Phylum Chordata
Subphylum Urochordata –
 Subphylum Cephalochordata –
 Subphylum Vertebrata –

 48,000
species
 Range in size from tiny fish to huge whales
 Occupy all of Earth’s biomes
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Craniates

2 defining characteristics compared to
nonvertebrate chordates
1.
2.

_____________- embryonic cells that
will disperse throughout the embryo
contributing to the development of the
skeleton, nerves, jaws, and teeth
Also, at least 2 Hox clusters
2
Class ___________




___________, finless,
marine fish that lack
vertebrae
Essentially blind with
a keen sense of ____
Copious amounts of
________
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Vertebrates

1.
2.
3.
All chordate and craniate characteristics plus
_____________- notochord is replaced by a
bony or cartilaginous column of interlocking
vertebrae
______________ of cartilage or bone – most
also have two pairs of appendages
Internal organs - liver, kidneys, endocrine
glands, and a heart with at least two chambers


Heart, kidneys, and endocrine system are more
complex than analogous structures in other taxa
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The fish
Key innovation in vertebrate evolution is
_____________________
 Developed first in ______
 Agnathans –
 Gnathostomes – ________ with 2
additional Hox clusters

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Class ____________________






____________________and true appendages
Do possess a ____________ and rudimentary
_______________________
One of the most primitive groups of vertebrates
Found in marine and freshwater
Marine lampreys ___________ as adults
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7


Hinged jaws developed from the pharnygeal
arches
Descent with modification
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Class ____________________

Sharks, skates, rays
 Skelton composed of _______________

 Derived

not ancestral character
Sharks among earliest fish to develop
teeth

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
Denser than water –
2 chambered heart – single circulation
 Powerful sense of _______
 Lateral line –
 Internal fertilization

– lay eggs
 ___________ – egg retained in female, no
placenta
 ___________ – eggs develop in uterus,
placenta nourishes young
 ___________
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Bony fish

3 living classes
______________ – ray-finned fish
 ______________ – coelacanths
 ______________ – lungfish


3 features different from Chondricthyes
1.
2.
3.
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13

Actinopterygii – ray-finned fish
 Includes
all bony fish but __________ and
__________
 Fins supported by thin…
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
_______________ – coelacanths
 Believed
extinct until ________
 Special joint in skull gives powerful bite
 Instead of vertebral column has hollow
notochord filled with oil-like fluid
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
___________ – lungfish
3
genera with 6 species
 Live in…
 Both …
 Will drown if unable to breathe air
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Tetrapods

Transition to land meant adaptations to
prevent desiccation and locomotion and
reproduction on land possible

Vertebral column strengthened, _______
________ bones braced against backbone
 Relatively simple changes in gene
expression, especially …

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




Transitional taxa
____________ –
retained adaptations
for aquatic life – stem
species
Species increasingly
fed on land but tied to
water for reproduction
Vertebral column and
hip and shoulder
bones grew even
sturdier
Evolution of rib cage
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Davis, Capecchi, and Colleagues Showed a
Genetic-Developmental Explanation for Limb Length
in Tetrapods
Specific Hox genes are responsible for
determining limb formation in mice
 Mutations in the genes HoxA-11 and HoxD11 resulted in the loss of the radius, ulna,
and some of the carpals
 Relatively simple mutations can control
relatively large changes in limb
development

Amphibians

Successfully invaded land but must return

Buccal pumping to force air into lungs

3 chambered heart
 Fertilization external



Metamorphosis regulated by thyroid
hormones
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
Order __________ – frog and toads
 Nearly
______ of amphibians


Order __________ – salamanders
 Paedomorphosis
– adult has larval
characteristics

Order _____________ – caecilians
 Legless,
nearly blind tropical
 Secondarily legless
 Uterine milk nourishes young inside mother’s
body
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_______________

Critical innovation was the development of
a…

Amniotic egg broke tie to water
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
1.
2.
3.
4.
4 extraembryonic
membranes
___________ –
protects embryo
in amniotic cavity
_________ – yolk
_________ –
disposal of wastes
_________ – with
allantois for gas
exchange
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
Other key innovations
 ________________
resistant skin
 ________________ – negative pressure
sucks air in
 _______________________________ –
concentrate waste prior to elimination

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_______________________
Classification under revision
 One class or four?
 Class
 Class
 Class
 Class

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Class _____________





Virtually unchanged
for 200 million years
Hard protective shell
In most…
Lack _________ but
have sharp beak
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Class ___________________



____________ with
extremely mobile
joints
Lizards have …
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Class _________________





Crocodiles and alligators
Essentially unchanged for 200 million years
4 chambered heart
Teeth in sockets
Care for young
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Dinosaurs



Class ___________ – bird-hipped dinosaurs
Class ___________ – lizard-hipped dinosaurs
Legs of dinosaurs were positioned directly under
the body
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The Differentiation of Scales, Feathers, and
Fur May Be Caused by Simple Changes in
Developmental Pathways
Epithelial appendages (scales, feathers, hair,
fur) look different but share similarities in
initial development
 All originate as epithelial placodes
 Timing and expression of regulatory
molecules determines the appendage that
develops in the dermal layer


______________ lithographica
 Except


for feathers very similar to dinosaurs
______________ zoui
______________ sanctus
 Completely
feathered, lacking bony tail and toothed jaw
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Class _____________

4 features unique to birds (for flight)
1.
2.
_____________________ – thin, hollow,
honeycombed

3.
4.
_________ to anchor flight muscles, no teeth
_______________ – very efficient
breathing
___________________ – single ovary,
no urinary bladder
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Double circulation with 4 chambered heart
 Acute vision



Eggs brooded


28 orders, 9600 species
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________________
Evolved from amniote ancestors earlier
than birds
 Appeared about 220 mya
 _________________________ mammals
flourished
 Range of…

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
Distinguishing characters


 Only
vertebrates with …
 Skull


Pinnae, external ears
 Brain enlarged in large skull

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
Some but not all mammals
 Digest
plants using …
 Horns and antlers
Horns –
 Antlers –

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
Subclass __________ – Order
______________
 __________________lay
eggs, lack placenta,
poorly developed nipples

Subclass __________ – ______________
7
orders
 Once widespread, now confined mostly to
____________
 ____________ found in North America
 Very undeveloped young must make it to
____________ to finish development
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
Subclass _________


 Placenta
provides _____________
 18 orders
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Primates
Primarily tree-dwelling species
 Evolved about 85 mya
 Defining characteristics



 Some
digits have…
 Binocular vision
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
______________
 Bush
babies, lemurs, pottos, tarsiers
 Generally nocturnal and smaller-brained

______________
 Monkeys

Tails, monkeys cannot swing from branch to
branch
– gibbons, gorillas,
orangutans, chimpanzees and humans
 ______________

Family Hylobatidae – lesser apes or gibbons
 Family Hominidae – greater apes

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Humans
Related to chimpanzees and apes but
not…
 All hominoids shared a common ancestor
 _________ lineage leading to humans
separated from other primates
 1 or 2 hominid species coexisting at one
time

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________ resulted in many changes –
spine sits underneath skull, broader pelvis,
lower limbs larger
 ___________________ – widespread, at
least 6 species, relatively small, facial
structure and brain size similar to chimp
 ______ – increased brain size, stone tools

 Homo
sapiens 3,000 years ago
 Taller, lighter-weight, slightly smaller brain
capacity than H. neanderthalensis
 ____________hypothesis supported over
multiregional hypothesis
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