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
Figure 40.8 Internal exchange surfaces of complex animals
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
NOTOCHORD
tentacles
around mouth
segmented
muscles
midgut
TAIL
EXTENDING
PAST ANUS
aorta
gonad hindgut
pore of
atrial
cavity
anus
epidermis
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
• Agnathans
Figure 34.8 A hagfish
Tentacles
Gill slits (twelve pairs)
Mucous glands
Gill openings (seven pairs)
Fig. 27.7, p. 459
Figure 34.9 A sea lamprey
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
spiracle (small
gill slit)
Modern jawed fish (a shark)
jaw
support
jaw
Fig. 27.6, p. 458
In-text, p. 463
• Chondrichthyes
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)
Fig. 27.8, p. 460
• Osteichthyes
caudal
fin
dorsal fin
muscle segments
fin supports
brain
anal fin
pelvic fin
(one of two)
olfactory
heart bulb
pectoral fin
(one of two)
urinary
bladder
anus
kidney
swim bladder
liver
gallbladder
stomach
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
• Amphibians
Figure 34.17 Amphibian orders: Newt (left), frog (right)
Figure 34.17x1 Frogs
Fig. 27.12, p. 463
Figure 34.18 “Dual life” of a frog (Rana temporaria)
Amniotes
• Produce eggs with membranes
Figure 34.19 Amniotic egg
Figure 34.21 Taxonomic classes of amniotes
• Reptiles
Figure 34.22 A hatching reptile
olfactory lobe
(sense of smell)
forebrain, midbrain,
hindbrain regions
spinal
cord
vertebral
column
gonad
kidney
snout
unmatched rows of teeth
on upper and lower jaws
heart
stomach
intestine
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
Figure 34.24ax Sea turtle
hard shell
ribs of endoskeleton
Fig. 27.15, p. 466
Figure 34.24bx Banded gecko, Coleonyx varigatus
Figure 34.24cx Emerald tree boa
• birds
Fig. 27.16b, p. 468
Figure 34.25 Form fits function: the avian wind and feather
skull
barbule
barb
radius
shaft
ulna
pectoral
girdle
humerus
internal structure
of bird limb bones
pelvic
girdle
sternum
two main flight
muscles attached to
keel of sternum
Fig. 27.17, p. 469
Figure 34.26 A bald eagle in flight
Figure 34.27 Archaeopteryx, a Jurassic bird-reptile
Figure 34.27x Archaeopteryx
Figure 34.28a Cretaceous theropod dinosaurs with putative feathers from Chinese
sediments: Sinoauaropteryx
Figure 34.28b Cretaceous theropod dinosaurs with putative feathers from Chinese
sediments: Caudipteryx
Figure 34.29 A small sample of birds: Blue-footed boobies (top left), male peacock
(top right), penguins (bottom left), perching bird (bottom right)
Figure 34.29x Penguin march