1. Class: Mammalia

2. All mammals :
Mammary glands
Hair
A middle ear with 3 bones
A jaw that lets them chew food

3. 3 Main groups: 2. Marsupials – Monotremes – Mammals that lay eggs
Give birth to immature,
underdeveloped live young.
Grow to maturity inside
a pouch called the marsupium
Monotremes –
Mammals that lay eggs
Example: Platypus

4. Only marsupial in the USA
Opossum babies in pouch

5. 3. Eutherian mammals – Give live birth to live
young that have completed fetal development.

6. Body temperature control:
Endotherms
Hair, subcutaneous fat (under the skin) help
to conserve body fat.
Many have sweat glands that help to cool the
body during warm periods. Mammals without
sweat glands will pant to get rid of excess heat.
(Example of homeostasis)

7. High metabolic rate – must eat about 10x
Feeding:
High metabolic rate – must eat about 10x
the amount of food as a reptile of the same
size to maintain homeostasis.
Specialized teeth and jaws to eat different diets.
Herbivore
Carnivore
Cutting, gnawing, grooming
Piercing, cutting,
Tearing.
Works like blades
of scissors to crush and grind food
Flattened for grinding tough plants

8. Carnivores have a shorter digestive tract than
herbivores.
Cows have a rumen where food is stored and
processed.

9. The teeth of whales have been replaced by
stiffened plates called baleen.
These strain out plankton from the water it
takes in.

10. Respiration:
Use lungs
Circulation:
4 Chambered heart

11. Excretion:
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 smell
Ears – 3 small bones in the middle ear.
Well developed eyes –
many have color-sensing
Structures in their eyes.

12. Movement:
Many adaptations of limb bones and muscles to allow mammals to run, walk, climb, burrow, hop, pounce, swing, fly, leap, swim.

13. Reproduction:
Internal fertilization
Monotremes lay eggs outside the female’s body
and nourishes that young with milk from mammary
glands.
Marsupials – give live birth to immature young,
develop further in pouch and drink milk from mother.
Eutherian mammals – have placenta. Get nutrients
and oxygen from mother, give off wastes during
development
Have varied gestation periods (mouse = few weeks,
Elephants = 22 months!)
Parental care of young (varies among different species)