Mammals

1. Mammals Chapter 32

2. Introduction Ch 32.1

3. What are Mammals? • Class: Mammalia • 2 Key Features • Hair - warmth • Mammary Glands – produce milk for young • Breathe Air • Have 4-chambered hearts • Endotherms: generate and conserve body heat

4. Evolution • Neither hair nor mammary glands are preserved in the fossil record. • Other distinguishing characteristics help identify mammals including: • Lower jaw consisting of a large, teeth-bearing bone connected to the skull by a joint. • Complex teeth that are replaced once in the lifetime. • Distinctive features of the limbs and backbone.

5. Form & Function • Body Temperature Control • Body hair helps mammals retain heat. • Higher metabolic rate helps mammal generate heat. • Fat helps conserve body heat. • Sweat glands help cool the body.

6. Form & Function • Feeding • Due to their high metabolic rate, mammals must eat nearly 10 times as much food as a reptile of the same size. • Include herbivores, omnivores, and carnivores. • Jaws and teeth are adapted to eat foods other than insects. • Have specialized teeth allowing food to be processed efficiently to obtain more energy.

7. Form & Function • Feeding

8. Form & Function • Respiration • All mammals use lungs to breathe. • Blood is oxygenated in the lungs. • Breathing controlled by muscles and diaphragm that increase and decrease the volume of the lungs.

9. Form & Function • Circulation • 4-chambered heart • Right side of heart receive oxygen-poor blood (high in CO2) and then pumps it to the lungs. • After picking up oxygen in the lungs, blood enters the left side of the heart and then gets pumped out to the body.

10. Form & Function • Response • 3 Main Parts to the Brain: • Cerebrum – complicated behavior such as thinking • Cerebellum – controls muscular coordination • Medulla oblongata – regulates involuntary functions • Cerebrum contains an area called the cerebral cortex which is the center of thinking and other complex behavior. • Olfactory bulb – sense of smell. • Color vision most important to diurnal animals (active during daylight).

11. Form & Function • Chemical Controls • Endocrine glands to regulate body activities. • Release chemicals called hormones. • Fighting Disease • Immune system protects animals from disease.

12. Form & Function • Movement • Evolved a variety of adaptations aiding in movement. • Backbone that flexes both vertically and side to side. • Shoulder and pelvic girdles that are streamlined and flexible allowing limbs to move in a variety of ways.

13. Form & Function • Reproduction • Mammals give birth in 3 ways: • Placental mammals give birth to live young • Monotremes lay eggs • Marsupials bear live young that live in an external pouch

14. Diversity Ch 32.2

15. Diversity • Class Mammalia contains about 4500 different species. • There are 19 different orders of mammals. • Mammals are divided into 3 groups based on their means of reproduction and development. • 3 Major Groups of Living Mammals: • Monotremes • Marsupials • Placentals

16. MonoTremes • Monotremes are egg-laying mammals. • They share 2 characteristics with reptiles. • 1) Reproductive, Urinary, and Digestive Systems all open into the cloaca. • 2) They lay soft-shelled eggs that are incubated outside of the body. • They differ from reptiles in the fact that the young obtain nourishment from their mother’s milk. • There are only 3 species that exist today. • Duckbill Platypus • 2 Species of Spiny Anteaters or Echidnas

17. MonoTremes • Echidna • Spines covering the top of the body • Long, sticky tongue to catch ants, worms, and other insects • Found only in Australia and New Guinea • Duckbill Platypus • Tail like a beaver • Body like an otter • Webbed feet and a bill like a bird • Lay eggs • Found in the deciduous forests of Australia

18. Monotremes

19. Marsupials • Marsupials give birth to live young that complete their development in an external pouch. • The embryo is born at a very early stage of development. • Once it is born it crawls across the mother’s fur and attaches to a nipple that is located in a pouch called the marsupium. • The embryo will spend several months inside the mother’s pouch until it can grow large enough to survive on its own.

20. Marsupials • There are 250 species of Marsupials. • They can be found in New Guinea, Australia, Tasmania, and the Americas. • The only marsupial found in North America is the opossum.

21. Marsupials • Marsupials include kangaroos, koalas, and wombats.

22. Placental Mammals • Placental mammals get their name from an internal structure called the placenta. • This is formed when the embryo’s tissues join with tissues from the mother’s body. • Allows for efficient exchange of nutrients, oxygen, carbon dioxide, and wastes between the mother and embryo.

23. Placental Mammals • The embryo develops for a much longer time inside the mother. • Mice: a few weeks • Dogs: 2 months • Humans: 9 months • Elephants: 2 years • After birth, most placental mammals care for their young and provide them with nourishment by nursing.

24. Embryology

25. Placental Mammals • Order: Insectivora • Have long, narrow snouts • Sharp claws for digging • Insect eaters • Examples: Shrews, Hedgehogs, and Moles

26. Placental Mammals • Order: Rodentia • Single pair of long, curved incisor teeth • Gnaw wood and other plant material • Examples: mice, rats, squirrels, beavers, chipmunks, porcupines, prairie dogs

27. Placental Mammals • Order: Lagomorpha • Herbivores • Have hind legs adapted for leaping • Examples: rabbits, hares

28. Placental Mammals • Order: Xenarthra • Simple or no teeth • Diet consists of insects • Adaptations include long tongue and claws for digging • Examples: sloth, anteaters, armadillos

29. Placental Mammals • Order: Chiroptera • Winged mammals • Diet consists of mostly fruit and insects • Three species feed on the blood of other vertebrates • Examples: Bats

30. Placental Mammals • Order: Cetacea • Adapted to underwater life • Must surface to breathe • Live and breed in the ocean • Examples: humpback whale, narwhal, sperm whale, beluga whale, river dolphins

31. Placental Mammals • Order: Sirenia • Herbivores • Live in rivers, bays, and warm coastal waters • Fully aquatic • Examples: manatees, dugong

32. Placental Mammals • Order: Carnivora • Most animals in this order eat meat • Some eat plants • Stalk or chase prey • Examples: dogs, foxes, bears, raccoons, walruses, cats

33. Placental Mammals • Order: Carnivora • Family: Canidae (dogs, wolves, foxes) • Family: Felidae (cats) • Family: Mephitidae (skunk and stink badger) • Family: Mustelidae (badger, otter, weasel) • Family: Otariidae (seals and sea lions) • Family: Phocidae (earless seals) • Family: Procyonidae (raccoons) • Family: Ursidae (bears)

34. Placental Mammals • Order: Perissodactyl • Hoofed animals with an ODD number of toes • Herbivores • Examples: horses, tapirs, rhinoceroses, zebras

35. Placental Mammals • Order: Artiodactyls • Hoofed mammals with an EVEN number of toes • Large, grazing animals • Examples: cattle, sheep, goats, pigs, giraffe, ibex, hippo, camel, antelope, deer, gazelle

36. Placental Mammals • Order: Probosciedea • Mammals with trunks • Only 2 species survive today • Examples: Asian Elephant, African Elephant

37. Placental Mammals • Order: Primate • Have a highly developed cerebrum and complex behaviors • 200 Species • Examples: lemurs, tarsiers, apes, gibbons, macaques, humans

38. Primates