PHYLUM CHORDATA
 Characteristics
 Notochord (firm, flexible rod)

Replaced by backbone in some
 Hollow dorsal nerve cord (hollow tube above the notochord)

Develops into brain and spinal cord in some
 Pharyngeal slits
SUBPHYLUM VERTEBRATA
 Vertebrates have:
 Vertebrae (backbone)
 Cranium
 Endoskeleton
VERTEBRATE CHARACTERISTICS AND
TRENDS
 water  land
 gelatinous egg laying 
amniotic eggs
 no scales  feathers or hair
 internal skeleton
 2-chambered heart  4chambered heart
 un-paired fins  legs (wings)
JAWLESS FISHES
Class Agnathostomata
 Notochord remains throughout life
 Un-paired fins
 Gelatinous eggs
CARTILAGINOUS FISHES
Class Chondrichthyes
 Cartilage skeleton, jaws, paired fins
 Gelatinous eggs, gills absorb O2 from water
BONY FISHES
Class Osteichthyes
 All bones, gills, scales
 2 chambered heart
 gelatinous eggs, ectothermic (cold-blooded)
AMPHIBIANS
Class Amphibia
 3-chambered heart, breathe through lungs and skin
 Skin is moist and permeable
AMPHIBIANS
Class Amphibia
 3-chambered heart, breathe through lungs and skin
 Skin is moist and permeable
 lay gelatinous eggs in water, ectothermic
 Spends part of life in water
 Appendages: arms, legs, and sometime tails
REPTILES
Class Reptilia
 3-chambered heart in most
 Scales, Breathes air, Ectothermic
REPTILES
Class Reptilia
 3-chambered heart in most
 Scales, Breathes air, Ectothermic
 Amniotic egg: 4 layers and a self-contained aquatic
environment
 Appendages: arms, legs, and tails
BIRDS
Class Aves
 Regulators/endothermic, amniotic eggs,
 4- chambered heart, lungs
BIRDS
Class Aves
 Regulators/endothermic, amniotic eggs,
 4- chambered heart, lungs
 feathers, wings
 Lightweight skeleton
MAMMALS
Class Mammalia
 Hair/fur, mammary glands, specialized teeth
 lungs, 4-chambered heart
MAMMALS
Class Mammalia
 Hair/fur, mammary glands, specialized teeth
 lungs, 4-chambered heart
 placenta(development inside parent for most)
 Regulators/endothermic
Mammals