Mammals

Classification Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrates Class: Mammalia Very diverse class Live on every continent & in every ocean 3 subclasses: Monotremes Marsupials Placental mammals 19 different orders 4400 Species

Key Mammalian Characteristics 1. Endothermic: Warm-blooded Can live in any climate Regulate internal temperature VERY ACTIVE Able to perform strenuous activities for long periods of time. High metabolisms Require a lot of food

Use hair/fur and a layer of subcutaneous fat to conserve heat/ prevent heat lose.

Uses sweat glands, panting, or shedding to cool down their bodies. Recipe for sweat: Excess heat, water and salt.

2. Hair/Fur Lanugo Marine mammals have a small amount of hair. Insulation Camouflage Protection Waterproofing Marine mammals have a small amount of hair. Lanugo

Some animals use it to attract mates:

3. Completely divided 4 chambered heart. Has a complete septum Very efficient heart b/c clean & dirty blood never mix

Milk production - presence of mammary glands - which are modified sweat glands used by the female to feed young Known as teats (provide milk from mammary glands)

Milk production Milk contains: Protein Sugars Vitamins Fat Calcium (sm. amt.) Water

5.Single Jawbone -the lower jawbone in a mammal is single bone whereas in other vertebrates the lower jaw is made up of 2 or more bones.

6. Specialized Teeth Teeth in mammals are modified for different functions Back teeth in general are for: chewing, grinding, crushing, slicing Molars: grind, crush, or cut food Pre-molars: shear, shred or grind food

Teeth are the 1st place physical digestion occurs. Front Teeth: in general are used for biting, cutting, seizing prey Canines: grip & puncture prey Incisors: used to cut Teeth are the 1st place physical digestion occurs.

Teeth and Skull Did you know that bone is 5X stronger than steel?

Using teeth to identify: The number, type and size of the teeth vary according to the specific type of mammal and what it eats.

History of Mammals -Mammals first appeared on Earth at the same time as dinosaurs. -Dinosaurs and mammals competed for food -Dinosaurs were larger and thus more successful at finding food so dinosaurs were much larger in size.

-mammals where only the size of a small rodents. -once dinosaurs went extinct the mammals flourished and grew larger in size and are now the most prominent organisms on Earth.

Three main groups of Mammals Monotremes Marsupials Placentals Which are we????????????????

Monotremes Oviparity Live in New Guinea and Australia Examples: Egg layers lay 1-2 leathery eggs per year feeds off yolk of egg mammary glands Live in New Guinea and Australia Examples: Duckbill platypus Spiny anteater

Marsupials 280 species of marsupials/pouched mammals Viviparity Ex. Opossum (live in US), kangaroo, koala Viviparity Give birth to live young Develop in uterus(sm period of time) Under-developed young crawl out of vagina into pouch where they feed off teats

Placental 19 orders of placental animals Viviparity Give birth to live young-uterus, placenta, umbilical cord (provides nourishment to fetus from mother) Gestation period (time it takes for full fetal development) varies with different placentals. Cared for by parents Fed w/ mammary glands until old enough to feed on own

Gestation Periods 40 weeks 92 weeks 15 weeks 4 weeks 71 weeks 36 weeks