Vertebrates
Chapter 34
Arthropoda
Nematoda
Rotifera
Annelida
Mollusca
Nemertea
Platyhelminthes
Ectoprocta
Phoronida
Brachiopoda
Chordata
Echinodermata
Cnidaria
Ctenophora
Silicarea
Calcarea
“Radiata”
“Porifera”
The Animal
Kingdom
~ 35 phyla
>95% inverts.
Deuterostomia
Lophotrochozoa
Ecdysozoa
<5% verts.
Bilateria
Eumetazoa
Metazoa
Ancestral colonial
flagellate
Fig. 32.11
&
Table 33.7
Deuterostomia
P. Chordata
Notochord –
attachment
site for
muscles
Lancelet (adult)
Human embryo (5 weeks)
Deuterostomia
P. Chordata
Notochord –
attachment
site for
muscles
Lancelet (adult)
Dorsal, hollow
nerve cord –
one end forms
the brain (if
present)
Human embryo (5 weeks)
Deuterostomia
P. Chordata
Notochord –
attachment
site for
muscles
Lancelet (adult)
Pharyngeal gill
slits
Dorsal, hollow
nerve cord –
one end forms
the brain (if
present)
Human embryo (5 weeks)
Deuterostomia
P. Chordata
Notochord –
attachment
site for
muscles
Lancelet (adult)
Pharyngeal gill
slits
Dorsal, hollow
nerve cord –
one end forms
the brain (if
present)
Postanal
tail
Human embryo (5 weeks)
P. Chordata
Invertebrate subphyla:
Urochordata
Cephalochordata
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Urochordata
(tunicates)
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Tunicates; a.k.a. sea squirts
Subphylum Urochordata
P. Chordata
Subphylum Urochordata
Tunicates; a.k.a. sea squirts
The key shared derived characters of chordates are
found in the larval stage
adults
P. Chordata
Subphylum Cephalochordata
Lancelets
The key shared derived characters of chordates are
found in the adult stage
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Craniates:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
A key shared derived
character: neural crest,
which gives rise
developmentally to
cartilage or bones of
the skull
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Vertebral column
Head
Brain
Hagfishes
Vertebrates
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class “hagfishes”
Cartilaginous skull
and notochord
No vertebrae
No jaws
No paired
appendages
P. Chordata
Vertebrates:
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Lampreys
Gnathostomes
A key shared derived
character: vertebrae
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Urochordata
(tunicates)
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class “lampreys”
Cartilaginous skeleton,
including a structure
surrounding the notochord
with rudimentary vertebrae
No jaws
No paired
appendages
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Gnathostomes:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Key shared derived
characters: hinged
jaws and mineralization
of skeleton
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Chondrichthyes
Osteichthyans
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class Chondrichthyes
Over 750
species of
sharks,
skates,
rays…
P. Chordata
Class Chondrichthyes
… and
ratfish, or
chimaeras
P. Chordata
Class Chondrichthyes
Notochord present only in
embryos
Predominantly cartilaginous
skeleton
Respire through gills
Lateral line system for
detecting pressure changes
2-chambered heart
P. Chordata
Class Chondrichthyes
Oviparous – embryonic
development fueled from
nutrients supplied by yolk, and
the unshelled eggs hatch outside
the mother’s body
Ovoviviparous – embryonic
development fueled by yolk, but the
eggs hatch inside the mother’s body
Viviparous – embryonic development
fueled by mother’s blood through a
placenta; live birth
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Osteichthyans:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Key shared derived
character: ossified
skeleton (hard matrix of
calcium phosphate)
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Ray-finned fishes
Lobe-fins
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class “ray-finned fishes”
Very diverse group; over
30,000 extant species
P. Chordata
Class “ray-finned fishes”
Notochord present only in
embryos
Ossified (bony) skeleton
Respire through gills
Lateral line system for
detecting pressure changes
2-chambered heart
Swim bladder – air-filled sac that
helps control buoyancy
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Lobe-fins:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Key shared derived
character: rod-shaped
bones in fins or limbs
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Coelacanths
Lungfishes
Tetrapods
Jaws, mineralized skeleton
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class “coelacanths”
coelocanth
P. Chordata
Class “lungfishes”
Respiration through gills supplemented by lungs
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Tetrapods:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Key shared derived
character: limbs in
