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Evolution exam 2

Precambrian- time range 3800-570mya
Origin of life Precambrian
Archaea and bacteria, O2 released in atmosphere Precambrian
Four Eras Precambrian, Paleozoic, Mesozoic, Cenozoic
Paleozoic- time range 570-245 mya
Periods of Paleozoic Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian
Cambrian- time 570 mya
sea life, earliest vertebrates Cambrian
Cambrian radiation increase O2, Hox genes, most body plans evolved in this era
Cambrian extinction global coolning and O2 depletion, glaciers form and sea levels fall, cool waters
Cambrian extinction- species trilobite, echnoderms
Ordovician- time 505 mya
1st fish Ordovician
Ordovician extinction nearly as bad as Permian, landmass passed over north pole, massive ice sheets formed, sea level decreased
Silurian- time 438 mya
1st land plant Silurian
Devonian-time 408 mya
1st amphibians Devonian
lobe and ray finned fish Devonian
Land really gets going Devonian
Devonian extinction glaciation, possible meter impacts
Devonian extinction- species mostly marine life, reef builders lost, brachipods, jawless fish, trilobites
Carboniferous- time 360 mya
1st reptiles Carboniferous
Permian- time 286 mya
1st modern insects Permian
winged insects Permian
tropical climates, swamp forests Permian
Permian extinction cause unclear, "big one," Pangea formed
Permian extinction- species 96% of all skeleton bearing marine species, trilobites, pelycosaurs
Periods of Mesozoic Triassic, Jurassic, Cretaceous
Mesozoic- time range 245-66 mya
Triassic- time 245 mya
1st mammals Trassic
1 lower jaw, 3 ear bones, differentiated teeth mammals
Pangea breaks up Trassic
Warm climate Trassic
Synapsid therapods were ancestrak Trassic
Jurassic- time 208 mya
dinosaurs dominant Jurassic
birds Juraasic
Synapomorphy is not feathers(birds) opposable hind toe, hollow bones
Modern birds keeled breast bone, no teeth, no claws
Cretaceous- time 144 mya
dinosaurs extinction Cretaceous
Angiosperms Cretaceous
insects diversify and social insects evolve Cretaceous
Cenozoic- time range 66- present
Early Cenozoic- time 66 mya
1st large mammals and primitive primates Early Cenozoic
formation of Himalayas Early Cenozoic
grasses are popular Early Cenozoic
origins of most modern mammals, rodents Early Cenozoic
North America isolated from Europe, Gondwanaland breaks up, Panama, Australia separates Early Cenozoic
Late Cenozoic- time 23.7 mya
development of most modern mammals and birds Late Cenozoic
ape like ancestor of humans appear Late Cenozoic
Late Cenozoic- extinction big land and water animals get large and then die out
Pleistocene- time 1.6 mya
ice age begins Pleistocene
Pleistocene ice age glaciations cause decrease in sea level and extinction
earliest humans Pleistocene
Present- time .01 mya
ice age ends Present
Created by: ccorcoran19