Reptiles

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Reptiles. Class Reptilia Snakes, lizards, turtles, tortoises, crocodiles, alligators Amniotic egg…leathery shell protects water environment inside Dry, scaly skin prevents water loss. Reptiles. Circulation (2 closed systems … pulmonary and systemic) - PowerPoint PPT Presentation

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Reptiles• Class Reptilia• Snakes, lizards, turtles, tortoises,

crocodiles, alligators• Amniotic egg…leathery shell

protects water environment inside

• Dry, scaly skin prevents water loss

Reptiles• Circulation (2 closed systems …

pulmonary and systemic)– Heart 3 chambers in snakes and

turtles (septum divides ventricles and

minimizes blood mixing)– Heart 4 chambers in crocodiles

Reptiles• Respiration… lungs divided into

lobes…many small sacs (alveoli) greater surface area for

respiration.• Brain very well developed,

especially cerebrum (front area, controls movement)

Reptiles• Thermoregulation

– Ectothermic…absorb heat from surrounding, so body

temp. is close to surroundings (used to be called cold blooded)•Amphibians and fish are ectotherms,

too.

Reptiles• Reproduction:

– Most oviparous…lay eggs that develop on their own

– Some ovoviviparous…keep egg in body to develop and lay

close to time of birth– Few viviparous…live birth

Reptiles• Class: Chelonia:

– Turtles and tortoises• Class Squamata:

– Lizards and snakes• Class Rynchocephalia:

– Tuatara• Class Crocodilia

– Crocodiles, alligators, caimans

Class Squamata:Lizards and snakes

Birds• Class Aves• Evolved about 150 million years ago• Forelimbs modified to wings• Lightweight skeleton (hollow/fused bones)• Closed circulatory system with 4

chambered heart…no mixing of oxygenated/deoxygenated blood…higher

metabolism/movement• Large, well developed brain

Birds• Endothermic (temp 104 – 106 oF)• Lungs and air sacs• Oviparous (lay eggs)• Feathers (and skin) cover body

– Flight, down, contour feathers• Digestive organs include: crop, 2

stomachs (#2…gizzard has stones in it)

Order ColumbiformesPigeons, doves

Order CiconiiformesHerons, storks, ibises,

egrets, penguins

Mammals• Class Mammalia• Evolved 300 million years ago• Hair (and skin) body covering• Endothermic• 4 chambered heart (closed

circulatory system)• Females produce milk for young

Mammals• Specialized teeth for different jobs• Lungs with alveoli (small sacs like

reptiles)•Diaphragm (muscle below

ribcage) helps breathe• Brain about 15 times heavier

than same sized fish, amphibian or reptile!

Mammals• 3 groups of mammals

– Monotremes: Oviparous (lay eggs), e.g. duck-billed platypus

– Marsupials: viviparous (young born immature, develop inside mother for some time), e.g.

opposum, kangaroo– Placental: viviparous (young fed in

uterus by placenta), most mammals you think of

Order Xenarthra• Anteaters,

armadillos, sloths• 30 spp

Order Lagomorpha• Rabbits, hares,

pika• 70 spp

Order Rodentia• Mice, squirrels,

chipmunks, rats• Largest Order,

over 1800 spp

Order Primata• Monkeys,

gibbons, apes, humans

• 235 spp

Order Chiroptera• Bats• 900 spp

Order Insectivora• Shrew,

hedgehogs, moles

• 390 spp

Order Carnivora• Dogs, cats, bears,

sea lions, otters, seals, hyenas

• 274 spp

Order Artiodactyla• Deer, cattle, giraffe,

pig, camel• Even # toes on hoof• 210 spp

Order Perissodactyla• odd # toes on hoof• Horse, rhino, zebra• 17 spp

Order Cetacea• Whale, dolphin,

porpoise• 90 spp

Order Sirenia• Manatee,

duogong• 4 spp

Order Proboscidea• African and Asian

elephants• 2 spp

Order Montremata• Lay eggs• Platypus,

echidna• 3 spp

Order Marsupiala• Have pouches• 280 spp• Opposum,

kangaroo, koala bear