Chapter 26: Mammals 1

Transcription

1 Chapter 26: Mammals 1

2 Phylogenetic Tree 2

3 Kingdom: Animalia Subphylum: Vertebrata Phylum: Chordata Class: Mammalia 19 orders Over 5,000 species 3

4 Mammals Most of today s large land animals Most terrestrial Some swim and fly VERY efficient at retaining water 4

5 Key Characteristics 1) Hair 2) Diverse and specialized teeth 3) Endothermic metabolism 4) Mammary glands that produce milk Also have kidneys that concentrate waste into small volume of urine 5

6 1) Hair Primarily dead cells filled with keratin Only mammals Primary function = insulation 6

7 1) Hair Color change = camouflage Provide warning EX: SKUNK ALERT! I WILL STINK YOU RIGHT OUTTA HERE! Detect vibrations or protect Ex: Quills and whiskers Humans need clothes - sparse hair and limited fat 7

8 2) Teeth Usually 2 sets A) Baby teeth (Milk teeth) B) Permanent Teeth Uses: Secure & Chew food Protection Threat signal Perform Tasks 8

9 2) Teeth 4 types: 1. Incisors In front Biting and cutting 2. Canines Stabbing and holding 3. Premolars crushing and grinding 4. Molars Crushing and grinding = faster digestion 9

10 2) Teeth Highly specialized Can determine diet by teeth Which skull is from a herbivore? 10

11 3) Body Temperature ENDOtherms - Generate heat internally by rapid metabolism of food active day or night Can live in very cold climates 11

12 3) Body Temperature Sustain activities that require lots of energy Running, flying or swimming Must eat 10x more food than ectotherm of similar size Need efficient respiratory and circulatory systems 12

13 Respiratory System Diaphram Sheet of muscle that separates chest and abdominal cavities Contracts = chest cavity enlarges Alveoli Draws air in Grape-shaped chambers Increase surface area More active = have smaller, but more Increase efficiency 13

14 Heart and Circulatory System 4 chambered heart Septum completely divides ventricle Double loop Oxygenated and deoxygenated blood does not mix! 14

15 4) Mammary Glands On female s chest or abdomen Produce nutrient-rich milk High in protein, carbohydrates, and fat Water (prevents dehydration) and minerals Ex: Calcium Weaning - time when mother stops nurses young 15

16 Parental Care Young depend on mother for long time Primates = longest Male involvement varies Some learn survival skills with parents 16

17 Mammalian Diversity Size Shrews- 1.5 grams Blue Whales 150 tons Anatomy Bat Forelimbs modified into wings Body covered with hair Whale Habitat Forelimbs flattened and paddle shaped No hind limbs Nearly hairless, streamlined body Both use echolocation Bat Fly, active at night Manatee Aquatic 17

18 Reproduction All use internal fertilization One or more eggs fertilized Variation in how/where zygote develops 3 groups (based upon developmental pattern) 1. Monotremes 2. Marsupials 3. Placental mammals 18

19 1) Monotremes Most primitive 1 order (Monotremata) Australia and New Guinea 3 living species Duck-billed Platypus 2 species of Echidnas (Spiny anteaters) Lay eggs Leathery shells Female incubates eggs At hatching, newborns only partially developed 19

20 1) Monotremes Only group of mammals to have a Cloaca - common passageway for digestive, reproductive, and urinary systems Adults do not have true teeth Have hair and produce milk No nipples Milk oozes from glands on mother s belly 20

21 1) Monotremes Platypus Lakes and streams in Australia Broad, flat, webbed feet Eats crustaceans, worms, and snails Echidna Terrestrial Sharp, strong claws Elongated, beak-like snout Burrow and dig for insects and invertebrates 21

22 2) Order Marsupialia Kangaroos Wombats Wallaroos Koalas Opossums 22

23 2) Marsupials Young born days/weeks after fertilization Tiny and undeveloped except for front limbs Newborns crawl to pouch (marsupium) and attach to nipple Grow and emerge, but return to nurse 23

24 2) Marsupials Most in Australia region Result of Pangaea? Australia region broke apart from Antarctica and South America 24

25 3) Placental Mammals Young develop in uterus and nourished from blood Placenta Organ Allows diffusion of nutrients and oxygen from mother s blood Waste materials leave 25

