Vertebrates b Phylum Chordata b Subphylum Vertebrata Characteristics
Vertebrates b. Phylum: Chordata b. Subphylum: Vertebrata
Characteristics b. Notochord b. Dorsal Hollow Nerve Cord b. Pharyngeal Pouches b. Post-Anal Tail
b. Bones/Cartilage b. Cranium b. Endoskeleton
Vertebrate Evolution b 550 million years ago b. Jawless Fishes
Fishes b. Class Agnatha • Hagfishes & Lampreys
b. Cartilage Skeletons, External Fertilization, and Freshwater Fertilization.
b. Class Chondrichthyes • Sharks, Rays, and Skates
b. Placoid Scales, Lateral Line System, Olfactory Bulbs, Cartilage Skeletons, Internal Fertilization
b. Class Osteichthyes • Bony Fishes (lobe-finned and ray-finned)
b. Bone, Lungs or swim bladder, Scales, Gills, & Mostly External Fertilization.
Amphibians
Amphibian Characteristics b. Aquatic larval stage to a terrestrial adult form: metamorphosis. b. Moist, thin skin with no scales. b. Feet, if present, lack claws and often are webbed.
b. Gills, lungs, and skin used in respiration. b. Eggs lack shells. b. External Fertilization b 3 Chambered Heart
Reptiles evolved from Amphibians.
Amniotic Egg
Water-Tight Skin
Gas Exchange b. Lungs
Energy b. Ectotherms
Circulation
b. Crocodiles have a 4 chambered heart.
Birds
Feathers b. Down, Contour, & Flight
Skeleton b Lightweight and Rigid
Endothermic Metabolism b. Eat often to supply energy to maintain their warmth.
Respiratory System
Mammals
Characteristics b. Endothermy b. Hair b 4 Chambered Heart b. Milk b. Single Jawbone b. Specialized Teeth
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