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20 Cards in this Set
- Front
- Back
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# species mammals %marine |
5500 (3%marine) |
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# species marine mammals |
pinnipeds (33) sea otter polar bear sirenians (4) cetaceans (87) |
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mammals evolved from _____ lineage evolutionnn |
synapsid "mammal-like reptiles" Carboniferous therapsids-mid permian higher metabolic rates endothermy diversification of teeth -heterodonty more upright posture |
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1st mammals |
early jurassic -small and insectivorous endothermy hair mammary glands viviparity (except monotremes) -all mammals=placental locomotion changes (lateral bending to dorso-ventral bending) |
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polar bear |
ursus maritimus from siberian population of brown bears mid-pleistocene longer neck, smaller head circumpolar 20,000 population prefer periodically active ice 90% of diet-ringed seals (1 every 6 days) |
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sea otter |
enhydra lutris family mustelidae -(river otters, skunks, weasels, badgers etc) smallest marine mammal dense insulating fur, traps air flat tail and hind feet=swimming, front=grooming/eating near shore-kelp beds 1911=1000 left now 130,000 north pacific 1 pup/yr |
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sirenians |
families= dugongidae, trichechidae early tertiary elephants/aardvark sluggish herbivores tropical and subtropical no hind limbs short fore-flippers=stability enlarged horizontal tail no external ears give birth underwater to 1 calf |
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dugongidae |
dugong 1 species left= dugong dugon fluke tail like dolphin split upper lip indian and west pacific oceans |
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stellar's sea cow |
hydrodamalis gigas dugongidae north pacific known in 1741 hunted to extinction by 1768 |
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trichechidae |
manatees round tail seas and rivers 3 species west african-tichechus senegalensis caribbean-t. manatus amazonian-t. inunguis -freshwater |
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pinnipeds characters |
related to terrestrial carnivores streamlines thick blubber flexible land for birth carnivorous-krill, fish, squid, molluscs, crustaceans, marine mammals, birds (depends) some capable of deep diving weddell seal (73min, 600m) elephant seal (62min 1250m) |
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pinniped 3 families |
phocidae-tur earless seals, 19species
otariidae-fur seals and sea lions, 15 species
odobenidae-walrus |
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monophyletic or diphyletic pinnipeds |
debate monophyletic-30mya same bearlike ancestor diphyletic-20mya independent, phocidae-otters, otariidae and odobenidae-bears and dogs |
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phocidae |
no external ears hind flippers can't turn forward short neck mostly marine swim w lateral motion of hind flippers only elephant seal forms mating harems 2 subfamilies: --monachinae-monk antarctic, elephant --phocinae-northern, hooded, bearded (all n hemi) |
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monachinae |
tropical monk seals-hawaiian, mediterranean, carribean (extinct)
antarctic-crabeater, leopard, weddell, ross
elephant-northern and southern, temperate, male has long proboscis (nose thing) |
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phocinae |
bearded seal-long whiskers, arctic
hooded-arctic, long proboscis, can inflate red balloon sac from 1 nostril
grey seal-n atlantic
seals of genus phone-harbor, ringed, caspian, Baikal, harp, ribbon, divers, arctic and north temperate Pac and Atlantic |
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otariidae |
pinna (ears) hind flippers turn under on land long neck marine long front flippers to swim none in north atlantic harems (polygynous) 2 subfamilies: --arctocephalinae-fur seals --otariinae-sea lions |
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arctocephalinae |
fur seals pointed muzzle, longer fore-flippers, thick fur coat most in southern hemisphere except N fur seal=subarctic n pac 8 species |
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otariinae |
sea lions rounded snout short coarse fur includes CA sea lion-zalophus californianus |
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odobenidae |
walrus!!! circumarctic near pack ice tusks largest and heaviest pinniped except male elephant seals -3-5m, 1400kg smaller fore-flippers than otarids --swim w hind flippers but can turn under to walk lack external ears loss of fur in adults fleshy snout w long vibrissae to find clams and other bivalves in mud |
