Ch. 34

Characteristics Notochord Dorsal, hollow nerve cord Muscular post-anal tail Gill slits

Gills

Simple Chordates Urochordata – tunicates Cephalochordata – lancelets

Challenges Faced Chasing food Grabbing food when close Getting oxygen from environment Getting oxygen through body Preventing dehydration Maintaining body temperature Keeping embryos from drying out

Fish Agnathans

Fish Evolution of jaws

Fish - Chondrichthyes Lateral line

Fish - Osteichthyes Operculum Swim bladder

Class Amphibia

Gills as juvenile Lousy lungs Moist skin

Class Amphibia Improved circulation

Class Reptilia

Paraphyletic

Class Reptilia Dry skin Amniotic eggs Internal fertilization

Class Reptilia Branching in lungs

Class Reptilia Partial septum in heart

Class Aves

Lightweight, hollow bones Large breastbone

Class Aves Feathers

Class Aves Endothermy

Class Aves Four-chambered heart

Class Aves Best lungs – one-way respiration

Class Aves

Class Mammalia

Mammary glands Hair Specialized teeth

Class Mammalia Monotremes

Class Mammalia Marsupials

Class Mammalia Eutherians