Mammals evolved from reptiles during the late Jurassic period. The first true mammal was a small, shrew-like organism that lived alongside dinosaurs. Mammals are characterized by hair and mammary glands, and have more developed brains than other animals. There are three main types of mammalian reproduction: monotremes lay eggs, marsupials give birth to tiny embryos that develop further in the mother's pouch, and placentals develop embryos internally and provide milk through mammary glands. The document further describes 14 orders of mammals, including their defining characteristics and examples.

1. evaluation Very good You are corect

2. Mammalia

3. Mammal Evolution Mammals are believed to have evolved from Reptiles during the late Jurassic period

4. Mammal Evolution The first true mammal was a small, shrew-like organism that coexisted with Dinosaurs Ex. Hadrocodium fossil found in Northern China in 2002

5. Mammal Evolution Mammal’s inner-ear bones probably evolved from modified ancestral reptile jaw bones

6. 3 Major Reproductive Categories Monotremes Egg-laying mammals (Ex. Echidna + Platypus)

7. 3 Major Reproductive Categories Marsupials Embryos born very early and nurse from inside mother’s pouch (Ex. Kangaroo, Koala)

8. 3 Major Reproductive Categories Placentals Embryos develop inside the womb, receiving nutrients and O 2 from the mother via the Placenta Newborns fed milk from mammary glands.

9. Mammal Characteristics Characterized by hair and mammary glands Whales have very little hair

10. Mammal Characteristics Mammalian brains are more developed and specialized (cephalized) than any other class of animals

11. Mammal Characteristics All mammals have special sweat glands that are modified for producing milk, called Mammary glands

12. Mammal Characteristics Mammals are Heterodontic Teeth are differentiated Used for biting, grinding, tearing and crushing Ex. Incisors, molars, canines, etc.

13. Mammal Orders There are 19 orders of mammals We will look at the characteristics of 14 of them Order: Monotremata Lay Eggs (Ex. Echidna, Platypus) Order: Marsupiala Young grow in pouch (Ex. Koala)

14. Order: Insectivora Small pointed teeth, adapted mainly for eating insects Ex. Moles, Shrews, Hedgehogs

15. Order: Rodentia Nearly 50% of mammals are rodents Have no canine teeth, but two very larger incisors Almost all are herbivores Ex. Mice, Squirrels, Beavers

16. Order: Edentata Have no teeth Ex. Armadillos, Sloths, Anteaters

17. Order: Carnivora Very diverse group, Meat eaters Canine teeth highly developed Ex. Wolves, Bears, Raccoons, Otters, Skunks, Mongoose, Cats

18. Order: Serenia Aquatic mammals that breathe through their mouth and nose Herbivores Ex. Manatees and Dugongs

19. Order: Chiroptera Forelimbs adapted for flight May find prey by echolocation Ex. Insectivorous Bats, Old World Fruit Bats

20. Order: Lagomorpha Large incisor teeth Hindlimbs larger than forelimbs Ex. Rabbits and Pikas

21. Order: Cetacea Fully aquatic mammals Vestigial pelvic bones Evolved from a wolf/bear-like land mammal

22. Order: Cetacea Highly developed brain Have a dorsal blow-hole Ex. Toothed Whales, Baleen Whales

23. Order: Proboscidea Nose and top lip are highly enlarged into a muscular trunk for grasping items Ex. Elephants

24. Order: Primata Highly developed brains Often bipedal Ex. Lemurs, Monkeys, Apes, Humans

25. Order: Primata Humans are relatively new primates We appear to share a recent common ancestor with chimpanzees

26. Order: Artiodactyla Hooves with even-numbered toes Many of them are ruminants with a 4-chambered stomach Ex. Deer, Giraffe, Cattle, Pig, Camel, Hippo

27. Order: Perissodactyla Have odd-numbered toes Ex. Horses, Tapirs, Rhinoceroses