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LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 34
The Origin and Evolution of
Vertebrates
Lectures by
Erin Barley
Kathleen Fitzpatrick
© 2011 Pearson Education, Inc.
Figure 34.1
• One lineage of vertebrates colonized land 365
million years ago
• There are about 52,000 species of vertebrates,
including the largest organisms ever to live on
the Earth (how many beetles were there?)
• Theme: Vertebrates have great disparity, a
wide range of differences within the group
– WHY?
© 2011 Pearson Education, Inc.
Concept 34.1: Chordates have a notochord
and a dorsal, hollow nerve cord
• Chordates (phylum Chordata) are bilaterian
animals that belong to the clade of animals known
as Deuterostomia
• Chordates comprise all vertebrates and two
groups of invertebrates, the urochordates and
cephalochordates
© 2011 Pearson Education, Inc.
Figure 34.2
We will explore 11 clades of the phylum Chordata
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
What do you notice that is odd?
Tetrapods
Amniotes
Amphibia
Figure 34.3
4 Derived Characters of Chordates
Dorsal,
hollow
nerve cord
Muscle
segments
Notochord
Mouth
Anus
Muscular,
post-anal tail
Pharyngeal
slits or clefts
Figure 34.4
Cephalochordata
Cirri
Mouth
Pharyngeal slits
Atrium
Notochord
1 cm
Digestive tract
Atriopore
Dorsal,
hollow
nerve cord
Segmental
muscles
Anus
Tail
• Lancelets (Cephalochordata)
are named for their bladelike
shape
• They are marine suspension
feeders that retain
characteristics of the
chordate body plan as adults
Figure 34.5
Urochordata
Notochord
Water flow
Dorsal, hollow
nerve cord
Tail
Muscle
segments
Excurrent
siphon
Incurrent
siphon
Intestine
Stomach
Atrium
Pharynx with slits
(a) Tunicate larva
Incurrent
siphon
to mouth
Excurrent
siphon
Excurrent
siphon
Anus
Intestine
Atrium
Pharynx
with
numerous
slits
Tunic
Esophagus
Stomach
(b) Adult tunicate
(c) Adult tunicate
• Tunicates (Urochordata) are more closely related to other
chordates than are lancelets
• When attacked, tunicates, or “sea squirts,” shoot water
through their excurrent siphon
Early Chordate Evolution
• Ancestral chordates may have resembled
lancelets
• The same Hox genes that organize the
vertebrate brain are expressed in the lancelet’s
simple nerve cord tip
• Genome sequencing suggests that
– Genes associated with the heart and thyroid are
common to all chordates
– Genes associated with transmission of nerve
impulses are unique to vertebrates
© 2011 Pearson Education, Inc.
Figure 34.8
5 mm
Segmented
muscles
Pharyngeal slits
Figure 34.9
Hagfishes
Slime glands
Hagfishes
• The most basal group of craniates is Myxini, the
hagfishes
• Hagfishes have a cartilaginous skull and axial rod
of cartilage derived from the notochord, but lack
jaws and vertebrae
• They have a small brain, eyes, ears, and tooth-like
formations
• Hagfishes are marine; most are bottom-dwelling
scavengers
© 2011 Pearson Education, Inc.
Figure 34.10
Lampreys
Lampreys
• Lampreys (Petromyzontida) represent the oldest
living lineage of vertebrates
• They are jawless vertebrates that feed by
clamping their mouth onto a live fish, suck blood
• They inhabit various marine and freshwater
habitats
• They have cartilaginous segments surrounding
the notochord and arching partly over the nerve
cord
© 2011 Pearson Education, Inc.
Figure 34.11
Conodonts were the first vertebrates with mineralized
skeletal elements
Dental elements
(within
head)
Concept 34.4: Gnathostomes are vertebrates
that have jaws
• Today, jawed vertebrates, or gnathostomes,
outnumber jawless vertebrates
• Gnathostomes include sharks and their relatives,
ray-finned fishes, lobe-finned fishes, amphibians,
reptiles (including birds), and mammals
© 2011 Pearson Education, Inc.
Figure 34.13
Gill slits
Cranium
Mouth
Skeletal rods
Figure 34.14 Fossil of an early gnathostome.
