2All mammals :Mammary glandsHairA middle ear with 3 bonesA jaw that lets them chew food
33 Main groups: 2. Marsupials – Monotremes – Mammals that lay eggs Give birth to immature,underdeveloped live young.Grow to maturity insidea pouch called the marsupiumMonotremes –Mammals that lay eggsExample: Platypus
4Only marsupial in the USA Opossum babies in pouch
53. Eutherian mammals – Give live birth to live young that have completed fetal development.
6Body temperature control: EndothermsHair, subcutaneous fat (under the skin) helpto conserve body fat.Many have sweat glands that help to cool thebody during warm periods. Mammals withoutsweat glands will pant to get rid of excess heat.(Example of homeostasis)
7High metabolic rate – must eat about 10x Feeding:High metabolic rate – must eat about 10xthe amount of food as a reptile of the samesize to maintain homeostasis.Specialized teeth and jaws to eat different diets.HerbivoreCarnivoreCutting, gnawing, groomingPiercing, cutting,Tearing.Works like bladesof scissors to crush and grind foodFlattened for grinding tough plants
8Carnivores have a shorter digestive tract than herbivores.Cows have a rumen where food is stored andprocessed.
9The teeth of whales have been replaced by stiffened plates called baleen.These strain out plankton from the water ittakes in.
11Excretion:Well developed kidneys that extract nitrogenous wastes from the blood to form urine.Response:Most highly developed brain of any animals.Well developed sense of smellEars – 3 small bones in the middle ear.Well developed eyes –many have color-sensingStructures in their eyes.
12Movement:Many adaptations of limb bones and muscles to allow mammals to run, walk, climb, burrow, hop, pounce, swing, fly, leap, swim.
13Reproduction:Internal fertilizationMonotremes lay eggs outside the female’s bodyand nourishes that young with milk from mammaryglands.Marsupials – give live birth to immature young,develop further in pouch and drink milk from mother.Eutherian mammals – have placenta. Get nutrientsand oxygen from mother, give off wastes duringdevelopmentHave varied gestation periods (mouse = few weeks,Elephants = 22 months!)Parental care of young (varies among different species)