Biology

• Chordates


  Any of a phylum (Chordata) of animals having at least at some stage of development a notochord, dorsally situated central nervous system, and gill slits and including the vertebrates, lancelets, and tunicates
• Chordate


  • Hollow Nerve Cord: Nerve cord in which nerves branch out at regular intervals
  • Notochord: a long supporting rod that runs throughout body
  • Pharyngeal Pouches: Paired structures in throat
  • Muscular Tail: Extends beyond anus
• Only 4-5% of animals are chordates
• Chordates


  • Fish
  • Amphibians
  • Reptiles
  • Birds
• Cladogram


  A type of diagram that shows hypothetical relationships between groups of organisms
• Classifying items on a Cladogram

  1. Whether the animal has: Hair/Fur

  2. Jaw/Jawless

  3. Bilateral Symmetry

  4. Lungs/Gills

  5. Claws/Nails

  6. Gives birth/Lays eggs

  7. Lives in Water/On Land
• Chordates


  • Nonvertebrate chordates
  • Fishes
  • Amphibians
  • Reptiles
  • Birds
  • Mammals
  • Invertebrate ancestor
• Generalized Structure of a Chordate

  • Muscle segments
  • Tail
  • Anus
  • Pharyngeal pouches
  • Mouth
  • Hollow nerve cord
  • Notochord
• All vertebrates share common features
• Endoskeleton of Vertebrates


  • Braincase (cranium)
  • Vertebrae
  • Bones
  • Gill arches (in fish and some amphibians)
• Classes of Vertebrates


  • Agnatha (jawless fish)
  • Cartilaginous fish
  • Bony fish
  • Amphibians
  • Reptiles
  • Birds
  • Mammals
• Agnatha


  • Jawless fish
• Cartilaginous and Bony Fish

  • Presence of jaws
• Amphibians


  • Presence of four limbs
• Reptiles, Birds, and Mammals


  • Presence of an amnion
• Birds


  • Presence of feathers
• Mammals


  • Presence of hair
• Jaws


  Helped vertebrates to become successful predators
• Vertebrae


  Segmented backbone
• Four Limbs


  Let animals move from the water to life on land
• Feathers


  Insulate birds from the cold and allow for flight
• Hair


  Helps mammals to maintain constant body temperatures by providing insulation from the cold
• Tunicates may be the closest relatives to vertebrates
• The first recognizable vertebrates were jawless fish
• Jawless Fish


  • Hagfish
  • Lampreys
• Groups of Fish


  • Jawless Fish
  • Chondrichthyes (Cartilaginous Fish)
  • Osteichthyes (Bony Fish)
• Jawless Fish


  • Have mouths of soft tissue with no true teeth
  • Have no bones
  • Only vertebrates with no vertebral column as adults
• Chondrichthyes


  Skeleton built entirely of cartilage
• Osteichthyes


  • Bony Fish
  • Majority of fish fall in this order
• Fish Gills


  • Sheets of thick, frilly tissue filled with capillaries
  • Take in dissolved oxygen from water, release carbon dioxide
• Countercurrent Flow


  Opposite movement of water against the flow of blood in the fish's gills
• Fish Fins


  • Dorsal fin
  • Caudal fin
  • Anal fin
  • Pectoral fin
  • Pelvic fin
• Jaws


  Developed from gill arches located around the pharynx
• Jaws gave vertebrates a huge advantage as predators
• Jawed Fish


  • Cartilaginous fish
  • Bony fish
• Cartilaginous Fish


  Have skeletons made of cartilage
• Cartilaginous Fish


  • Holocephali (ratfish)
  • Elasmobranchs (sharks, rays, skates)
• Lateral Line System


  Sensory system sensitive to small changes in water movement
• Bony Fish


  • Have skeletons made of bone
  • Operculum protects gills
  • Movements of operculum help bony fish move water over gills
• Bony Fish


  • Ray-finned fish
  • Lobe-finned fish