0.5 m
Figure 34.15
Dorsal fins
Chondrichthyans
(Sharks, Rays, and Their
Relatives)
Pectoral
Pelvic fins
fins
(a) Blacktip reef shark (Carcharhinus melanopterus)
(b) Southern stingray (Dasyatis americana)
(c) Spotted ratfish (Hydrolagus colliei)
Chondrichthyans (Sharks, Rays, and
Their Relatives)
• Chondrichthyans (Chondrichthyes) have a
skeleton composed primarily of cartilage
• The largest and most diverse group of
chondrichthyans includes the sharks, rays, and
skates
© 2011 Pearson Education, Inc.
• The reproductive tract, excretory system, and
digestive tract empty into a common cloaca
• Shark eggs are fertilized internally but embryos
can develop in different ways
– Oviparous: Eggs hatch outside the mother’s
body
– Ovoviviparous: The embryo develops within
the uterus and is nourished by the egg yolk
– Viviparous: The embryo develops within the
uterus and is nourished through a yolk sac
placenta from the mother’s blood
© 2011 Pearson Education, Inc.
Video: Shark Eating Seal
© 2011 Pearson Education, Inc.
Video: Manta Ray
© 2011 Pearson Education, Inc.
Ray-Finned Fishes and Lobe-Fins
• The vast majority of vertebrates belong to a clade
of gnathostomes called Osteichthyes
• Osteichthyans include the bony fish and
tetrapods
– Aquatic osteichthyans are the vertebrates we
informally call fishes
© 2011 Pearson Education, Inc.
Figure 34.16
Spinal cord
Swim
bladder
Dorsal fin
Adipose fin
Brain
Caudal
fin
Nostril
Cut
edge of
operculum
Anal fin
Liver
Gills
Anus
Stomach
Gonad
Kidney
Intestine
Heart
Pelvic
fin
Lateral
line
Urinary
bladder
Ray-Finned Fishes
• Actinopterygii, the ray-finned fishes, include
nearly all the familiar aquatic osteichthyans
• Ray-finned fishes originated during the Silurian
period (444 to 416 million years ago)
• The fins, supported mainly by long, flexible rays,
are modified for maneuvering, defense, and
other functions
© 2011 Pearson Education, Inc.
Video: Clownfish and Anemone
© 2011 Pearson Education, Inc.
Video: Coral Reef
© 2011 Pearson Education, Inc.
Video: Seahorse Camouflage
© 2011 Pearson Education, Inc.
Figure 34.17
Yellowfin tuna (Thunnus albacares)
Red
lionfish
(Pterois
volitans)
Common
sea horse
(Hippocampus
ramulosus)
Fine-spotted moray eel
(Gymnothorax dovii)
Figure 34.18
Lobe-Fins
5 cm
Lower
jaw
Scaly
covering
Dorsal
spine
• The lobe-fins (Sarcopterygii) have muscular pelvic and
pectoral fins
• Lobe-fins also originated in the Silurian period
Figure 34.19
Concept 34.5: Tetrapods are gnathostomes
that have limbs
• One of the most significant events in vertebrate
history was when the fins of some lobe-fins
evolved into the limbs and feet of tetrapods
© 2011 Pearson Education, Inc.
Derived Characters of Tetrapods
• Tetrapods have some specific adaptations
– Four limbs, and feet with digits
– A neck, which allows separate movement of
the head
– Fusion of the pelvic girdle to the backbone
– The absence of gills (except some aquatic
species)
– Ears for detecting airborne sounds
© 2011 Pearson Education, Inc.
Figure 34.20
Fish
Characters
Scales
Fins
Gills and
lungs
Tetrapod
Characters
Neck
Ribs
Fin skeleton
Flat skull
Eyes on top
of skull
Shoulder bones
Ribs
Neck
Scales
Head
Eyes on top of skull
Humerus
Ulna
Flat
skull
Elbow
Radius
Fin
“Wrist”
Fin skeleton
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 34.22
Amphibians
• Amphibians (class
Amphibia) are
represented by about
6,150 species
• Order Urodela
includes salamanders,
which have tails
(a) Order Urodela (salamanders)
(b) Order
Anura
(frogs)
(c) Order Apoda
(caecilians)
Figure 34.23
(a) Tadpole
(b) During metamorphosis
(c) Mating adults
• Amphibian means “both ways of life,” referring to
the metamorphosis of an aquatic larva into a
terrestrial adult
• Most amphibians have moist skin that
complements the lungs in gas exchange
• Amphibian populations have been declining in
recent decades…why are they so vulnerable?
