Term
|
Definition
3.8 bya
(GEO) O2 first appears in atmosphere
(HIST) - origin of life, prokaryotes flourish |
|
|
Term
|
Definition
1.5 bya
(GEO) O2 level at >1% current level
(HIST) eukaryotes evolve, several animal phyla appear |
|
|
Term
|
Definition
600 mya
(GEO) O2 level at >5% current level
(HIST) ediacaran fauna |
|
|
Term
|
Definition
542-488 (beginning Paleozoic)
(GEO) O2 levels approach current levels
mild climate
(HIST) cambrian explosion, all existing phyla develop
1st vertebrates, earliest primitive fish |
|
|
Term
|
Definition
488-444 (Paleozoic)
(GEO) massive glaciation, sea levels drop 50m
global cooling, glaciation, volcanism
(HIST) primitive fish, seaweed, fungi, echinoids
primitive land plants
mass extinction at end (~75% lost) |
|
|
Term
|
Definition
444-416 (Paleozoic)
(GEO) sea levels rise
2 large continents form
hot/humid
(HIST) jawless fishes diversify
1st jawed, ray-finned fish
plants and animals colonize land
vascular plants |
|
|
Term
|
Definition
416-359 (Paleozoic)
(GEO) continents collide at end of period
meteorite
(HIST) fishes diversify (sharks, bony)
land plants diversify
1st insects and amphibians (tetrapods)
mass extinction at end (~75%) |
|
|
Term
|
Definition
359-297 (Paleozoic)
(GEO) climate cools
marked latitudinal climate gradients
(HIST) coal swamps, ferns
amphibians more common
first winged insects |
|
|
Term
|
Definition
297-251 (end Paleozoic)
(GEO) continents aggregate into pangaea
large glaciers form
dry climates in interior of pangaea
(HIST) reptiles diversify
amphibians decline
gymnosperms dominate plant life
phytoplankton and plants oxygenate Earth (to close to today's levels)
first flies, beetles
mass extinction at end (~96%: trilobites extinct, most animals/marine/trees) |
|
|
Term
|
Definition
251-200 (beginning Mesozoic)
(GEO) pangaea begins to drift apart
hot, humid
(HIST) first dinosaurs, mammals, ancestral crocs
marine invertebrates diversify
mollusks are dominant invertebrate
first flowering plants
many reptiles (turtles)
ends with mass extinction (~65%: marine reptiles) |
|
|
Term
|
Definition
200-145 (Mesozoic)
(GEO) two large continents form: Laurasia (N) and Gondwana (S)
climate warm
(HIST) dinosaurs diversify
radiation of ray-finned fish
pterosaurs and Archaeopteryx appear
first flowering plants
many ferns, gingkos, conifers |
|
|
Term
|
Definition
145-65 (end Mesozoic)
(GEO) northern continents attached
gondwana drifts apart
meteorite to yucutan peninsula at end
(HIST) dinosaurs continue to diversify
flowering plants and mammals diversify
crocodilians, feathered dinos, snakes
butterflies, ants, bees
primitive marsupials
mass extinction at end (75%: dinosaurs, pterosaurs) |
|
|
Term
|
Definition
65-1.5 (Crenozoic)
(GEO) continents near current positions
climate cools
(HIST) diversification of mammals, birds, flowering plants, insects
first hominids, whales |
|
|
Term
|
Definition
1.5 mya-present (Crenozoic)
(GEO) cold/dry
repeated glaciations
(HIST) first humans evolve
megafauna evolve, become extinct |
|
|
