Phylum Chordata

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Phylum Chordata

• 4 common characteristics
• Notochorddorsal rod made of cartilage
  (flexible/firm), support for body
• dorsal nerve chordgroup of nerves forming a
  hollow tube above notochord (becomes spinal cord)
• pharyngeal slitsperforations in the throat (some
  form gills, lungs, head, etc)
• a postanal tail that extends past the anus
• All chordates have all four of these
  characteristics at some time in their life, even
  if it is only briefly as embryos

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Typical Chordate Representation
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Chordates continued

• There are three subphyla of Phylum Chordata
• There are two subphylas of invertebrate
  chordates Tunicates and Lancelets
• One large subphylum Vertebrata

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Tunicates
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Lancelets
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Sub Phyla- Vertebrata

• Dorsal Nerve Cord
• Vertebrates
• Regionalized Brain
• Bilateral
• Systems Interact
• Classes
• Agnatha -- Chondrichthyes -- Osteichthyes
• Amphibia -- Reptilia -- Aves -- Mammalia

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Subphylum Vertebrata (Vertebrates)

• 44,000 species, found on land, fresh and marine
  water
• Segmented vertebral column (backbone) replaces
  notochord, surrounds/protects nerve chord
• Endoskeleton made up of living cells and tissues
  (allows growth, large size), jaws (efficient way
  of eating)
• Distinct head and brain inside skull, gill slits
  remain or are modified during development
• Interaction of muscular, skeletal, and nervous
  system leads to greater speed and agility

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Fishes have

• Endoskeletons
• cartilage or bone
• Breathe with gills
• Closed-loop circulation
• Kidneys
• Aquatic
• Cold blooded (ectotherms)
• 3 main existing classes

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Jawless Fish

• First vertebrates
• No scales
• Retain notochord
• Lamprey, hagfish
• Cartilage endoskeleton

 
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Cartilaginous Fish

• Cartilaginous fish
• No swim bladder
• Tooth-like scales
• Internal fertilization with live birth

Sharks, rays, skates
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Bony Fish

• Bony endoskeleton
• Scales
• Lateral line system
• Swim Bladder
• Opercula

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Tetrapods

• Presence of 4 appendages
• Ancestor may have been the lobe-finned fish

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Amphibians

• First to live on land
• Cutaneous Respiration
• Life in water/on land
• Lungs
• Water for reproduction

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Frog Life Cycle
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Reptiles

• Dry skin, scales
• Internal fertilization
• Amniotic egg
• Lungs
• Ectothermic

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Birds

• Endothermic
• 4 chambered heart
• Feathersmodified scales
• Light, hollow bones for flight

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Mammals

• Mammary glands
• Endothermic
• Specialized teeth
• Internal Feritlization
• Hair

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3 Mammalian Orders

• 1) Marsupials- young born at immature stage and
  complete development in pouch
• 2) Monotremes- egg-laying, oviparous
• 3) Placentals- develop completely inside uterus,
  nourished by the placenta
• 95 of mammal species are placental

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Class Mammalia