© 2011 Pearson Education, Inc.
• Fertilization is external in most species, and the
eggs require a moist environment
• In some species, males or females care for the
eggs on their back, in their mouth, or in their
stomach
© 2011 Pearson Education, Inc.
Concept 34.6: Amniotes are tetrapods that
have a terrestrially adapted egg
• Amniotes are a group of tetrapods whose living
members are the reptiles, including birds, and
mammals
© 2011 Pearson Education, Inc.
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
Figure 34.26
Extraembryonic membranes
Allantois
Amnion
Chorion
Yolk sac
Embryo
Amniotic cavity
with amniotic
fluid
Shell
Yolk
(nutrients)
Albumen
Reptiles
• The reptile clade
includes the tuataras,
lizards, snakes, turtles,
crocodilians, birds, and
some extinct groups
• Reptiles have scales
that create a waterproof
barrier
• Most reptiles lay shelled
eggs on land
© 2011 Pearson Education, Inc.
• Most reptiles are ectothermic, absorbing
external heat as the main source of body heat
• Birds are endothermic, capable of keeping the
body warm through metabolism
© 2011 Pearson Education, Inc.
Figure 34.29
(a) Tuatara
(Sphenodon
punctatus)
(b) Australian
thorny devil
lizard (Moloch
horridus)
(c) Wagler’s pit viper
(Tropidolaemus wagleri)
(e) American alligator (Alligator mississippiensis)
(d) Eastern box turtle
(Terrapene carolina
carolina)
Birds
• Birds are archosaurs, but almost every feature of
their reptilian anatomy has undergone
modification in their adaptation to flight
© 2011 Pearson Education, Inc.
Derived Characters of Birds
• Many characters of birds are adaptations that
facilitate flight
• The major adaptation is wings with keratin
feathers
• Other adaptations include lack of a urinary
bladder, females with only one ovary, small
gonads, and loss of teeth
© 2011 Pearson Education, Inc.
Figure 34.30
Finger 1
(b) Bone structure
Palm
Finger 2
(a) Wing
Forearm
Shaft
Vane
Wrist
Finger 3
Shaft
Barb
Barbule
Hook
(c) Feather structure
Figure 34.31
Toothed beak
Airfoil wing
with contour
feathers
Wing claw
Long tail with
many vertebrae
• The demands of flight have rendered the general
body form of many flying birds similar to one another
Video: Flapping Geese
© 2011 Pearson Education, Inc.
Video: Soaring Hawk
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Video: Swans Taking Flight
© 2011 Pearson Education, Inc.
Figure 34.33
Behavior and morphology has adapted to fulfill distinct niches
Figure 34.34
Figure 34.35
Figure 34.36
Concept 34.7: Mammals are amniotes that
have hair and produce milk
• Mammals, class Mammalia, are represented by
more than 5,300 species
• Derived characters of mammals:
–
–
–
–
Mammary glands, which produce milk
Hair
A high metabolic rate, due to endothermy
A larger brain than other vertebrates of
equivalent size
– Differentiated teeth
•
© 2011 Pearson Education, Inc.
Figure 34.37
Biarmosuchus,
a synapsid
Key
Temporal
fenestra
Articular
Quadrate
Dentary
Squamosal
Jaw joint
(a) Articular and quadrate bones in the jaw
Middle ear
Stapes
Eardrum
Inner
ear
Eardrum
Middle ear
Inner ear
Stapes
Sound
Sound
Incus (quadrate)
Malleus (articular)
Present-day reptile
Present-day mammal
(b) Articular and quadrate bones in the middle ear
Figure 34.38
Monotremes
• Monotremes are a small group of egg-laying
mammals consisting of echidnas and the
platypus
Marsupials
• Marsupials include opossums, kangaroos, and
koalas
• The embryo develops within a placenta in the
mother’s uterus
• A marsupial is born very early in its development
• It completes its embryonic development while
nursing in a maternal pouch called a marsupium
© 2011 Pearson Education, Inc.
