1. Mammals Bio II Honors Rupp

2. Origin and Evolution  4400 species  More than 20 orders  Found on every continent and every ocean

3. Endothermy  Body heat produced through metabolism  Nearly constant temperature  Regulated through metabolism and surface area

4. Hair  Main function is to insulate against body heat loss  May also act as camouflage

5. Completely divided heart  Four chambered heart with two separate ventricles  Deoxygenated blood does not mix with oxygenated blood

6. Milk  Females only  Mammary glands are modified sweat glands that produce the milk

7. Single jawbone  Unlike other animals there is only one lower jawbone  Important in identifying mammal remains due to decay of other characteristics

8. Specialized teeth  Front teeth for biting and cutting  Side and back teeth for grinding

9. Mammalian Ancestors  300 million years ago there were two major groups of animals –One group gave rise to dinosaurs, birds, and all living reptiles –The other group, the synapsids, gave rise to mammals and their relatives  Opening behind the eye in their skull

10. Dimetrodon

11. Therapsids  The group that rose from the synapsids and gave rise to mammals  Many transitional forms  Very complete fossil record  Single jawbone witnessed  Limbs moved under the body  Specialized teeth evolved  Some may have been endothermic and had hair

12. Lycaenops

13. First Mammals  Appeared the same time as the dinosaurs—Triassic period  Very small fossil remains  Large eye sockets suggests nocturnal existence

14. First Mammals  By the end of the Jurassic, 5 orders of mammals had evolved  Midway through the Cretaceous, 3 main groups had evolved

15. Three Main Groups of Mammals  Monotremes—the egg layers  Marsupials—live birth, but short internal development—pouched animals  Placentals—live birth, long internal development, young nourished through a placenta

16. Diversification of Mammals  Dinosaurs died out 65 mya  New habitats and niches opened up and allowed evolutionary diversification

17. Benefits of Endothermy  Able to live in cold climates  Energy is available to perform tasks for long periods of time  Organ systems are arranged differently  Food intake is increased  Insulation to heat loss through hair and fat layers

18. Respiratory System  Very efficient system  Large lungs and many alveoli for gas exchange  Diaphragm to aid inhalation

19. Tooth Types  Incisors to cut  Canines to grip and puncture  Premolars to shred and grind  Molars to grind and crush  Baleen in whales

20. Plant Digestion  Cellulose  Multi-chambered stomach  Rumen—contains microorganisms  Regurgitate and chew the partially digested cud  Cecum—fermentation chamber

21. Nervous Systems and Sense Organs  Enlargement of cerebrum accounts for the large brains of mammals –Evaluates input –Controls movement –Initiates and regulates behavior  Five senses  Various heightened senses depend on environment, Ex. Bats and echolocation

22. Monotreme Reproduction  Lays one to two leathery eggs and incubates them  Developing embryo is nourished by the yolk

23. Marsupial Reproduction  Very short internal development  At the point when they can survive outside the mother’s body they emerge and move into the pouch

24. Placental Mammal Reproduction  Most familiar type of mammal reproduction  Long development  Nourished through a placenta containing blood vessels of mother and offspring

25. Order Monotremata  Egg-layers  Three species –Platypus –Two types of anteater or echidna  Platypus –Aquatic adaptations—webbed feet, flattened tail, duckbill muzzle –Nippleless mammary glands  Echidna –Terrestrial –Coat of protective spines –Probing nose

26. Order Marsupialia  About 280 species  Only one U.S. species—Opossum  Inhabit Australia, New Guinea, Americas  As Pangea drifted apart the isolation allowed for diversification and domination in certain regions of these organisms—many were replaced by placental mammals

27. Placental Mammals  Order Rodentia  Order Edentata  Order Lagomorpha  Order Insectivora  Order Primates  Order Chiroptera  Order Carnivora  Order Artiodactyla  Order Perissodactyla  Order Cetacea  Order Sirenia  Order Proboscidea

28. Order Rodentia  Largest order with about 1800 species, about 40% of all placental mammals  Not found on Antarctica  Two pairs of incisors  High reproductive capacity

29. Order Edentata  About 30 living species  Anteaters, sloths, armadillos  Edentata means “toothless”, anteaters have no teeth, armadillos and sloths have peg-like teeth with no enamel

30. Order Lagomorpha  Roughly 70 species including rabbits, hares, and pikas  Double row of upper incisors

31. Order Insectivora  About 390 species  Shrews, hedgehogs, moles  High metabolic rate  Found in North America, Europe, Asia, and Africa  Pointed, probing noses  Arboreal, subterranean, or terrestrial adaptations

32. Order Primates  235 species  Prosimians—lemurs, tarsiers, lorises  Anthropoids—monkeys, apes, humans  Omnivorous  Large brains  Variation in size-from 10 grams to 400 lbs.  Forward facing eyes, and grasping hands

33. Prosimians

34. Anthropoids

35. Order Chiroptera  More than 900 species  Bats  Wing is a modified hand with a membrane stretched over it

36. Order Carnivora  274 species  Dogs, cats, bears, raccoons, seals, hyenas, etc.  Meat eaters that typically have long canines, strong jaws, and clawed toes  Long limbs to aid in running  Pinnipeds—aquatic such as seals, walruses

37. Order Artiodactyla  About 210 species  Also known as the ungulates or hoofed mammals—have even number of toes  Deer, elk, sheep, goats, pigs, camels  Native to every continent except Australia and Antarctica  Use speed as defense  Typically herbivores  Rumen

38. Order Perissodactyla  17 living species  Ungulates with odd number of toes  Horses, zebras, rhinoceroses, tapirs  Most are native to Africa and Asia  Tapirs can be found in Central and South America  Cecum instead of rumen

39. Order Cetacea  90 species of whales, dolphins, and porpoises  Forelimbs are flippers, hind limbs modified to flippers  Blowholes and blubber  Echolocation for navigation  Entirely aquatic, but evolved from land mammals  Toothed whales and baleen whales

40. Toothed versus Baleen

41. Order Sirenia  4 species  Manatees and dugongs  Inhabit rivers, estuaries, and tropical waters  Flippers and no hind limbs like cetaceans  Closely related to elephants

42. Order Proboscidea  3 species  Boneless, trunked nose, or proboscis  Elephants  Modified incisors called tusks  Long gestation  Live to about 80