Unit 9-- Vertebrates Chapter Nonvertebrate Chordates, Fishes & Amphibians Reptiles & Birds Mammals

Characteristics: At some time in their life, all chordates have: A dorsal nerve cord = gives rise to spinal cord A notochord = flexible supporting rod that gives rise to vertebrae Pharyngeal slits = gives rise to gills

Subphylum: Urochordata = Tunicate (sea squirt) only larva has all characteristics

Subphylum: Cephalochordata = Lancelets the only adult to retain all characteristics

Subphylum Vertebrata: Class Agnatha = the jawless fishes Ex: sea lampreys & hagfish

Lamprey are external parasites, 1while hagfish are “bottom feeders.”

Class Chondrichthyes Cartilaginous fishes Ex: Sharks, rays & skates

Sharks have several 6-10 rows of replaceable teeth and toothlike placoid scales

Class Osteichthyes Bony fish (with jaws & paired fins) Ex: sea horse, lion fish, perch, trout, etc

Fish anatomy: Overlapping scales for protection Gills with countercurrent exchange Operculum = gill cover Flattened bodies to increase speed

Class Amphibia “double life” Ex: frogs toads, salamanders, newts

Amphibian Anatomy Inefficient 3 chambered heart “Skin breathing” to help inefficient lungs Moist skin Webbed feet, no claws Metamorphosis

Class Reptilia Ex: snakes, lizards, turtles, alligators Tuatara = only member is its order

Reptile anatomy Ectothermic (cold- blooded) = body temp changes with environment Dry, waterproof skin with claws Partially divided 3 chambered heart

Amniote Egg allows reptiles to lay eggs on land CHORION

Rattlesnakes are “Pit vipers” with a heat sensitive organ that detects warm-blooded prey

Class Aves (the birds) Endothermic (warm-blooded) body temp constant 4 chambered heart Well-developed lungs

Bird Anatomy Feathers for insulation, protection & coloration, assist in flight Hollow bones for lightweight

Birds reduce weight for flight whenever possible, i.e. air sacs attached to lungs & one ovary in females.

Compare: Heart chambers Skin coverings Respiration types Cold vs Warm-blooded Reproduction types

Class Mammalia Hair (to insulate, camouflage, etc) Mammary glands (to nurse young) Viviparous (bear live young) Specialized teeth (determines lifestyle) Nails, claws or hooves

Classification by reproduction: Monotremes (egg-laying) Ex: platypus& echidna Marsupials (pouched) Ex: koala, kangaroo & opossum

Placental Mammals Include 95% of all Mammals Includes 15+ orders

Rodentia (gnawing) largest, most successful order largest, most successful order

Insectivores = moles… include smallest mammal, the shrew

Edentates (toothless) most primitive

Chiroptera = bats Bats are only mammals capable of “true” flight

Carnivora special traits for hunting

Aquatic mammals are capable of holding their breath for several hours Cetaceans = whales, dolphins

Hoofed mammals Are grouped by Number of toes (even or odd) They tend to be Large grazers ___dactyla

Trunk-nosed mammals have only 2 species, African and Indian Probosiceans = elephants

have opposable thumbs & superior intelligence They are the only mammal to make use of tools Primates