Figure 34.39
(a) A young brushtail possum
(b) Long-nosed bandicoot
Marsupial
mammals
Figure 34.40
Convergent
evolution of
marsupials
and eutherians
(placental
mammals).
Plantigale
Eutherian
mammals
Deer mouse
Mole
Marsupial mole
Sugar glider Flying
squirrel
Wombat
Tasmanian devil
Kangaroo
Woodchuck
Wolverine
Patagonian cavy
ANCESTRAL
MAMMAL
Monotremes Marsupials
(324 species)
(5 species)
Figure 34.41a
Monotremata
Marsupialia
Eutherians
(5,010 species)
Proboscidea
Sirenia
Tubulidentata
Hyracoidea
Afrosoricida
Macroscelidea
Xenarthra
Rodentia
Lagomorpha
Primates
Dermoptera
Scandentia
Carnivora
Cetartiodactyla
Perissodactyla
Chiroptera
Eulipotyphia
Pholidota
Figure 34.41b
Orders and Examples
Main Characteristics
Lay eggs; no nipples;
young suck milk from
fur of mother
Monotremata
Platypuses,
echidnas
Orders and Examples
Completes embryonic
development in pouch
on mother’s body
Marsupialia
Kangaroos,
opossums,
koalas
Echidna
Proboscidea
Elephants
Koala
Long, muscular trunk;
thick, loose skin; upper
incisors elongated
as tusks
Tubulidentata
Aardvarks
Teeth consisting of
many thin tubes
cemented together;
eats ants and termites
Aardvark
African elephant
Sirenia
Manatees,
dugongs
Aquatic; finlike forelimbs and no hind
limbs; herbivorous
Hyracoidea
Hyraxes
Manatee
Xenarthra
Sloths,
anteaters,
armadillos
Tamandua
Lagomorpha
Rabbits, hares,
picas
Jackrabbit
Carnivora
Dogs, wolves,
bears, cats,
weasels, otters,
seals, walruses
Rock hyrax
Short legs; stumpy
tail; herbivorous;
complex, multichambered stomach
Reduced teeth or no
teeth; herbivorous
(sloths) or carnivorous
(anteaters, armadillos)
Rodentia
Squirrels,
beavers, rats,
porcupines,
mice
Chisel-like incisors;
hind legs longer than
forelegs and adapted
for running and jumping;
herbivorous
Primates
Lemurs, monkeys,
chimpanzees,
gorillas,
Golden lion
humans
tamarin
Sharp, pointed canine
teeth and molars for
shearing; carnivorous
Perissodactyla
Hooves with an odd
Horses, zebras,
number of toes on
tapirs,
each foot; herbivorous
rhinoceroses
Indian rhinoceros
Hooves with an even
number of toes on each
foot; herbivorous
Chiroptera
Bats
Coyote
Cetartiodactyla
Artiodactyls
Sheep, pigs,
cattle, deer,
Bighorn sheep
giraffes
Cetaceans
Whales,
dolphins,
porpoises Pacific whitesided porpoise
Main Characteristics
Red squirrel
Frog-eating bat
Aquatic; streamlined body;
paddle-like fore-limbs and
no hind limbs; thick layer
of insulating blubber;
carnivorous
Eulipotyphla
“Core
insectivores”:
some moles,
some shrews
Chisel-like, continuously
growing incisors worn
down by gnawing;
herbivorous
Opposable thumbs;
forward-facing eyes;
well-developed cerebral
cortex; omnivorous
Adapted for flight;
broad skinfold that
extends from elongated
fingers to body and
legs; carnivorous or
herbivorous
Eat mainly insects
and other small
invertebrates
Star-nosed
mole
Video: Bat Licking Nectar
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Video: Bat Pollinating Agave Plant
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Video: Galápagos Sea Lion
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Video: Wolf Agonistic Behavior
© 2011 Pearson Education, Inc.
Derived Characters of Primates
–
–
–
–
Hands, feet for grasping
Flat nails
A large brain and short jaws
Forward-looking eyes close together on the
face, providing depth perception
– Complex social behavior and parental care
– A fully opposable thumb (in monkeys and
apes)
© 2011 Pearson Education, Inc.
Living Primates
• There are three main groups of living primates
– Lemurs, lorises, and pottos
– Tarsiers
– Anthropoids (monkeys and apes)
© 2011 Pearson Education, Inc.
