BIOL108 Lecture Notes - Lecture 27: Agnatha, Craniate, Vertebral Column

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Biol 108 - lecture #27 - craniates, vertebrates, gnathostomes. Chordates with a head: cranium = skull. Allows for more coordinate movement and complex feeding behaviour. Includes the largest animals that ever lived: eg. sauropods, blue whales, most are vertebrates. Craniate derived character state: 2 or more clusters of hox genes, neural crest, endoskeleton and pronounced cephalization, circulatory system modified, pharyngeal clefts. Jawless craniates: 2 classes of craniates don"t have jaws. The mouth is like a opening to a tube. Long, flexible tubular bodies, that have no paired fins: class myxini. Feed on soft-bodied worms or on corpses of larger animals. Grip flesh using the keratinous plates in the mouth. Slide knot forwards until braced against flesh. Protect themselves by exuding slime (myxo = slime) A chain of skeletal elements surrounding and protecting the nerve chord. More complex nervous system: replaces function of notochord. Provide attachment sites for muscle and other skeletal elements (eg. ribs: class petromyzontida.