The Evolution of Vertebrate Diversity Chapter Ancestral chordate Brain Head Vertebral column Jaws Lungs or lung derivatives Lobed fins Legs Amniotic egg Milk Mammals Reptiles Amphibians Lobe-fins Ray-finned fishes Sharks, rays Lampreys Hagfishes Lancelets Tunicates Chordates Craniates Vertebrates Jawed vertebrates Tetrapods Amniotes Chordates Dorsal hollow nerve cord Notochord Pharyngeal slits Post-anal tail The Developmental Path 1.Craniates chrodates with a head, brain, and dorsal nerve cord 2.Vertebrates enclosure of the nerve cord and a skull enclosing the brain 3.Tetrapods jawed vertebrates with 2 paired limbed 4.Amniotes egg with shell Slime glands 1. Class Chondrichthyes includes sharks and rays skeleton of cartilage 2. Ray-finned fishes -gills skeleton of bone, swim bladder 3. Lobe-finned fishes have muscular fins supported by stout bones (could walk under water) Copyright 2009 Pearson Education, Inc Jawed vertebrates with gills and paired fins Gill openings Gills Bony skeleton Dorsal fin Anal fin Swim bladder Pelvic fin Heart Pectoral fin Operculum Rainbow trout, a ray-fin Amphibians were the first tetrapods able to move on land Most amphibians have tadpole larvae This group includes frogs, salamanders, and caecilians Found in damp habitats Respiration through skin and lungs Lay soft shelled eggs in water Toads live terrestrially First vertebrates to colonize land but near water 19.5 Amphibians Copyright 2009 Pearson Education, Inc. Reptiles (including birds) and mammals are amniotes amniotic egg with an amnion Amniotic reptiles include lizards, snakes, turtles, crocodilians, and birds Scales with keratin ectothermic, but regulate their temperature by basking or seeking shade 19.6 Reptiles Copyright 2009 Pearson Education, Inc. Birds evolved from a lineage of small, two-legged dinosaurs called theropods Adapted for flight no teeth;hollow shafts for feathers; honeycombed one structure Endothermic maintain internal body temperature Excellent vision Amniotic eggs 19.7 Birds Copyright 2009 Pearson Education, Inc. Wing claw (like dinosaur) Feathers Teeth (like dinosaur) Long tail with many vertebrae (like dinosaur) Birds have relatively large brains and display complex behaviors Copyright 2009 Pearson Education, Inc Birds endothermic hair, which insulates their bodies mammary glands, which produce milk larger relative brain size than other vertebrates a relatively long period of parental care 19.8 Mammals Copyright 2009 Pearson Education, Inc. Monotremes are egg-laying mammals Living monotremes include the duck-billed platypus Marsupials - are nurtured by a placenta within the uterus and complete development in marsupium Copyright 2009 Pearson Education, Inc Mammal Diversity Eutherians bear fully developed live young placental mammal complete entire development in amniotic sac attached to the placenta (attached to uterine wall) Copyright 2009 Pearson Education, Inc Mammals Many primate characters are arboreal adaptations Shoulder and hip joints allow climbing and brachiation Grasping hands and feet are highly mobile and flexible Sensitive hands and feet aid in manipulation A short snout and forward-pointing eyes enhance depth perception 19.9 Primates Copyright 2009 Pearson Education, Inc.