Mammals Kingdom Animalia ---Phylum Chordata Subphylum Vertebrata Class Mammalia What do you get when you cross an elephant with a fish? swimming trunks

Characteristics 1. Hair (some marine mammals have very little) 2. Specialized Teeth 3. Endothermic (warm-blooded) 4. Mammary Glands 5. 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

First Mammal? New fossils suggest that a shrew-like animal that snagged insects from ferns lining the shores of freshwater lakes 160 million years ago, might be one of the first "true" mammals to walk the Earth, back when the dinosaurs roamed. middle Jurassic, around 165 million years ago

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 diet Predators have large canines Herbivores 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 (separation of blood flow references two distinct and separate systems). What other animals have a double loop? (amphibians, birds)

Movement Mammals 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) 2. 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.