1. Mammals

2. Characteristics of Mammals
3 Middle Ear Bones – malleus, incus, and stapes (hammer, anvil, and stirrup) the first two derived from the ancestral jaw.
Hair – composed of keratin for insulation, sensation, appearance, and protection. (other keratinized structures – horns, antlers,
Mammary Glands – modified sweat glands that, in females, produce milk to nourish their offspring.

3. Other important characteristics include highly differentiated teeth, 2 sets of teeth, single lower jaw bone, 4 chambered heart, secondary palate, muscular diaphragm, highly developed brain, endothermy and homeothermy, separate sexes (XX or XY), and internal fertilization.

4. Mammalian Teeth Heterodont teeth – different types of teeth
2 Sets of teeth - Diphyodont
Dental Formula
Diastema
Carnassial apparatus
Incisors chisel shaped for gnawing and nipping (1 root)
Canines long conical for catching, killing, and tearing (1 root)
Premolars and Molars broad for chewing (1-2 or 2-3 roots)

5. Mammalian Glands
Glands are an epidermal tissue that secrete substances.
Sebaceous – secrete oil for waterproofing.
Sudoriferous – sweat for evaporative cooling and elimination of waste.
Scent – secrete pheromones for defense, sex recognition, and territorial behavior.

6. Mammalian Classification
Prototheria (Monotremes) - are oviparous (Egg-laying).
Metatheria (Marsupials) – are viviporous with a short gestation, further development occurring in a pouch. Doubled reproductive features in females & males.
Eutheria (Placentals) – are viviparous with a long gestation.

7. Terrestrial Placental Orders
Order Artiodactyla
Order Carnivora
Order Insectivora
Order Lagomorpha
Order Perissodactyla
Order Rodentia
Order Chiroptera
Order Primates
Order Edentata (Xenartha)
Order Proboscidea

8. Order Artiodactyla (Even Toed Ungulates) st
Ungulates walk on their toes.
Most are specialized for cursorial locomotion with long hoofed legs, and have diversified as the Perssodactyls have declined.
Number of teeth is variable but they have a diastema.
Males often sport antlers or horns.
Deer, Sheep, Javelina, Antelope, Cows, Hippopotamuses, Camels, Giraffes

9. Order Carnivora st
Although not all current carnivora are carnivorous, the ancestors were meat eaters.
Recognizable carnassial apparatus for shearing meat and tendons (between the 4th upper premolar and 1st lower molar), keen senses, and large brain.
3 upper and 3 lower incisors.
Dogs, Cats, Bears, Raccoons,

10. Order Insectivora
Third largest order of mammals and possibly the most primitive group (mesozoic mammals are rather shrew-like).
Moles and Shrews

11. Order Lagomorpha st Resemble large rodents with short tails.
Flaps of skin can close behind the incisors and close the nostrils.
2 upper incisors, one behind the other.
(2/1, 0/0, … 4/4)
Fenestrated skull
Rabbits

12. Order Perissodactyla (Odd Toed Ungulates)
Horses, Rhinoceroses, Zebras

13. Feeding Adaptations
Herbivorous mammals have special adaptations for digesting cellulose.
Perissodactyls, lagomorphs, and rodents have a cecum or fermentation pouch between the small and large intestine. In lagomorphs droppings are re-eaten.
Artiodactyla are ruminants with the first three chambers of their stomach are storage and fermentation chambers. Food is regurgitated and chewed.

14. Order Rodentia st Largest order of mammals (40% of mammal species).
Individual upper and lower incisors that are rootless and grow throughout life for a gnawing life style.
(2/1, 0/0, 3/2, 2-3/3)
Squirrels, Chipmunks, Rats, Mice, Beavers, and Porcupines

15. Being Warmblooded Endothermy – the generation of internal heat
Homeothermy – the maintenance of constant temperature

16. Cold Weather Adaptations
Winter Sleep – the organism is less active, alert, and easily aroused (Bears and raccoons).
Hibernation – the organism slows metabolism, and heart and respiratory rates (monotremes, and some insectivora, rodentia, and chiroptera).

17. Order Chiroptera
Second largest order of mammals.
Bats

18. Order Primates
Lemurs, Tarsiers, Monkeys, Gibbons, and Apes

19. Order Edentata
Incisors and canines absent.
Armadillos

20. Didelphimorpha
American marsupials

21. Order Proboscidea
Elephants

22. Aquatic Placental Orders
Order Carnivora – Otters, Weasels, Seals, Walruses, Sea Lions
Order Cetacea – Whales, Dolphins, Porpoises
Order Sirenia - Manatees