Phylum Chordata

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

MammalHeart

What vertebrates do

not have bones?

AgnathaClass 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

OsteichthyesClass Actinopterygii

Class Actinistia

Class Dipnoi

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

siren

mudpuppysalamander

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

SquamataSquamata• Includes reptiles with

tough epidermal scales

• Snakes and lizards• 5,640 species• 2 venomous lizards

– Gila monster (S.W.desert)

– Mexican Beaded lizard

Rhynchocephalia• 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

http://www.kcc.org.nz/animals/tuatara.asp

Crocodilia• 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

http://www.pbs.org/wgbh/nova/crocs/clickable/

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

A Chicken's Heart A Human's Heart Bird Heart

Bird Heart Human 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 eggsLays eggs

MarsupialiaPouched mammals

Insectivora• Shrews• No teeth; reduced

eyes

RodentiaFront incisors continuously grow

Lagomorpha

2 rows of upper incisors that continually grow

EdentataNo teethinsectivore

ChiropteraFlightecholocation

CetacaeBlowhole, toothed whales

SireniaManateesAquatic herbivores

Order Carnivora

• Dogs, cats, raccoons, bears, otters

Carnivores, long canine teeth

Order Pinnipedia

• Walruses, seal lions, seals

Water dwelling carnivores

Artiodactyla

• Pigs, deer, cow, sheep

Even toed (cloven hooves)

Order Perissodactyla• Horse, zebra, rhino

Odd toed

Order Proboscidea

• Elephants and wooly mammoths

Boneless trunk

Order Primate

• Monkey, ape, humans, orangutans, chimps, baboons

OmnivoresOpposable thumbs