Vertebrates Kingdom Animalia Phylum Chordata 6 classes: Class Osteichthyes: Bony Fish Class Chondrichthtyes: Sharks and Rays Class Amphibia: frogs, toads, salamanders Class Reptilia: lizards, snakes, turtles, crocadiles Class Aves: Birds Class Mammalia: Mammals

Class Osteichtyes: Bony Fish (salmon, trout, halibut, goldfish!) Bony skeleton Operculum (gill cover) Fish use oxygen in water Swim bladder Scales Aquatic Ectotherms Ecological roles: mutualism Sensitive to pollution: PCBs, pesticides, mercury Fish farms

Class Chondrichthyes: Sharks and Rays Skeleton made of cartilage Oil in liver (no swim bladder) Ectotherms Placoid scales Cloaca 9 of 250 shark species are man-eaters Shark cartilage used for burn victims Find prey by electrical fields Key predators in the ocean (maintain a balance) Relation to cancer, cataracts

Class Amphibia (frogs, toads, salamanders) Double life: semi-terrestrial (land and water) Young are aquatic, adults mostly on land (metamorphosis) No scales/Mucus on skin Ectotherms Frog life cycle No amniotic egg Difference between frog and toad? Declining amphibians? Frog calls Poison glands Warning coloration

Class Reptilia: snakes, lizards, turtles etc Scales Amniotic egg Terrestrial No metamorphosis Hemi-penis Jacobson’s organ (tongue flicking) Ectotherms Useful predators Venemous snakes/pit vipers Importance of alligators (keystone species)

Snake Locomotion 1. Lateral Undulation: most common form Effective in any habitat Body pressed sideways against substrate 2. Sidewinding: 2-3 points of body in contact with substrate as they pull forward sideways 3. Concertina: loops of the body used Used in burrow 4. Rectilinear: body in nearly a straight line Muscles on ribs move scutes Used by heavy snakes

Class Aves: Birds Feathers, scales on legs Terrestrial Endotherms Reptilian ancestors No urinary bladder Uropigial gland: oil gland at base of tail Uric acid Archaeopteryx (primitive bird) Many ecological roles Owl pellets illegal pet trade of exotic birds

Archaeopteryx : An Early Bird

Altricial: helpless and featherless Sparrow, eagles Lay less eggs Precocial: feathered, independent Ducks Lay more eggs

Class Mammalia: Mammals Terrestrial, although some have returned to the water Mammary glands (Milk glands) Monotremes: Primitive mammals that lay eggs (Platypus and echidna) Live birth, mouse life cycle Endotherms Types of mammals: Placentals (mouse, humans) Cetaceans (whales and dolphin) Carnivores (meat eaters such as bears, wolves) Ungulates (hooved)

A phylogeny showing the relationships among cetacean families.

Reconstruction of PakicetusPakicetus Reconstruction of Ambulocetus natansAmbulocetus Reconstruction of KutchicetusKutchicetus