26 3) Placental Mammals Gestation period Time between fertilization and birth Longer than marsupials More completely developed at birth Some stand and walk within hours Others blind, deaf, and helpless 26

27 3) Placental Mammals Vary in size, shape, diet, and habits Variety of habitats Hot to frigid 27

28 3)Placental Mammals Hooves Specialize pad covering toes Made of Keratin 28

29 3) Placental Mammals Horns Core of bone surrounded by sheath of keratin Attached to skull NEVER SHED! Both sexes have Note: Horns of a rhino are composed of hair-like keratin fibers NOT bone 29

30 3) Placental Mammals Antlers Males only Made of bone Covered by velvet (soft skin) NOT covered by keratin sheath When done growing, velvet dries and falls off Uses: attract females combat other males Shed after breeding season Grow larger each year indicating age 30

31 3) Placental Mammals Domestic Animals Kept and bred purposefully Many selectively bred More milk Fine hair Strength Hybrids - 2 different species - EX: Mules 31

32 Orders of Placental Mammals 19 including: 1. Order Rodentia 2. Order Chirotera 3. Order Insectivora 4. Order Carnivora 5. Order Pinnipedia 6. Order Primates 7. Order Artiodactyla 8. Order Perissodactyla 9. Order Cetacea 10. Order Lagomorpha 11. Order Sirenia 12. Order Probascidea 32

33 Order Rodentia 40% of all mammals Specialized gnawing teeth 2 pairs of large, curved incisors Grow continuously Intelligent Small Rapid Reproduction 33

34 Order Rodentia 1,500 living species All continents except Antarctica Ex: Hamsters, guinea pigs Beavers, muskrats, porcupines Woodchucks, chipmunks, squirrels, prairie dogs, and chinchillas We will discuss Rodents in detail with our dissection lab! 34

35 Order Chiroptera Greek = hand wing Ex: Bats Capable of true flight Front limbs modified into wings Live in groups Nocturnal Most carnivorous Use echolocation 35

36 Side notes on Bats ~ 1000 species Two groups 1. Megabats (Old World fruit bats) Large Africa, India, Australia, and Asia 2. Microbats Small Everywhere! Smallest bat Kitti's hog-nosed bat (1 in) long Largest Bat Malayan flying fox (16 in) and has a wingspan of 5.6 feet. 36

37 Side notes on Bats Hibernation/Migration Bats in WI survive by migrating or hibernating in caves or mines. Move to trees or buildings during summer. Some reside in caves year-round, using different caves in summer than winter Most return yearly to the same caves Tree bats usually roost in trees during summer and spend winter in hollow trees. Some make long migration flights Brazilian (or Mexican) free-tailed bats spend summer in SW U.S. caves and migrate up to 800 miles to Mexico. 37

38 Misconceptions Not flying mice Not blind Most see as well as us! Fruit bats even see in color. Do not try to become tangled in hair. Bats have built in sonar hat allows them to navigate at break-neck speed through total darkness. Not ugly (well, you decide) or dirty. They spend an enormous amount of time grooming their fur. 38

39 Misconceptions Not all are vampires. Only three are and are mostly in Latin America. Bats don t carry rabies. They are capable of catching the disease just like any other mammal. Less than 0.5 % of bats contract rabies. Grounded bats are more likely to be sick. NEVER pick up barehanded. Bats are among the slowest reproducing animals. Most have only one young per year. Average life-span of a bat is 25 to 40 years 39

40 Side notes: Bats in Danger! White nose syndrome A serious fungal disease Affecting bats in NE US Rings of white found around the nose Most fungus is on the bats bodies and not found internally Threaten to add several types of bats to the endangered species list. Indiana bat is seen as at special risk Many species of bats winter together in a caves causing the spread 40

41 White-Nose Syndrome 41

42 Order Insectivora Eat mainly insects but also fruit, small birds, and snakes Large appetite Shrews eat 2X their body weight daily Very high metabolic rate 42

43 Side notes: Insectivora Long-pointed, flexible snouts Well developed sense of touch Poor sight and hearing All have musk glands Shrews: very short life and high reproductive rate Female becomes pregnant within hours of giving birth The pygmy shrew is the smallest mammal in North America More than 70% of the Insectivora are shrews Other members include moles and hedgehogs 43

