Figure 34.2
Echinodermata
Chordates
Cephalochordata
ANCESTRAL
DEUTEROSTOME
Urochordata
Notochord
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Myxini
Common
ancestor of
chordates
Head
Petromyzontida
Chondrichthyes
Vertebral column
Actinopterygii
Jaws, mineralized skeleton
Actinistia
Lungs or lung derivatives
Dipnoi
Lobed fins
Reptilia
Limbs with digits
Amniotic egg
Mammalia
Milk
Tetrapods
Amniotes
Amphibia
Figure 34.2a
Echinodermata
ANCESTRAL
DEUTEROSTOME
Cephalochordata
Urochordata
Notochord
Common
ancestor of
chordates
Head
Myxini
Petromyzontida
Chondrichthyes
Vertebral column
Jaws, mineralized skeleton
Osteichthyes
Figure 34.2b
Actinopterygii
Actinistia
Lungs or lung derivatives
Dipnoi
Lobed fins
Amphibia
Reptilia
Limbs with digits
Amniotic egg
Mammalia
Milk
Chordate characteristics
Subphylum Urochordata: a tunicate
Subphylum Cephalochordata: lancelet anatomy
Subphylum Cephalochordata: the lancelet Branchiostoma
The neural crest, embryonic source of many unique vertebrate characters
Figure 34.2
Echinodermata
Chordates
Cephalochordata
ANCESTRAL
DEUTEROSTOME
Urochordata
Notochord
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Myxini
Common
ancestor of
chordates
Head
Petromyzontida
Chondrichthyes
Vertebral column
Actinopterygii
Jaws, mineralized skeleton
Actinistia
Lungs or lung derivatives
Dipnoi
Lobed fins
Reptilia
Limbs with digits
Amniotic egg
Mammalia
Milk
Tetrapods
Amniotes
Amphibia
A hagfish
A sea lamprey
Hypothesis for the evolution of vertebrate jaws
Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern
stingray (bottom left), blue spotted stingray (bottom right)
Anatomy of a trout, a representative ray-finned fish
A coelocanth (Latimeria), the only extant lobe-finned genus
Figure 34.2b
Actinopterygii
Actinistia
Lungs or lung derivatives
Dipnoi
Lobed fins
Amphibia
Reptilia
Limbs with digits
Amniotic egg
Mammalia
Milk
Figure 34.21
Lungfishes
Eusthenopteron
Panderichthys
Tiktaalik
Acanthostega
Limbs
with digits
Tulerpeton
Amphibians
Amniotes
Silurian
PALEOZOIC
Permian
Carboniferous
Devonian
415 400 385 370 355 340 325 310 295 280 265 0
Time (millions of years ago)
Key to
limb bones
Ulna
Radius
Humerus
Figure 34.17x1 Frogs
Figure 34.25
Parareptiles
Turtles
Reptiles
Archosaurs
Crocodilians
Pterosaurs
Saurischians
Dinosaurs
Diapsids
Ornithischian
dinosaurs
Saurischian dinosaurs
other than birds
Birds
Plesiosaurs
ANCESTRAL
AMNIOTE
Ichthyosaurs
Synapsids
Lepidosaurs
Tuataras
Squamates
Mammals
Amniotic egg
Extant reptiles: Desert tortoise (top left), lizard (top right), king snake (bottom left), alligators (bottom right)
Form fits function: the avian wind and feather
Archaeopteryx, a Jurassic bird-reptile
A small sample of birds: Blue-footed boobies (top left), male peacock (top right), penguins (bottom left),
perching bird (bottom right)
Figure 34.30 Evolution of the mammalian jaw and ear bones
Australian monotremes and marsupials: echidna (top left), marsupial mouse (lower left), sugar glider
(right)
Figure 34.41a
Marsupials
Monotremes
(5 species) (324 species)
ANCESTRAL
MAMMAL
Monotremata
Marsupialia
Eutherians
(5,010 species)
Proboscidea
Sirenia
Tubulidentata
Hyracoidea
Afrosoricida
Macroscelidea
Xenarthra
Rodentia
Lagomorpha
Primates
Dermoptera
Scandentia
Carnivora
Cetartiodactyla
Perissodactyla
Chiroptera
Eulipotyphia
Pholidota
ORDERS
AND EXAMPLES
Monotremata
Platypuses,
echidnas
MAIN
CHARACTERISTICS
Lay eggs; no
nipples; young
suck milk from
fur of mother
ORDERS
AND EXAMPLES
Marsupialia
Kangaroos,
opossums,
koalas
Echidna
Proboscidea
Elephants
African elephant
Sirenia
Manatees,
dugongs
Xenarthra
Sloths,
anteaters,
armadillos
Manatee
Tamandua
Lagomorpha
Rabbits,
hares, picas
Jackrabbit
Carnivora
Dogs, wolves,
bears, cats,
weasels, otters,
Coyote
seals, walruses
Cetartiodactyla
Artiodactyls
Sheep, pigs
cattle, deer,
giraffes
Bighorn sheep
Cetaceans
Whales,
dolphins,
porpoises
Pacific whitesided porpoise
MAIN
CHARACTERISTICS
Embryo completes
development in
pouch on mother
Koala
