, sea urchins etc)
    • Calcerous endoskeleton
    • preserved well in fossils
  2. Echinodermata basic characteristics
    • slow, sessile and marine
    • pentaradial symmetry (5) in adults
    • bilateral symmetry in larvae 
    • thin epidermis covers endoskeleton
    • no central brain
  3. function of madreporite
    allows water to flow in and out of system (Echinodermata)
  4. Function of tube feet in Echinodermata
    • locomotion, feeding and gas exchange 
    • operated by water pressure and adhesion
  5. Echinodermata reproduction
    • usually separate sexes
    • engage in broadcast spawning (fertilization occurs in open water)
  6. Echinodermata- Class Echinoidea
    • sea urchins and sand dollars
    • no arms
    • rows of tube feet
    • slow
    • spines are used for locomotion and protection
    • eat seaweed
  7. Echinodermata-Class Holothuroidea
    • sea cucumbers
    • elongated
    • secondary bilateral
    • 5 rows of tube feet
    • tube feet around mouth serve as feeding tentacles
    • deposit or suspension feeders
    • shoot out internal organs when disturbed
  8. Phylum Chordata
    • 4 synapomorphies (shared derived characteristics)
    • have a notochord
  9. What is a notochord? (chordates)
    • flexible rod located dorsally, between digestive tube and nerve cord
    • stiff but not rigid
    • always present in embryos, not always in adults
    • in many vertebrates it is reduced to a bad between vertebrae
  10. What are the four synapomorphies in chordates?
    • 1. Notochord
    • 2. Dorsal hollow nerve cord
    • 3. Pharyngeal slits/clefts
    • 4. Muscular post-anal tail
  11. Dorsal, hollow nerve cord development
    • unique to chordates (solid in other animals)
    • develops from plate of ectoderm dorsal to notochord
    • plate rolls into tube during embryonic development
    • anterior portion develops into brain
  12. Pharyngeal slits/clefts functions
    • connects pharynx to external environment
    • allows water that enters mouth to exit before entering digestive system 
    • used for suspension feeding
    • gas exchange, jaw supports and hearing
  13. Muscular post-anal tail
    contains muscle and skeletal elements