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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.
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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
Agnatha Class Myxini Class Cephalaspidomorphi
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
Osteichthyes Class Actinopterygii Class Dipnoi Class Actinistia
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 Amphibia“dual life”
salamander mudpuppy siren
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. Class Reptilia
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 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 Human Heart Bird Heart Bird 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
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
Edentata No teeth insectivore
Chiroptera Flight echolocation