44 Order Carnivora 2 groups 1. Cat Family 2. Dog Family Strong Intelligent Keen sense of smell, vision, and hearing Long canine teeth Most carnivorous Raccoons, bears are omnivores Pandas are herbivores 44

45 Dog Family Gray Wolf Coyote 45

46 Wolves Largest wild members of dog family Two species still living: 1. Gray wolves (Timber wolves) 2. Red wolves Known for pack structure and complex social behavior 46

47 Wolves 3,000 to 5,000 wolves in early 1800s A state bounty was placed on wolves in Wisconsin in 1865, and lasted until By 1900, wolves had disappeared from southern Wisconsin. In 1950, less than 50 wolves remained in extreme northern Wisconsin. In 1957 wolves were protected, but by1960 were considered extinct. In 1967 and 1974 the U.S. Fish and Wildlife Service designated the timber wolf a federally endangered species. In 1975, wolves began to re-colonize Wisconsin in the northwest portions of the state, along the Minnesota border Wisconsin DNR completed a wolf recovery plan in there were over 809 wolves 47

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50 Coyotes Smaller About 15 kg (33 lb) family groups consisting of pair of adults and offspring Usually hunt alone but may hunt with one or two others Now reproduce in metropolitan areas 50

51 Jackals 4 species in eastern hemisphere Slender and smaller than coyotes Big feet and fused leg bones Capable of running 9.9 mph for extended periods of time Crepuscular -most active at dawn and dusk. 51

52 Foxes Largest group 21 species 1.5 to 9 kg (3 to 20 lb). Pointed muzzles Long and bushy tails Large ears. Stalk prey and leap on it with stiff-legged pounce Live in groups of up to 6 52

53 Dog Family Tracks meander, show claws 53

54 Family Felidae Strictest carnivores of mammals Most solitary Secretive Nocturnal Live in relatively inaccessible habitats Around ¾ of cat species live in forested terrain Agile climbers Native to every continent except Australia and Antarctica Cat Family 54

55 Side Notes: WI Cats 3 wild cats native to WI 1. Cougar 2. Bobcat 3. Canada Lynx Only known breeding wild cat in the state (Cougar) A fall population of about 3000 in northern Wisconsin, and lower numbers in other portions of the state 55

56 Side Notes: The Cougar Also known as: Puma Mountain Lion Panther American Lion Catamount January 18, 2008 a cougar was sighted near Milton, Wisconsin. Was verified as 'cougar' from the tracks and DNA from a small drop of blood from a cut on the foot. Wisconsin DNR is continuing to investigate sightings and tracks in Rock and Walworth Counties 56

57 Side Notes: The Cougar Largest cat in US In the Americas, only the jaguar is larger Ave: 75 to 160 pounds Some males upto 265 pounds Males are 72 to 95 inches in total length Tail is 28 to 38 inches in length Adults ~ 27 to 31 inches at the shoulder 57

58 Tracking 58

59 Tracking 59

60 Side Notes: The Bobcat ~ 20 pounds Large ears with pointed tufts of hair at ends Orange-tan pelt with black stripes on face and spots on body Top of tail is black with white underside Confused with the lynx Bobcat is slightly smaller Irregular dark markings only on top half of tail Shorter tufts of hair on ears 60

61 Side Notes: Canadian Lynx Ear tufts usually longer than 1 inch Tail is gray with black tip Longer back legs help in springing to catch prey Large paws allow them to walk on snow Favorite Food: Snowshoe Hare Biologists estimate that for every animal a lynx captures, it misses ten. On average, a lynx kills every other night, eating hares a year. 61

62 Order Pinnipedia Marine Carnivores Seals and sea lions Feed in ocean Rest, mate, and raise young on land All 4 limbs modified into flippers Streamlined bodies Insulating layer of blubber Most live in large colonies (rookeries) headed by single male 62

63 Side Notes: Pinnipedia true seals no ear flap Largest: Elephant seal 2200 kg, weight of a minivan Smallest: Ringed seal 50 kg, size of a small dog Newborns have no blubber Trap warmth and energy from sun beneath fur Shed fur Have nictating membrane Nostrils close underwater 63

