Phylum ChordataBasic Chordate CharactersA Simple Chordate (Amphioxus)compare Hickman p. 273-274From Lampreys to SharksLamprey AnatomyShark Advances over LampreysEvolution of JawsCampbell Fig. 18.17BChondrichthyes ExamplesExternal AnatomyHickman Fig. 15-7Bony FishesAdvanced FeaturesExternal AnatomyAmphibiansAmphibiansAdult Terrestrial featuresAmphibian groupsSalamandersFrogs and ToadsTurtles, Snakes, Lizards, and CrocodilesReptilian adaptationsReptile groupsLizardsExamples of LizardsStart hereSnakesExamples of Snakescompare Campbell Fig. 18.20CrocodilesCrocodile CharacteristicsCrocodiliaTurtlesTurtlesBirdsFeathersFlight MusclesAir Sacs and BreathingMammalsMammal AdaptationsEndothermyHairMammalian Skin GlandsMammalian TeethOviparous MammalsMarsupial MammalsMarsupial MammalsCampbell Fig. 18.22BPlacental MammalsPlacental mammalsPhylum ChordataBasic Chordate Characters• notochord• dorsal hollow nerve cord• postanal tail • segmental muscles • pharyngeal slits and bars(ventral heart)A Simple Chordate (Amphioxus)compare Hickman p. 273-274From Lampreys to SharksmakoLamprey AnatomyShark Advances over Lampreys•jaws– from pharyngeal arches•bony skin plates– evolved to fish scales and teeth• pectoral and pelvic arches and finsEvolution of JawsCampbell Fig. 18.17Bpharyngeal bars or archesflex pointsChondrichthyes Examplesblack-tip reef sharkmanta rayblue-spotted sting rayExternal AnatomyHickman Fig. 15-7Bony FishesIntroduction to Basic FeaturesAdvanced Features•swim bladder– enabling bony skeleton, variable body forms• operculum– to force water over gills• fin skeletal support– for increased maneuverability• terminal, complex mouthExternal Anatomyoperculumlateral linehomocercal tailpectoral finpelvic finterminal mouthAmphibiansEvolution of TetrapodsAmphibians• “living a double life”Have aquatic and terrestrial adaptations•Eggs – fertilized in water, no shell, covered with gelatin• Aquatic larva– Tail, lateral line, gills, no legsAdult Terrestrial features•After “metamorphosis”• Lungs replace gills• Tail disappears•Four limbs•Eardrums• Loses lateral line• Eats insectsAmphibian groups• Have tails– Salamanders, newts, etc.• Lack tailsFrogs and toadsSalamanders Tail! walking is awkward;legs out on sides of bodyFrogs and ToadsTail lost!ribs and neck reduced, hind legs enlarged•communicate with soundReptilesTurtles, Snakes, Lizards, and Crocodilesnostrilpit organpoison glandglottishollow fangReptilian adaptations• Keratin covered scales “waterproofed”• Eggs with shells that retain water– Amniotic egg• Ectothermic - do not use metabolism to alter body temperatureReptile groups• Lizards• Turtles• Crocidiles and alligators• SnakesLizards• skin shed in patches, external ears, usually with legs• well adapted for desert, but also in wet, warm habitats; one iguana is semi-marineExamples of LizardsKomodo dragoniguanaStart hereSnakes• body elongated, legs lost, jaws detach, anterior glottis• move by scales and writhing• all carnivorous, but many are not poisonous• wet or dry terrestrial, freshwater, and fully marine habitatsExamples of Snakescompare Campbell Fig. 18.20garter snakecoral snaketimber rattlesnakeolive sea snakeCrocodiles• alligator, crocodiles, caimans, gavials• freshwater or marine• occupy all temperate and tropical climates except EuropeCrocodile Characteristics• carnivores, foraging partly on land– elevated eyes and nostrils – large, socketed teeth, powerful jaws• tail compressed laterally for swimming• scales not shedCrocodiliaAmerican crocodilenot an alligator:narrow snout, large lower tooth exposed with mouth closedTurtlesshell: dorsal carapace, ventral plastron• very long lifespans• freshwater, marine, & terrestrial• omnivores or carnivoresTurtlesterrestrialfreshwaterplastroncarapacemarineBirds• Amniotic eggs, scales on legs, keratin• Feathers• Reduced skeleton and large muscles for flying• Special lungs and circulatory system• Endothermic – make their own heatFeathers• light weight, but strong– tubular, air-filled• molted and replaced periodically• insulation ,water-proofing, signaling, camouflage, touch sensitivityFlight MusclesWhite meatAir Sacs and BreathingMammalsBasic Features of the ClassMammal Adaptations• endothermy, hair, sweat and scent glands• varying teeth (“heterodont”), epiglottis• improved olfaction, larger nasal cavity• 4-chambered heart, diaphragm• more coordination, acute senses, and learning abilityEndothermymaintaining constant body temperature by using extra energy• insulation by fat, hair, large body size• cooling by sweat, heat radiation, panting• allows activity at low temperaturesHair• manufactured by epidermis•for insulation• for signaling and camouflage• for sensing touch and air motion – especially whiskersMammalian Skin Glands• sebaceous glands– condition, waterproof skin and fur• sweat glands– cooling; communication by odor• mammary glands– milk for offspringMammalian TeethHeterodont- a standard four tooth types:– Incisors– Canines– Premolars– MolarsOviparous Mammals• 3 species in one order Monotremata– all live in Australia or New Guinea• lay eggs, but have hair and nurse youngduck-billed platypus mother, nursingCampbell Fig. 18.22 (a)Marsupial Mammals• fetuses do not fully implant in the simpler uterus• adult females have a belly pouch (marsupium) – newborns stay inside, attached to nipple, for monthsMarsupial MammalsCampbell Fig. 18.22BSouth American tree opossumNorth American opossumAustralian kangarooPlacental Mammals• true placenta formed by fetus and mother• Joins the embryo to the mother within the mother’s uterus• Embryo is nurtured by blood from the mother• 95% of all mammalsPlacental