BIOL-1116 Lecture Notes - Lecture 4: Monotreme, Amniote, Marsupial
17 Mar 2017
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Chapter 34- vertebrates: list the derived traits for: chordates, craniates, vertebrates, gnathostomes. Chordates: notochord, dorsal, hollow nerve cord, pharyngeal slits or clefts (present while you re an embryo), muscular, post anal tail (lost during development) Craniates: two or more sets of hox genes, neural crest, pharyngeal clefts that evolved into gill slits in the aquatic craniates, heart with at least two chambers. Vertebrae: vertebra enclosing a spinal cord, an elaborate skull, fin rays in the aquatic forms. Gnathostomes: have jaws, duplication of hox genes, enlarged forebrain, enhanced smell and vision, lateral line system: explain what haikouella and myllokunmingia tell us about craniate evolution. Haikouella: well formed brain, eyes and muscular segments but not a skull. Myllokunmingia: skull and true craniate: describe the trends in mineralized structures in early vertebrates. Vertebrate endoskeleton became fully mineralized much later: describe the traits of the lampreys and hagfish.