Figure 34.42
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
Figure 34.44
(a) New World monkey:
spider monkey with prehensile tail
(b) Old World monkey: macaque
Video: Gibbons Brachiating
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Video: Chimp Agonistic Behavior
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Video: Chimp Cracking Nut
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Figure 34.45
(a) Gibbon
(b) Orangutan
(c) Gorilla
(d) Chimpanzees
(e) Bonobos
Concept 34.8: Humans are mammals that
have a large brain and bipedal locomotion
• The species Homo sapiens is about 200,000
years old, which is very young, considering that
life has existed on Earth for at least 3.5 billion
years
© 2011 Pearson Education, Inc.
Derived Characters of Humans
• A number of characters distinguish humans from
other apes
– Upright posture and bipedal locomotion
– Larger brains capable of language, symbolic
thought, artistic expression, the manufacture
and use of complex tools
– Reduced jawbones and jaw muscles
– Shorter digestive tract
© 2011 Pearson Education, Inc.
• The human and chimpanzee genomes are 99%
identical
• How can we be this close, yet so different?
© 2011 Pearson Education, Inc.
Figure 34.46
Paranthropus
robustus
0
?
Paranthropus
boisei
0.5
Homo
Homo
neanderthalensis sapiens
Homo
ergaster
1.0
Australopithecus
africanus
Millions of years ago
1.5
2.0
2.5
Kenyanthropus
platyops
Australopithecus
garhi
Australo3.0 pithecus
anamensis
3.5
Homo
habilis
4.0
4.5
6.0
6.5
7.0
Ardipithecus ramidus
Orrorin tugensis
Sahelanthropus
tchadensis
Homo
rudolfensis
• Hominins originated in
Africa about 6–7 million
years ago
• Early hominins show
evidence of small brains
and increasing bipedalism
Australopithecus
afarensis
5.0
5.5
Homo erectus
Figure 34.47: Ardi, 4.4 million years old
• Misconception: Early hominins were
chimpanzees
– Correction: Hominins and chimpanzees shared
a common ancestor
• Misconception: Human evolution is like a ladder
leading directly to Homo sapiens
– Correction: Hominin evolution included many
branches or coexisting species, though only
humans survive today
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Australopiths
• Australopiths are a paraphyletic assemblage of
hominins living between 4 and 2 million years ago
• Some species, such as Australopithecus
afarensis walked fully erect
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Figure 34.48 Evidence that hominins walked upright 3.5 million years ago.
(a) The Laetoli footprints
(b) Artist’s reconstruction of A. afarensis
• Homo erectus originated in Africa by 1.8 million
years ago
• It was the first hominin to leave Africa
© 2011 Pearson Education, Inc.
Neanderthals
• Neanderthals, Homo neanderthalensis, lived in
Europe and the Near East from 350,000 to
28,000 years ago
• They were thick-boned with a larger brain, they
buried their dead, and they made hunting tools
• Debate is ongoing about the extent to which
genetic material was exchanged between
neanderthals and Homo sapiens
© 2011 Pearson Education, Inc.
Figure 34.50
EXPERIMENT
Hypothesis: Neanderthals gave rise to European humans.
Expected
phylogeny:
Chimpanzees
Neanderthals
Living Europeans
Other living humans
RESULTS
Chimpanzees
Neanderthal 1
Neanderthal 2
European and other
living humans
Homo Sapiens
• Homo sapiens appeared in Africa by 195,000
years ago
• All living humans are descended from these
African ancestors
© 2011 Pearson Education, Inc.
Figure 34.51
• The oldest fossils of Homo sapiens outside Africa
date back about 115,000 years and are from the
Middle East
• Humans first arrived in the New World sometime
before 15,000 years ago
• In 2004, 18,000-year-old fossils were found in
Indonesia, and a new small hominin was named:
Homo floresiensis
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• Homo sapiens were the first group to show
evidence of symbolic and sophisticated thought
• In 2002, a 77,000-year-old artistic carving was
found in South Africa
© 2011 Pearson Education, Inc.
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
Craniates: two sets of Hox
genes, neural crest
Chordates: notochord; dorsal, hollow
nerve cord; pharyngeal slits; post-anal tail
Figure 34.UN10
Clade
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)