Phylum Chordata
•
•
•
•
Notochord in embyronic stage
Dorsal hollow nerve cord
Pharyngeal slits
Muscular, post anal tail
• Tunicates:
Urochordata
most primal form of all vertebrates
•pharyngeal gill slits
•Dorsal nerve cord
•notochord
•separate mouth and anus.
Circulatory System
• Ventral Heart  Arteries  Arterioles 
Capillaries  Venules  Veins
Fish Heart
Amphibian heart
Mammal
Heart
What
vertebrates do
not have bones?
Agnatha
Class Myxini
Class Cephalaspidomorphi
Ostracoderms
• Conodonts – Extinct
• Date back to 510 mya
• Cone shaped teeth
like structures that
were ossified
• Placoderm - Extinct
jawed, armored fish
• Abundant during
Devonian
• No teeth, but jaws
had tusklike
projections
Class Chondricthyes
Class Actinopterygii
Osteichthyes
Class Dipnoi
Class Actinistia
Amphibia
“dual life”
• Carboniferous  “Age of
Amphibians”
• 3 orders
– Urodela – salamanders,
mudpuppies, newts
– Anura – frogs, toads
– Apoda – caecilians
• Recent evidence places the
lungfishes as ancestors
• 2 hypotheses describe
possible evolutionary
stragies
– Pond to pond
– Food on land
• Anatomy
–
–
–
–
–
–
Tongue  catch food
Larynx  calls
Vomerine vs maxillary teeth
Tympanic membrane
Nictating membrane
Skin  respiratory, mucous
glands
– 3 chamber heart
– Ectothermic  temp. drops 
torpor
– External fertilization
salamander
mudpuppy
siren
Class Reptilia
•
•
•
•
•
Adaptations?
Tough body coverings
Claws on toes
Well developed lungs
Partial division of
ventricle
• Ectothermic
• Internal fertilization
• Amniote egg
• Approx. extant 6,000
sp.
• Once there were 16
orders, today only 4
• Most live in tropics
• U.S. has 275 sp.
Classification
•
•
•
•
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
– Orders:
•
•
•
•
Crocodilia
Sphenodontia
Squamata
Testudines
Squamata
• Includes reptiles with
tough epidermal
scales
• Snakes and lizards
• 5,640 species
• 2 venomous lizards
– Gila monster
(S.W.desert)
– Mexican Beaded lizard
Rhynchocephalia
http://www.kcc.org.nz/animals/tuatara.asp
• Ex. Tuatara
(spiny crest)
• Only 2 extant endangered species
left
• Inhabits 20 small islands off coast
of New Zealand
• Grows up to 60 cm
• Hasn’t changed its form in 225 my
“living fossil”
• All other close relatives died 60
my ago
• Has a 3rd eye on top of head
(absorbs U.V. radiation for Vit. D
prod.), no penis, no visible ear
openings
• Lifespan is about 35 years, very
slow reproductive cycle
Crocodilia
http://www.pbs.org/wgbh/nova/crocs/clickable/
• Large reptiles with
elongated skulls
• Includes alligators
and crocodiles
• 4 chambered hearts
• Valve in back of
mouth prevents water
from entering air
passageway
• Haven’t changed
much in 248 my.;
Survived the
Mesozoic Extinction
Origin and Evolution of Aves
• Archaeopteryx
– The link between reptiles and birds
Characteristics of Birds
• Feathers
Characteristics of Birds
• Bones thin and hollow
Characteristics of Birds
• 4 chambered heart
Bird Heart
A Chicken's
Heart
Bird Heart
Human Heart
A Human's Heart
Characteristics of
Birds
• Furculum
– Fused collar bone
aiding
in flight
– Keeled sternum
Digestive and Excretory
Systems
• Crop and Gizzard
Respiratory System
• Highly efficient to
meet demands of the
high metabolic rate
Brain
• Large
• Good
color
vision
• Good
hearing
Reproductive Systems
• Female has only one ovary
• Males
– testes→sperm→vas deferens→cloaca
Viviparous
Mammary glands secrete milk
Highly
developed
brain
Monotremata
• Lays eggs
Lays eggs
Marsupialia
Pouched mammals
Insectivora
• Shrews
• No teeth; reduced
eyes
Rodentia
Front incisors
continuously grow
Lagomorpha
2 rows of upper incisors that continually grow
No teeth
insectivore
Edentata
Flight
echolocation
Chiroptera
Cetacae
Blowhole, toothed whales
Sirenia
Manatees
Aquatic herbivores
Order Carnivora
Carnivores, long canine teeth
• Dogs, cats, raccoons,
bears, otters
Order
Pinnipedia
Water dwelling carnivores
• Walruses, seal lions,
seals
Artiodactyla
Even toed (cloven hooves)
• Pigs, deer, cow,
sheep
Order
Perissodactyla
Odd toed
• Horse, zebra, rhino
Order Proboscidea
Boneless trunk
• Elephants and wooly
mammoths
Order
Primate
Omnivores
Opposable thumbs
• Monkey, ape, humans,
orangutans, chimps,
baboons