1. Mammals

2. What’s a mammal? hair Mammary/milk glands (mamma = nipple)
breathe air and have a diaphragm
Most are Viviparous (except marsupials and monotremes)
4 chamber heart/ double loop circulation
endotherms

3. 3 Groups Placental Marsupial Monotreme About 90% of all mammals
Over 4,000 species
viviparous
Marsupial
Ovoviviparous
About 334 species
Have a pouch to nurse young
Monotreme
Only 5 living species
oviparous

4. Evolution
first mammals appeared 220 million years ago, very small creatures
stayed small until dinosaurs died out, then underwent a burst of evolution and diversity
First mammals were monotremes
Marsupial family came next
Placental is the most recent
Very few monotremes and marsupials still exist – most evolved or died out

8. 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

9. 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

13. Respiration
breathe air using diaphragm and chest muscles/ribs

14. Circulation
4 chamber/ double loop

15. Excretion
kidneys-
extract nitrogenous waste from blood 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)

16. 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

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

20. Reproduction
internal fertilization
3 groups are largely based on this