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18 Cards in this Set
- Front
- Back
living mammals |
synapsids , endothermic homeotherm hair 1 bone in lower jaw other 3 bones became middle ear bones BRAIN ENLARGED MILK PRODUCTION |
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reptiles |
diapsids and anapsids ectothermic poikilotherm scales , 4 bones in lower jaw teeth replaced all the time |
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mammals |
go back to late triassic 2 lineages pelycosaurs and therapsids |
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pelycosaurs |
look like reptiles high spines , could have been used for thermoregulation synapsid condition only connects to mammals 1 opening in skull |
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therapsids |
stem group that led to mammals 1 lineage led to mammals cynodonts led to mammals |
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Hadrocodium wui |
extinct sister group to mammals insectivore and 2 grams in weight |
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living mammals |
4554 species monotremes, marsupials. eutherians (placentals) all monophyletic |
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monotremes |
mammal trait: single bone in lower jaw, 3 inner ears, hair, milk production, homeotherm Reptiles trait egglaying, shoulder girdle , cloaca present, no ears, skull platypus, echidni 3 living taxa |
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platypus |
fur , aquatic, lactate but lay eggs , males have venom genome is reptile and mammal |
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marsupials |
live birth , low gestation time, born as larval, develop in pooch, small brain, sagitall crest for jaw muscle number of teeth different dasyurids, parameloids diprotodonts convergent evolution |
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eomaia scansoria |
earliest known placental animal early cretaceous |
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eutherian placental |
diversified after K-T extinction but molecular clocks sugggest to cretaceous |
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when did eutherians diversify? |
molecular clocks estimated diversification happened into cretaceous but fossil records indicates after K-T extinction lineage has cretaceous origin but radiation after K-T extinction living groups today diversified during eocene and oligocene |
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eutherian |
19 orders braincase expanded teeth most IMPORTANT 3incisors 1canine 4premolars 1 molar |
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afrotheria |
monophyletic group elephant, shrew aardvark, sea cow, |
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xenarthra |
aramadillos, anteaters, sloths |
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Laurasiatheria |
moles, shrews |
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Euarchontoglires |
primates , rodents, rabbits, |