Teeth consisting of
many thin tubes
cemented together;
eats ants and termites
Long, muscular
trunk; thick,
loose skin; upper
incisors elongated
as tusks
Tubulidentata
Aardvark
Aquatic; finlike
forelimbs and
no hind limbs;
herbivorous
Hyracoidea
Hyraxes
Reduced teeth or
no teeth; herbivorous
(sloths) or carnivorous
(anteaters,
armadillos)
Chisel-like incisors;
hind legs longer than
forelegs and adapted
for running and
jumping
Rodentia
Squirrels,
beavers, rats,
porcupines,
Red squirrel
mice
Primates
Lemurs,
monkeys,
apes,
Golden lion
humans
tamarin
Aardvark
Rock hyrax
Sharp, pointed canine
teeth and molars for
shearing; carnivorous
Perissodactyla
Horses,
zebras, tapirs,
rhinoceroses
Indian rhinoceros
Hooves with an
even number
of toes on each
foot; herbivorous
Chiroptera
Bats
Aquatic; streamlined
body; paddle-like
forelimbs and no
hind limbs; thick
layer of insulating
blubber; carnivorous
Frog-eating bat
Eulipotyphla
“Core insectivores”: some
moles, some
Star-nosed
shrews
mole
Short legs; stumpy tail;
herbivorous; complex,
multichambered
stomach
Chisel-like, continuously
growing incisors worn
down by gnawing;
herbivorous
Opposable thumbs;
forward-facing eyes;
well-developed
cerebral cortex;
omnivorous
Hooves with an
odd number of toes
on each foot;
herbivorous
Adapted for flight; broad
skinfold that extends
from elongated fingers
to body and legs;
carnivorous or
herbivorous
Diet consists mainly
of insects and other
small invertebrates
Figure 34.43
Lemurs, lorises,
and bush babies
Tarsiers
ANCESTRAL
PRIMATE
Old World monkeys
Gibbons
Orangutans
Gorillas
Chimpanzees
and bonobos
Humans
60
50
20
30
40
Time (millions of years ago)
10
0
Anthropoids
New World monkeys
Prosimians:Lemurs
A capuchin, a New World monkey (left), and a vervet, an Old World monkey (right)
Apes: Gibbon (top left), orangutan (top right), gorilla (bottom left), chimpanzee (bottom right)
A timeline for some hominid species
Upright posture predates an enlarged brain in human evolution
Amniotes: amniotic egg, rib cage ventilation
Lobe-fins: muscular fins or limbs
Tetrapods: four limbs, neck, fused
pelvic girdle
Osteichthyans: bony skeleton
Gnathostomes: hinged jaws, four sets of Hox genes
Vertebrates: Dix genes duplication,
backbone of vertebrae
Clade
Craniates: two sets of Hox
genes, neural crest
Chordates: notochord; dorsal, hollow
nerve cord; pharyngeal slits; post-anal tail
Figure 34.UN10
Description
Cephalochordata
(lancelets)
Basal chordates; marine suspension feeders that
exhibit four key derived characters of chordates
Urochordata
(tunicates)
Marine suspension feeders; larvae display the
derived traits of chordates
Myxini
(hagfishes and
relatives)
Jawless marine organisms; have head that includes
a skull and brain, eyes, and other sensory organs
Petromyzontida
(lampreys)
Jawless vertebrates; typically feed by attaching to a
live fish and ingesting its blood
Chondrichthyes
(sharks, rays,
skates, ratfishes)
Actinopterygii
(ray-finned fishes)
Aquatic gnathostomes; have cartilaginous skeleton,
a derived trait formed by the reduction of an
ancestral mineralized skeleton
Aquatic gnathostomes; have bony skeleton and
maneuverable fins supported by rays
Actinistia
(coelacanths)
Dipnoi
(lungfishes)
Ancient lineage of aquatic lobe-fins still surviving
in Indian Ocean
Freshwater lobe-fins with both lungs and gills; sister
group of tetrapods
Amphibia
(salamanders,
frogs, caecilians)
Have four limbs descended from modified fins; most
have moist skin that functions in gas exchange; many
live both in water (as larvae) and on land (as adults)
Reptilia
(tuataras, lizards
and snakes, turtles,
crocodilians, birds)
One of two groups of living amniotes; have amniotic
eggs and rib cage ventilation, key adaptations for life
on land
Mammalia
(monotremes,
marsupials,
eutherians)
Evolved from synapsid ancestors; include egg-laying
monotremes (echidnas, platypus); pouched marsupials
(such as kangaroos, opossums); and eutherians
(placental mammals, such as rodents, primates)