MammalsChapter 32

Kingdom Animalia---Phylum Chordata------Subphylum Vertebrata---------Class Mammalia

Characteristics

1. Hair (some marine mammals have very little)2. Specialized Teeth3. Endothermic (warm-blooded)4. Mammary Glands5. Placenta (most)6. Diaphragm - muscle that aids breathing

Evolution of Mammals

Mammals did not come to dominate until the CENOZOIC ERA, after the dinosaurs became extinct

Early mammals were probably rodent-like and nocturnal

How do mammals stay warm?

Hair insulates most mammals

Some marine mammals have a layer of subcutaneous fat (blubber)

What is the placenta?

Attached to the wall of the uterus , it provides the fetus with nourishment. 

The Birth of a Giraffe

What are mammary glands?

Only found in mammals, produce milk to feed young.

How the Diaphragm Works

Specialized Teeth

• Incisors – biting• Canines - stabbing, holding• molars - crushing, grinding

Different types of mammals have different types of teeth - depending on their dietPredators have large caninesHerbivores have large flat molars

The canines of predators are very large and sharp, used for tearing flesh

Digestion

Mammals have diverse diets. Herbivores often have an extra stomach chamber called a RUMEN to help them digest plants

This chamber holds bacteria that can digest plant material

Circulation

Mammals have a 4 – chambered heart and double loop circulation.

What other animals have a double loop?

MovementMammals are a diverse group. Some…

• Run• Climb• Dig• Fly• Swim

Legs are adapted to a particular job

Reproduction

Most mammals give birth to live young. There are two groups that are exceptions…

1.Monotremes (lay eggs)• Marsupials (develop young in a pouch)

Order Monotremata

• Egg laying mammals found only in Australia

• Have reptilian characteristics (cloaca & egg laying)

• Have mammalian features (hair, mammary gland)

Examples: Duck Billed Platypus and the Echidna (also called a Spiny Anteater)

Order Marsupiala

• Mammals bear their young in am immature state, babies develop in a pouch

• Majority are found on Australia, opossums are found on other continents

Marsupial Examples

Can you name these animals?

Kangaroo Birth

Placental Mammals

• Placental Mammals have a gestation period (length of time in uterus)

• Domesticated animals have been kept and bred by people - cows, dogs, pigs, horses..etc

Very diverse group, you will need to know all of the orders. This topic is on the next presentation.