Biology: Mammals

Hair

- all mammals have some sort of hair - all mammals have hair instead of scales or feathers

Teeth

- almost all mammals have teeth - fish/reptiles have teeth used for holding/tearing prey - mammals have different types of teeth - molars: grinding/slicing food - incisors: puncture/tear flesh of prey - a beaver's front teeth (that they use for gnawing wood) never stop growing.

The Monotremes

- duck-billed platypus and two different species of the spiny anteater - make milk and have hair and teeth - a monotreme is a mammal that reproduces by laying eggs

Milk

- female mammals make milk in their mammary glands to feed their young - this milk nourishes their young with the nutrition they need until they can develop to eat other types of food

The following are traits all mammals share:

- hair - cool-down ability - diaphragm - teeth - milk - intelligence

Placental Mammals

- have a gestation period inside mother's uterus - the uterus: specific for the growing of offspring - the placenta: organ that develops during mammal's pregnancy; purpose: to feed the growing embryo, pass along oxygen, and remove waste - 95% of all mammals are placental mammals

Marsupials

- kangaroos, wombats, koala bears - 70% of marsupial species are found in oceania - the rest are found in the americas, with one, the opossum, found in the united states - very short period of development inside their mother's body and followed by a second period of development inside a special pouch of the mother that is made of skin and hair

Cool-down Ability

- mammals are endotherms - mammals keep a constant body temp, helping the complex organ systems running smoothly - in order to do this, mammals can cool down - humans, have sweat glands - sweat glands allow water to leave the body - done through evaporation; exerts a cooling-down effect bc the heat in the body leaves through the water and dissipates into the air

Diaphragm

- mammals have a diaphragm - swells and shrinks with air as they breathe in and out - mammals need a large amount of oxygen to run all the processes in their bodies

Internal Fertilization

- mammals utilize internal fertilization - majority of mammals develop inside mother's uterus - these are called placental mammals - classified by how they develop before birth

Intelligence

- mammals, especially primates, are very intelligent - mammals have this intelligence thanks to our large brains and complex nervous systems

The three classes of mammals are:

- marsupials - monotremes - placental

Mammals

- success is due to nurture/care for their young - this protection of the young while they develop and learn behaviors by observing their parents separates mammals from all the other animals - mammals are the most advanced animals - 5,500 species of mammals

Carnivora

Carnivores are meat eaters. This order includes cats, dogs, and bears. Some carnivores, such as bears, eat plants as well.

Insectivora

Insectivores eat insects. This is about the only characteristics mammals in this order share.

Primates

Primates include monkeys, gorillas, chimpanzees, orangutans, and humans.

Sirenia

Sea cows and manatees make up this order. They live in the sea like dolphins and whales but are more closely related to elephants

Edentata

The only animals in this order are the giant anteater, tree sloths, and armadillos. These mammals do not have teeth.

Lagomorpha

These animals are the bounding, bouncing mammals and include rabbits, hares, and pikas. They are able to bound because the bones in their hind legs have been fused together.

Chiroptera

These are bats and only bats. Bats are the only mammals that can fly.

Artiodacytla

These are the even-toed hoofed animals and include hippos.

Perissodactyla

These are the hoofed animals with odd numbers of toes and include horses, cows, pigs, and camels.

Rodentia

This order includes rats, mice, hamsters, ferrets, beavers, squirrels, and chipmunks. They are the most numerous order of mammals. Rodents' teeth continuously grow and are razor sharp.

Pinnipedia

This order includes seals, sea lions, and walruses. The majority are found in cold-water environments.

Proboscidea

This order includes the elephants. Their tusks are modified incisor teeth, and they have long, flexible trunks.

Cetacea

This order includes the whales, dolphins, and porpoises. They breathe through blow holes and have verylittle hair.