l. Chordata subphyla: Urochordata Cephalochordata Vertebrata

Patterns in evolution: Innovation, radiation, competitive contraction

5. Major Phyla Deuterostomes: l. Chordata Vertebrata “Jawless fishes” Lampreys and Hagfish Lamprey larvae look very much like cephalochordates

5. Major Phyla Deuterostomes: I. Chordata Vertebrata “Jawless fishes” Evolve in late Cambrian, radiate in the Ordovician

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes – Jawed Vertebrates Move from detritivores to predators

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes – Jawed Vertebrates The Devonian was the “Age of Fishes” – a radiation of the first jawed vertebrates, dominated first by the Placoderms and then by Cartilaginous and bony fishes Arthrodires Placoderms Antiarchs Chondrichthyes (Sharks, rays) Acanthodians Teleosts Ray-finned Fishes Bony Fish Lobe-finned Fishes

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes – Jawed Vertebrates The Devonian was the “Age of Fishes” – a radiation of the first jawed vertebrates, dominated first by the Placoderms and then by cartilaginous and bony fishes

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes – Jawed Vertebrates Bony fishes dominate today: lighter skeleton and swim bladder Ray-finned Fishes Lobe-finned Fishes

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes – Jawed Vertebrates Bony Fishes (Osteichthyes) comprise 40% of living vertebrate species

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes - Tetrapods 350 mya Devonian 417 mya

Radiation of the “stem tetrapods” !!! Carboniferous Coastal swamps! Old friends a fish

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes - Tetrapods Caecilians Salamanders Frogs

Radiation of the “stem tetrapods” !!! Carboniferous Coastal swamps! Old friends a fish

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes The Permian Formation of Pangaea dries the landscape; amniotes dominate like the gymnosperms.

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes The amniotic egg was a big advance - amnion protects the embryo - yolk sac provides nourishment - allantoic sac holds waste produced by embryo Resist desiccation Provision embryo allows for colonization of dry habitats

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Amniote ancestor Hylonomus Casineria ANAPSID (turtles?) DIAPSID SYNAPSID

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Dimetrodon – a Pelycosaur The Permian The synapsids radiate and dominate Mammals Cynodonts Gorgonopsids Therapsids Pelycosaurs Dicynodonts A cynodont

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Mammals - excellent transitional sequences from cynodont ‘reptiles’ - first fossils with all mammalian features (jaw, ear, dentition, fur) date to ~200 mya - Morganucodontids

Radiations of Mammals They diversify during the Mesozoic, but the modern groups radiate and dominate in the Cenozoic

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Mammals - Monotremes: lay eggs, “sweat” milk

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Mammals - Marsupials: live birth to embryo – attaches to nipple to complete development. Mother does not need to abandon the nest/young to feed. Pygmy possum – Australia (opossums in Western Hemisphere)

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Mammals - Monotremes: egg laying, “sweat” milk - Marsupials: live birth to embryo – attaches to nipple to complete development. Mother does not need to abandon the nest/young to feed. - Placentals: Longer internal development allows for precocial behavior (independence on birth); placental allows for direct, energy-efficient transfer of nutrients between blood systems of mother and offspring. FOOD DIGESTION Nutrients in bloodstream of mother Milk production in mammary glands FOOD for OFFSPRING Nutrients in bloodstream of offspring Placenta Each energy transformation is less than 100% efficient

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes - Archosaurs Crocodilians Pterosaurs Ornithiscians Dinosaurs Sauropods Theropods Carnosaurs Saurischians Birds

Feathers: - ornamentation - endothermy (insulation) - lift (flight)

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes Birds: (derived traits) No teeth Feathers and endothermy flight feathers keeled breastbone Clavicles united into wishbone Pneumatic skeleton (houses air sacs from respiratory system) Unidirectional respiration

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes In the Mesozoic, the synapsids are replaced by the great diapsid radiations of Ichthyosaurs, Pterosaurs, and Dinosaurs Diapsida Younginiformes Ichthyosaurs Lepidosaurs: Lizards, Snakes, Sphenodonts) Archosaurs: Dinosaurs, Pterosaurs, Crocodilians, Birds

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes - Lepidosaurs Keuhniosaurs Squamates Scales, moveable quadrate (double hinged jaw), hinged skull Rhynchocephalians (Tuatara)

5. Major Phyla Deuterostomes: l. Chordata Vertebrata Gnathostomes Tetrapods - Amniotes - Lepidosaurs - Squamates