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Chordates . Notocord Dorsal hollow nerve cord Gills Postanal tail. Figure 34.0 A snake skeleton exhibits defining characteristic of a vertebrate. Figure 34.2 Chordate characteristics. Figure 34.3 Subphylum Urochordata: a tunicate.
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Chordates Notocord Dorsal hollow nerve cord Gills Postanal tail
Figure 34.0 A snake skeleton exhibits defining characteristic of a vertebrate
nerve cord notochord gut oral opening atrial opening (water that passed through pharynx leaves this way) pharynx with gill slits Fig. 27.3, p. 457
Figure 34.4b Subphylum Cephalochordata: the lancelet Branchiostoma
DORSAL, TUBULAR NERVE CORD PHARYNX WITH GILL SLITS TAIL EXTENDING PAST ANUS NOTOCHORD aorta anus epidermis pore of atrial cavity gonad hindgut segmented muscles tentacles around mouth midgut segmented muscles Fig. 27.4, p. 457
Figure 34.5 Early fossil vertebrates: Haikouella (top), Myllokunmingia (bottom)
Figure 34.6 The neural crest, embryonic source of many unique vertebrate characters
Tentacles Gill slits (twelve pairs) Mucous glands Gill openings (seven pairs) Fig. 27.7, p. 459
Figure 34.10 Hypothesis for the evolution of vertebrate jaws
supporting structures Early jawless fish (an agnathan) gill slit Early jawed fish (a placoderm) jaw jaw support spiracle (small gill slit) Modern jawed fish (a shark) jaw Fig. 27.6, p. 458
Figure 34.11 Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern stingray (bottom left), blue spotted stingray (bottom right)
dorsal fin caudal fin muscle segments fin supports brain anal fin olfactory bulb pectoral fin (one of two) pelvic fin (one of two) heart liver anus gallbladder urinary bladder kidney stomach swim bladder intestine Fig. 27.9, p. 461
Figure 34.12a Ray-finned fishes (class Actinopterygii): yellow perch
Figure 34.12b Ray-finned fishes (class Actinopterygii): long-snouted sea horse
Figure 34.13 Anatomy of a trout, a representative ray-finned fish
Figure 34.14 A coelocanth (Latimeria), the only extant lobe-finned genus
Figure 34.16 Skeleton of Acanthostega, a Devonian tetrapod fish
Amniotes • Produce eggs with membranes
olfactory lobe (sense of smell) vertebral column gonad spinal cord forebrain, midbrain, hindbrain regions kidney snout intestine heart unmatched rows of teeth on upper and lower jaws stomach cloaca esophagus liver Fig. 27.13, p. 464
Figure 34.24 Extant reptiles: Desert tortoise (top left), lizard (top right), king snake (bottom left), alligators (bottom right)
venom gland hollow fang Fig. 27.15, p. 466
ribs of endoskeleton hard shell Fig. 27.15, p. 466
skull barbule barb radius shaft pectoral girdle ulna internal structure of bird limb bones humerus pelvic girdle sternum two main flight muscles attached to keel of sternum Fig. 27.17, p. 469