Lecture 8: Introduction to Vertebrates.

• Chordates: notochord
• what is the notochord: stiff cartilaginous rod that extends along the inside body.
• chordates possess: notochord, dorsal hollow nerve cord, postanal tail.
• Non-Vertebrate Chordates: small marine animals.
• subphylum urochordata: most adults lack many chordate features.
• subphylum urochordata: tadpole-like free-swimming larvae more typical.
• subphylum cephalochordate: larval form has chordatal features but adults retain pharyngeal slits for filter feeding.
• subphylum cephalochordate: adults fish-like, retain free-swimming of larvae but often inactive.
• vertebrate defining features: SPINE, CRANIUM, SPINAL CORD.
• Jawless fish (agnatha): lack jaws and lack paired fins.
• Jawless fish (agnatha): elongate, scaleless and slimy.
• Jawless fish (agnatha): Hagfish: no vertebral column, marine scavengers.
• Cartilaginous fish (Chondrichthyes): cartiligenous skeletons and paired fins.
• Cartilaginous fish (Chondrichthyes): sharks and rays have multiple gill openings, mostly marine filter feeders.
• Bony fish (Osteichthyes): bony skeletons, paired fins, swim bladders.
• Bony fish (Osteichthyes): ray-finned- find are webs supported by spines, incredibly diverse.
• Bony fish (Osteichthyes): lobe finned- fleshy, lobe finned attached by 1 bone.
• Amphibians (amphibia): tetrapods with mosit, scaleless skin for gas exchange.
• Amphibians (amphibia): many with aquatic larvae and terrestrial adults.
• Amphibians (amphibia): metamorphosis
• Amphibians (amphibia): all canivores as adults.
• Amphibians (amphibia): frogs and toads- short body, big head, large hind legs for jumping.
• Amphibians (amphibia): frogs and toads most divers group.
• Amphibians (amphibia): salamanders- elongated body, mostly terrestrial as adults.
• Reptiles (reptilia): tetrapods with scaly skin.
• Reptiles (reptilia): turltes have bony cartilgenous shell,
• Reptiles (reptilia): lizards and snakes- horny sclaed skin, movable quadrates, most diverse group.
• Reptiles (reptilia): crocodilia- largr and lizard like, flattened snout with ears, eayes and nostirls on top, aquatic lifestlyle.
• current conservation efforts will not prevent another mass extinction.