64 Side Notes: Pinnipedia Most live around Antarctica and Arctic Circle Antarctica has no permanent land mammals, but six species of seals Whiskers help them navigate Relate to direction and sound under water, with the help of the sensors in their skull Feed on krill, herring, flounder, and salmon Bulls breed several dozen females in a single season and have exclusive harems 64

65 Side Notes: Pinnipedia Walruses 2 species 1. Pacific Walrus 2. Atlantic Walrus Prominent Tusks = elongated canines - Over a meter long - Both males and females have - Used to display dominance and make and maintain holes in ice Up to 4,500 pounds Favorite food: clams on the ocean floor Hunted for meat, fat, bones, fur, and tusks, which led to over-harvesting 65

66 Side Notes: Pinnipedia Walruses Sparsely covered with fur Blubber layer up to 15 cm (5.9 in) thick Air sac under throat Acts as flotation bubble Allows vertical bobbing in water and sleep Live ~ 50 years Gestation period months 66

67 Order Primates Humans, monkeys, and apes Most are tree dwellers Flexible, grasping hands and feet Tail used for balance Excellent depth perception Very curious High learning ability 67

68 Primates Nails instead of claws Broad and flat On at least one finger or toe Sensitive pad Stereoscopic vision enhanced sight Reduced sense smell Rely on vision more than olfaction (smell) Increased brain size and complexity 68

69 Chimpanzee Gibbon Spectacled Langur Golden Snub Nosed Monkeys Patas Monkey 69

70 Colobus Monkey Red Colobus Monkey Colobus Guereza Drill DeBrazzas Monkey Douc Langur Monkey 70

71 Mandrill Roloway Monkey Squirrel Monkey Spider Monkey White Faced Saki Monkey Emperor Tamarin 71

72 Order Artiodactyla Ungulates: Mammals with hoofs - weight supported by hoof covered toes Have EVEN # of toes Most are herbivores and live in herds Young well developed Move with herd shortly after birth Ex: Pigs, hippos, camels, deer, antelope, cattle, goats, giraffes, sheep 72

73 Order Artiodactyla Defenses: Security of the herd Run fast Have a rumen: stomach storage chamber to break down cellulose Cud - partly digested food that is regurgitated 73

74 More about Artiodactyla Pig, Red Deer, and Camel Feet 74

75 Order Perissodactyla Ungulates ODD # of toes Do NOT chew their cud Have a cecum - pouch branching from large intestine Contains microbes that digest cellulose Fewer in number than artiodactyls Ex: horses, zebras, tapirs, rhinos 75

76 Order Cetacea Two groups 1. Predatory toothed whales, dolphins, and porpoises 2. Filter-feeding Baleen Whales Streamlined bodies Modified front limbs = flippers No hind limbs Broad, flat tail Blowhole on the top of head Very intelligent Communicates with clicks and whistles 76

77 More about Cetacea 77

78 Order Lagomorpha Rabbits and hares One pair of continually growing incisors Additional pair behind front pair Long hind legs for hopping Rabbits Build nests, female lines it with fur Young born furless with eyes closed Hares No nests Young born with fur and eyes open 78

79 Order Lagomorpha Practice Coprophagy - Re-ingestion of fecal droppings First pass, food leaves partially digested Fecal pellets, rich in protein and B vitamins, are re-ingested After re-ingestion, pellets are drier and brownish when exiting Allows animals to spend little time exposed to predators Also practiced by beaver, voles, and by some shrews 79

80 Order Sirenia Sea cows Dugongs and Manatees Barrel-shaped marine animals Front limbs modified into flippers No hind limbs Flattened tail for propulsion Grazers Found in oceans, estuaries, and rivers Closely related to elephants 80

81 Side Notes: Sirenia Lungs are unlobed and flattened Lungs and diaphragm extend entire length vertebral column Helps control buoyancy and maintain horizontal position The three manatee species and the dugong are all endangered 81

82 Order Proboscidea o 2 living species o 1) African Elephant o 2) Indian Elephant o Largest land animals o Long, boneless trunk o Are right or left-tusked o Tusks differ in size, shape and angle and can be used to identify individuals 82

83 Side Notes: Proboscidea Require huge amounts of food 400 kg per day Push down large trees to get food Can be very destructive to crops and forests Live years Complex social system Excellent sense of smell Poor sight and hearing 83

84 7 Remaining Orders Summarized in table on handout (p. 816) Let s take a look... 84