place of pectoral and
pelvic fins
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Amphibia
Amniotes
Vertebral column
Head
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
P. Chordata
Class Amphibia
“Two lives”
Larvae generally aquatic,
adults generally terrestrial
P. Chordata
Class Amphibia
“Two lives”
Larvae generally aquatic,
adults generally terrestrial
Bony skeleton
3-chambered heart
Generally respire through
lungs as adults,
supplemented by gas
exchange through the skin
P. Chordata
Class Amphibia
“Two lives”
External fertilization is common
Eggs lack a shell and are
prone to desiccation
Over 4,800 extant species
P. Chordata
Class Amphibia
Order Anura (“tail-less
ones”) – frogs, toads
P. Chordata
Class Amphibia
Order Urodela (“tailed
ones”) – salamanders,
newts
P. Chordata
Class Amphibia
Order Apoda (“legless
ones”) – caecilians
Mammalia
(mammals)
Reptilia
(turtles, snakes,
crocodiles, birds)
Amphibia
(frogs, salamanders)
Dipnoi
(lungfishes)
Actinistia
(coelacanths)
Actinopterygii
(ray-finned fishes)
Chordates
Craniates
Vertebrates
Gnathostomes
Osteichthyans
Lobe-fins
Tetrapods
Amniotes
Chondrichthyes
(sharks, rays, chimaeras)
Cephalaspidomorphi
(lampreys)
Myxini
(hagfishes)
Cephalochordata
(lancelets)
Amniotes:
Urochordata
(tunicates)
P. Chordata
Echinodermata
(sister group to chordates)
Deuterostomia
Milk
Key shared derived
character: amniotic
egg, which contains
specialized
extraembryonic
membranes
Amniotic egg
Legs
Lobed fins
Lungs or lung derivatives
Jaws, mineralized skeleton
Vertebral column
Head
Reptilia
Mammalia
Brain
Notochord
Ancestral deuterostome
Fig. 34.2
Deuterostomia
P. Chordata
Amniotes:
Saurischians
Key shared derived
character: amniotic
egg, which contains
specialized
extraembryonic
membranes
Dinosaurs
Lepidosaurs
Archosaurs
Synapsids
Diapsids
Reptilia
Reptilia
Mammalia
Ancestral
amniote
Fig. 34.23
Extraembryonic membranes (and a shell in many species) are
not part of the embryo’s body, and aid gas exchange, waste
storage, and nutrition
Fig. 34.24
P. Chordata
Reptilia
About 6,500 extant
species (excluding birds)
Leathery shell around
egg
3-chambered heart (4 in
crocodilians)
Scales
Ectothermic
Internal fertilization
P. Chordata
Reptilia
E.g., turtles, tortoises
P. Chordata
Reptilia
E.g., squamates
(snakes and lizards)
P. Chordata
Reptilia
E.g., crocodilians
P. Chordata
Birds
About 8,600 extant species,
in about 28 orders
Eggs with hard shells (calcium
carbonate)
Feathers – highly modified scales
Endothermic
4-chambered heart
P. Chordata
Birds
Clear genetic, morphological, and
fossil evidence for phylogenetic
nesting within Reptilia
Archaeopteryx
Cassowary
P. Chordata
Class Aves
Some groups lost the
ability to fly
Penguins
Emu
Kiwi
Deuterostomia
P. Chordata
For Reptilia to be
monophyletic, it
must contain the
birds
Saurischians
Dinosaurs
Lepidosaurs
Archosaurs
Synapsids
Diapsids
Reptiles
Ancestral
amniote
Fig. 34.23
Deuterostomia
P. Chordata
Now let’s consider
the mammals…
Saurischians
Dinosaurs
Lepidosaurs
Archosaurs
Synapsids
Diapsids
Reptiles
Ancestral
amniote
Fig. 34.23
P. Chordata
Mammalia
About 4,500 extant species in about
16 orders
Hair
Endothermic
4-chambered heart
Mammary glands
Differentiated, specialized teeth
P. Chordata
Mammalia
Monotremes
Egg-laying mammals
Fig. 34.36
P. Chordata
Mammalia
Monotremes
Platypus
P. Chordata
Mammalia
Monotremes
Echidna
P. Chordata
Mammalia
Marsupials
Embryonic development occurs
outside the mother, often in a
marsupium
Fig. 34.36
P. Chordata
Mammalia
At birth
After 17
weeks in
pouch
Marsupials
Embryonic development occurs
outside the mother, often in a
marsupium
P. Chordata
Mammalia
Marsupials
P. Chordata
Mammalia
Eutherians (Placental Mammals)
Embryonic development occurs inside
the mother’s uterus, joined by the
placenta
African origin
S. American
& radiation
radiation
Fig. 34.36
P. Chordata
Mammalia
Eutherians (Placental Mammals)
Embryonic development occurs inside
the mother’s uterus, joined by the
placenta
P. Chordata
Mammalia
Eutherians (Placental Mammals)
Carnivores, herbivores, etc.
P. Chordata
Mammalia
Eutherians (Placental Mammals)
Terrestrial, freshwater, marine…
P. Chordata
Mammalia
Eutherians (Placental Mammals)
Some are even volant!
Millions of years ago
10
60
Ancestral primate
0
Humans
Chimpanzees
Gorillas
Orangutans
Gibbons
Old World monkeys
New World monkeys
Tarsiers
Lemurs, lorises, and pottos
P. Chordata
Mammalia, Order Primates
A special group
(from our human
perspective)
20
30
40
50
Fig. 34.38
Millions of years ago
10
60
20
Ancestral primate
0
Humans
Chimpanzees
Gorillas
Orangutans
Gibbons
Old World monkeys
New World monkeys
Tarsiers
Lemurs, lorises, and pottos
P. Chordata
Mammalia, Order Primates
Humans:
Opposable thumbs
Highly developed
cerebral cortex
30
40
50
Fig. 34.38