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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

reptiles

diapsids and anapsids


ectothermic poikilotherm


scales ,


4 bones in lower jaw


teeth replaced all the time



mammals

go back to late triassic


2 lineages


pelycosaurs and therapsids



pelycosaurs

look like reptiles


high spines , could have been used for thermoregulation


synapsid condition only connects to mammals


1 opening in skull

therapsids

stem group that led to mammals


1 lineage led to mammals


cynodonts led to mammals

Hadrocodium wui

extinct sister group to mammals


insectivore and 2 grams in weight

living mammals

4554 species


monotremes, marsupials. eutherians (placentals)


all monophyletic



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

platypus

fur , aquatic, lactate but lay eggs , males have venom


genome is reptile and mammal



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

eomaia scansoria

earliest known placental animal


early cretaceous

eutherian placental

diversified after K-T extinction


but molecular clocks sugggest to cretaceous



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



eutherian

19 orders


braincase expanded


teeth most IMPORTANT 3incisors 1canine 4premolars 1 molar





afrotheria

monophyletic group


elephant, shrew aardvark, sea cow,



xenarthra

aramadillos, anteaters, sloths



Laurasiatheria

moles, shrews

Euarchontoglires

primates , rodents, rabbits,