Phylum Chordata The chordates

Five Chordate Hallmarks  Notochord – flexible rodlike structure; extending length of body

Five Chordate Hallmarks  Dorsal tubular nerve cord

Five Chordate Hallmarks  Pharyngeal pouches and gill slits

Five Chordate Hallmarks  Endostyle or thyroid gland – secretes mucous that traps food particles in pharyngeal cavity

Five Chordate Hallmarks  Postanal tail – tail extends beyond anus

Sixth Chordate Feature  Ventral Heart – heart located ventrally

Higher Classification of Chordata  Phylum Chordata Subphylum Urochordata – tunicates, sea squirts Subphylum Urochordata – tunicates, sea squirts SubphylumCephalachordata – lancelets SubphylumCephalachordata – lancelets Subphlum Vertebrata- vertebrates Subphlum Vertebrata- vertebrates

Subphylum Urochordata Sea Squirts or Tunicates

Urochordate Characteristics  Have a non-living tunic  Most chordate features found in the free living acidian larva  Adults sessile filter feeders

Acidean Larva and Metamorphosis

Adult Urochordate

Subphylum Cephalochordata Lancelets

Cephalochordate Characteristics   Notochord and nerve cord found along entire length of body, persists throughout life   Fish-like in form Includes the lancelets (amphioxus)

Amphioxus

Subphylum Vertebrata The Vertebrates

Vertebrate Characteristics   Bony or cartilaginous vertebrae surrounding spinal cord   Notochord only in embryonic stages, persisting in some fishes   Two superclasses according to presence of jaws

Vertebrate Higher Classification  Superclass Agnatha - without jaws Class Myxini – hagfishes Class Myxini – hagfishes Class Cephalaspidomorphi – lampreys Class Cephalaspidomorphi – lampreys  Superclass Gnathostomata – with jaws Class Chondrichthyes – sharks, rays, chimaeras Class Chondrichthyes – sharks, rays, chimaeras Class Actinopterygii – ray-finned fishes Class Actinopterygii – ray-finned fishes Class Sarcopterygii – lobe-fin fishes Class Sarcopterygii – lobe-fin fishes Class Amphibia – frogs, salamanders Class Amphibia – frogs, salamanders Class Reptilia – snakes, lizards, crocodiles Class Reptilia – snakes, lizards, crocodiles Class Aves - birds Class Aves - birds Class Mammalia - mammals Class Mammalia - mammals