Deuterostomes

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Deuterostomes

• Phylum Chordata
• (Latin with a cord, notochord)
• Subphylum Urochordata ( tunicates)
• Subphylum Cephalochordata ( lancelets)
• Subphylum Vertebrata

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Phylum Chordata

• Phylum Chordata
• notochord
• dorsal nerve cord
• pharyngeal arches/clefts
• bear gills in fishes,
• modified to other structures in terrestrial
  animals
• postanal tail

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Invertebrate Chordates

• Two Subphyla of Chordata, lack distinguishing
  characters of Vertebrata
• Subphylum Urochordata
• tunicates, sea squirts
• Subphylum Cephalochordata
• lancelets, amphioxus

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Subphylum Urochordata

• Adults ( tunicates)
• Sessile filter feeders
• Ciliated pharynx
• NO notochord
• Ganglion between siphons, but NO nerve cord

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Subphylum Urochordata

• Larvae
• tadpole larva exhibits characters of Chordata
• Notochord
• Pharyngeal arches
• Dorsal nerve cord
• Post-anal tail

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Subphylum Cephalochordata

• Adults larvae
• Sessile filter feeders
• Ciliated tentacles and pharynx
• Filtered food passes into intestine
• Gas exchange through epidermis
• Pharnygeal arches are NOT gills

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Subphylum Cephalochordata
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Phylum Chordata

• Subphylum Vertebrata
• Notochord reduced, replaced by bony or
  cartilaginous vertebrae
• Some notochord tissue usually remains
• Pharyngeal arches bear gills
• or developed into other organs hyoid bone,
  larynx
• Liver
• Pancreas

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Phylum Chordata

• Subphylum Vertebrata
• 7 traditional classes
• Jawless fishes
• Cartilaginous fishes
• Bony fishes
• Amphibians
• Reptiles
• Birds
• Mammals