1. Mammals

2. Subphylum: Vertebrata
Mammalia
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class Mammalia

3. Class Mammalia Major Characteristics
Endothermy
Hair
Completely divided, 4-chambered heart
Milk
Single jawbone
Specialized teeth
Amniotes
3 inner ear bones

4. Key characteristics
Endothermy-Mammals produce body heat internally through metabolism.
Hair- All mammals have hair. The main function of hair is to insulate the body against heat loss.
Completely Divided Heart- Mammals have a four chambered heart with two completely separate ventricles.

5. Key Characteristics Cont.
Milk- Female mammals produce milk from their mammary glands. They do this to feed their offspring.
Single Jawbone- This helps identify mammalian fossils. (Reptiles have several jawbones.)
Specialized Teeth-Front teeth are used for biting, cutting, or seizing prey. Side teeth are for crushing, grinding, or slicing.

6. Amniotic
Eggs developed with a set of membranes (placenta) to protect them in a terrestrial environment
they prevent dessication, in other words, they ensure that the embryos do not dry-out
they enable gas exchange between the embryo and its environment as its develops
they allow waste materials to be disposed of while the embryo develops
they enable the embryo to receives the nutrition it needs to develop

7. 5,000 species
26 orders
Mammal’s

8. Groups Order Monatremata: duckbill platypuses, spiny anteaters
Order Marsupialia: opossums, kangaroos, koalas, wallabies
Placental mammals (18 orders)

9. Order Monetremata In this order the animal lays eggs
They include many of the mammals that people consider as abstract or weird.
Only three species exist in this order.
The species only live in Australia and New Guinea.

10. Order Marsupialia 280 species exsist within this order.
Australia, New Guinea, & The Americas is where these animals populate.
The incubation period for these animals is very short so many babies are born underdeveloped in a shorter period of time, e g. kangaroo joeys are born after a 4-5 week gestation.

11. Placental Mammals 95 percent of mammals are placental mammals.
There are 18 different orders within the group of placental mammals.
The incubation period of these animals is longer than that of the marsupials

12. Placental mammals
Primates: Monkeys, Lemurs, Gibbons, Orangutans, Gorillas, Chimpanzees, Humans
Insectivora: Moles and Shrew
Chiroptera: Bats
Enentata: Armadillos, Sloth, Anteaters
Pholidota: Pangolins
Rodentia: Squirrels, Woodchucks, Mice Rats, Muskrats, Beavers
Lagomorpha: Rabbits, Hares, Pikas
Carnivora: Whales, Porpoises, Dolphins
Sirenia: Sea Cows, Dugongs, Manatees
Proboscidea: Elephants
Pinnipedia: Seals, Sea Lion, Walruses
Perissodactyla: Rhino’s, Horses, Zebras
Artiodactyls: Hippos, Camels, Deer, Giraffes, Cattle, Sheep, Goats
Macroscelidea: Elephant Shrew
Scandentia: Tree shrew
Hyracoidea: Hyraxes
Dermoptera: Flying lemurs
Tubulidentata: Aardvark

13. Trophic categories
Scientists place placental mammals in 4 trophic categories based on what they eat:
Instectivore
Eat insects and other small invertebrates
Moles, shrews, anteaters
Herbivores
Eat vegetation (primary consumers)
Rabbits, deer, horses
Carnivores
Feed on herbivores (secondary/tertiary consumers)
Wolves, lynx
Omnivores
Feed on both plants and animals
Raccoons, primates

14. What is this?

15. Evolutionary history:Synapsids
“mammal-like reptiles”
Diverged from a common ancestor with reptiles
Have a very distinct skull with a hole in the jaw for attachment of muscles of the jaw

16. Reproduction
Monotreme mothers typically one or two eggs and incubates them with her body heat.
Newborn marsupials emerge form their mothers uterus when they are ready. Its growth and development continues in its mothers pouch.
Placental mammals: Once the egg is fertilized it attaches to its mothers uterus and is nourished by the placenta.

17. Remember, Synapsids gave rise to mammals and mammal-like reptiles, the first of which were the THERASPIDS:

18. Pentadactyl limbs Pentadactyl (pent = 5, dactyl = finger)
Type of adaptive radiation in mammals
The pentadactyl limb has become adapted to different environmental conditions and modes of life

19. Convergent evolution
Structures of unrelated species can evolve to look alike because the structures are adapted to a similar function. These are called analagous structures
They differ from each other in their microscopic details and their embryonic development
The process by which they evolve to resemble each other is called convergent evolution