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

Osteichthyes Class 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 mudpuppy salamander

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 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 3 rd 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 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 A Chicken's HeartA Human's 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 eggs

Marsupialia Pouched mammals

Insectivora Shrews No teeth; reduced eyes

Rodentia Front incisors continuously grow

Lagomorpha 2 rows of upper incisors that continually grow

Edentata No teeth insectivore

Chiroptera Flight echolocation

Cetacae Blowhole, toothed whales

Sirenia Manatees Aquatic 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 Omnivores Opposable thumbs