2. Mammals Chapter 32

3. What’s a mammal? hair mammary glands breathe air and have a diaphragm 4 chamber heart/ double loop circulation endotherms

4. Evolution -first mammals appeared 220 million years ago, very small creatures - stayed small until dinosaurs died out, then underwent a burst of adaptive radiation in Cenozoic era

6. Characteristics Body temp control- allows mammals to move at night and in dark -endotherms -sweat glands for cooling, dogs pant instead, pigs wallow in mud -subcutaneous fat- under skin, insulates -high metabolism to generate internal heat

7. Feeding eats 10 times as much food as a reptile of same size some whales are filter feeders omnivores/carnivores/ herbivores early mammals ate insects stronger jaws to support teeth: molars, premolars, canines, incisors carnivores-short intestines, herbivores- long intestines Cows and their relatives have a stomach chamber called “rumen” that holds symbiotic bacteria that helps with digestion

8. Respiration breathe air using diaphragm and chest muscles/ribs Wake up!!

9. Circulation 4 chamber/ double loop

10. Excretion kidneys- extract nitrogenous waste in the form of urea. Urea and other waste mixed with water to become urine. Urine moves to urinary bladder for storage. Kidneys retain sugars, salts, and other compounds. (urine test)

11. Response -“Most highly developed brains?” -3 parts: cerebrum, cerebellum, medulla oblongata -cerebrum-complicated behaviors such as thinking and learning -cerebellum- muscular coordination -medulla oblongata-involuntary controls such as breathing and heart rate -highly refined senses: bloodhounds’ sense of smell, bats’ hearing, color vision,

12. Movement backbone that flexes in many dimensions shoulder and pelvic girdles run, walk, climb, burrow, hop, pounce, swing, fly, leap, swim, etc.

13. Reproduction internal fertilization Oviparous- “monotremes”- duck bill platypus and 2 species of spiny anteaters Viviparous- 1) “marsupials”- young crawls into pouch before full grown – 2) “placentals”- young develops full term in uterus