VERTEBRATES

VERTEBRATES

1. Cambrian era

   • Cranium, brain, paired eyes, vertebral column
     • Cartilage and bone. Duplicate Hox gene complex
     • Neural Crest

2. Key Evolutionary Steps

   • 1. HEAD: Craniates, complex movement and feeding
     • 2. VERTEBRAL COLUMN: support
       • 3. JAWS: predatory life
         • 4. BONE: replaces cartilage support
           • 5. LUNGS: Breathing air
             • 6. LEGS: move on land
               • 7. AMNIOTIC EGG: reproduce out of water
                 • 8. INSULATION: feathers/fur
                   • 9. MILK: suckling young

3. EXTANT GROUPS

   • Myxinoidea
     • Hagfish
   • Petromyzontia
     • Lampreys
   • Chondrichthes/Elasmobranchii
     • Cartilaginous fish
   • Osteichthyes
     • Bony fish
   • Amphibia
     • Frogs, toads, newts, salamanders
   • Reptilia
     • Crocodilians, snakes, dinosaurs
   • Aves
     • Birds
   • Mammalia
     • Mammals