PHYLUM CHORDATA

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PHYLUM CHORDATA
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PHYLUM CHORDATA

• Notochord
• Hollow nerve cord
• Pharyngeal slits
• 47 000 species

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THREE SUBPHYLUMS

• SUBPHYLUM
• smaller than a phylum
• larger than a class
• SUPERCLASS
• larger than a class
• smaller than a phylum

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CHORDATA SUBPHYLUMS

• SUBPHYLUM UROCHORDATA
• Marine Tunicates
• 2 000 species
• SUBPHYLUM CEPHALOCHORDATA
• Lancelets 25 species
• SUBPHYLUM VERTEBRATA

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SUBPHYLUM VERTEBRATA

• Possess vertebrae p. 779-780
• Repeating bony unit of backbone
• 9 classes
• from 8 classes that were 7 classes
• Superclass Agnatha

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(Super)class Agnatha

• JAWLESS FISH
• Class Myxini
• hagfish
  p. 783
• mouth surrounded by tentacles
• Class Cephalaspidomorphi
• lamprey rasping tongue p.784

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CLASS CHONDRICHTHYES

• -ichthyes fish
• CARTILAGIOUS FISH
• Placoid scales p.784
  teethlike plates embedded in skin
• ovoviviparous
• Young nourished by yolk sac in females body
• Sharks / Rays / Skates

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Recent Change

• 9 classes
• from 8 classes that were 7 classes
• Former CLASS OSTEICHTHYES
• divided into Class Actinopterygii
• ray-finned fish
• Class Sarcopterygii
• lobed finned fish -- lungfish / coelacanth

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CLASS OSTEICHTHYES

• Oste -- bone
• Bony fish
• Most numerous aquatic vertebral group
• MOIST (mucus) scales
• Oviparous lays eggs outside body
• Exothermic
• temperature dependent upon environment

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CLASS AMPHIBIA

• Moist skin
• Must return to the water to reproduce
• oviparous
• Developmental metamorphosis
• change in body form
• exothermic

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CLASS REPTILIA

• May be totally terrestrial
• Dry scales
• Oviparous
• Amniotic egg
• prevents desiccation drying out
• exothermic

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LINK from LAND to AIR

• ARCHAEOPTERYX p. 843
• Flying reptile
• Winged fossil that shows evidence of
  
  feathers
• 
  

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CLASS AVES

• Feathers
• Hollow bones
• Oviparous
• Endothermic 40-41oC (104-106oF)
• Maintains
  homeostasis
• Beaks
• Wings

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CLASS MAMMALIA

• Viviparous bear young live
• young nourished from mothers body
• Endothermic
• Hair / fur
• Nurse young --- mammary glands
• p. 868