Vertebrates

Non-Vertebrate Chordates Phylum Chordata Notochord Flexible, rod like structure that extends the length of the body Non-Vertebrate Chordates Sea Squirt Tunicate Bluebell Tunicate Brachiostoma Lancelot

SUBPHYLUM VERTEBRATA Notochord is replaced by the vertebral column

The majority of fish reproduce through external fertilization in a process called spawning. External fertilization must occur in water so the sperm can swim to the egg

FISH Jawless Fish No true teeth or jaws Skeletons made of fibers and cartilage Lack vertebrae Two classes: lamprey and hagfishes

FISH Cartilaginous Fish Skeletons built of cartilage, not bone Rays Sharks Cartilaginous Fish Skeletons built of cartilage, not bone Evolution of jaws and paired fins Tooth-like scales covering skin, make their skin very rough (sandpaper)

FISH Bony Fish Tetrapod- now extinct, four footed animal Evolved skeletons made of bone Tetrapod- now extinct, four footed animal Salmon

Costa Rica Poison Dart Frog AMPHIBIANS Life in wet places, ectothermic, smooth moist skin, lay eggs (in water) Most begin their life as aquatic organisms Ex. Frogs, toads, and salamanders Spotted Salamander Costa Rica Poison Dart Frog

Ectotherm- animals that obtain body heat from the environment

Why does reproduction still depend on water? Because eggs do not have shells to keep them from drying out.

REPTILES Fully terrestrial life (some live in water), scale covered skin, ectothermic, internal fertilization Ex. Lizards, snake, turtle Extinct- Dinosaurs

REPTILES Amniotic Egg- Covered with a protective shell Has several internal membranes with fluid Benefit: Animals do NOT have to return to the water to reproduce Evolved Advantage: Embryo surrounded by own watery environment

BIRDS Bones are lightweight, solid, and flexible allowing for flight ENDOTHERM: An organism that generates its body heat internally by its own metabolism Probably evolved from reptiles (dinosaurs) because: Eggs are also amniotic Scales on legs & feet Bones are lightweight, solid, and flexible allowing for flight

MAMMALS All mammals have hair, are endothermic, and produce milk in mammary glands

MAMMALS Monotremes - egg laying mammals Marsupials - bear young early and keep in a pouch Placentals - groups of mammals named for the organ that connects the mother with her developing embryo so that nutrients, oxygen, and wastes can be exchanged Spiny Anteater Duckbill Platypus