Mammals

Classification• Kingdom:

– Animalia• Phylum:

– Chordata• Subphylum:

– Vertebrates• Class:

– Mammalia3 subclasses: Monotremes Marsupials Placental mammals 19 different orders 4400 Species

Very diverse classLive on every continent & in every ocean

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.

2. Hair/Fur– Insulation– Camouflage– Protection– Waterproofing

Marine mammals have a small amount of hair.

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

4.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

• Back teeth in general are for: chewing, grinding, crushing, slicing

• Molars: grind, crush, or cut food

• Pre-molars: shear, shred or grind food

Teeth in mammals are modified for different functions

• 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

1.Monotremes2.Marsupials3.Placentals

Which are we????????????????

Monotremes• Oviparity

– 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– 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