Phylum Chordata, Subphylum Vertebrata, Superclass Gnathostomata, Class Reptilia, Subclass Diapsida Order Testudines Superorder Lepidosauria Order Sphenodonta Phylum Chordata, Subphylum Vertebrata, Superclass Gnathostomata, Class Reptilia, Subclass Diapsida Clade Archosauria ruling lizard Crocodile Heart Bird Heart Phylum Chordata, Subphylum Vertebrata, Superclass Gnathostomata, Class Reptilia, Subclass Diapsida Superorder Archosauria Order Crocodilia Phylum Chordata, Subphylum Vertebrata, Superclass Gnathostomata, Class Aves, Subclass Neornithes Craniata (euchordates with a cranium) = Vertebrata Gnathostomata (Craniata with jaws) Osteichthyes (bony fishes + tetrapods) Tetrapoda (four-limbed vertebrates) Amniota (tetrapods with embryos having extraembryonic membranes) Reptilia ProtochordataAgnatha Urochordata (tunicates) Cephalaspidomorphi (lampreys) Actinopterygii (ray-finned fishes) Actinistia Amphibia Mammalia (mammals) Lepidosauria (lizards, snakes) Testudines (turtles) Crocodilia Aves (birds) Cephalochordata (lancelets) Myxini (hagfishes) Chondrichthyes (sharks, rays, chimaeras) Slime glands, accessory hearts Suckerlike oral disc, long larval stage, 7 pairs of gills Heterocercal caudal fin, placoid scales, cartilaginous skeleton Hair, mammary glands Notochord, dorsal hollow nerve cord, pharyngeal slits, postanal tail, endostyle Neural crest Distinct head and tripartite brain, skull, paired specialized sense organs, vertebrae Jaws, pelvic and pectoral girdles, calcified teeth, gill filaments lateral to gill support Lung or swimbladder derived from gut, bony endoskeleton Paired appendages with long muscular lobes, unique supportive elements in skeleton or girdles of appendages, pulmonary vein Four pentadactylous limbs, stapes, atlas (1 st cervical vertebra) Egg with extraembryonic membranes, keratinized skin, axis (2 nd cervical vertebra), aspiration pump Skull with upper and lower temporal fenestra, Beta-keratin in epidermis Dipnoi Sarcopterygii (lobe-finned) Pulmonary circulation, two chambered atrium Chordata (animals with notochord at some stage in life cycle) Class Mammalia Phylum Chordata, Subphylum Vertebrata, Superclass Gnathostomata, Class Mammalia Rommel and Reynolds, 2000 Marine Mammals Cetaceans Pinnipeds Sirenians Polar bear Sea otter Order Artiodactyla Suborder Cetacea Order Carnivora Suborder Pinnipedia Order Sirenia Family Ursidae Family Mustelidae Whats the big deal about being an aquatic mammal? Problem and Solutions Problem: Heat conductivity of water 25x that of air Solutions? Solutions Insulation Marine mammals - two forms of insulation FurBlubber INSULATION THICKNESS (mm) INSULATION (W -1 M 2o C) Still AirDry Fur Wood Adipose Muscle Water Copper Sea otter hair, Wet Harbor porpoise blubber Spotted dolphin blubber INSULATION THICKNESS (mm) INSULATION (W -1 M 2o C Still AirDry Fur Wood Adipose Muscle Water Copper Polar bear hair, Dry Polar bear hair, Wet Thermal Windows Feet Flippers Dorsal fin Pectoral flippers Tailflukes Rommel et al., 98 Countercurrent exchanger Conclusions Marine mammal solutions Insulation - fur and blubber Vasculature Thermal Problem for Male Reproductive Systems Problem: Sperm production requires lower temp Terrestrial mammal solution Scrotum or cremaster sacs Rommel et al., 98 The Cetacean Solution Rommel et al., 92 Rommel et al., 98 Structure without function is a corpse; function sans structure is a ghost - Vogel and Wainwright, 69