-
500
the formation of earth
4.5 BILLION YEARS AGO
radiometric dating of meteorites deposit on earth -
520
Hadean Eon
4.6-4.0 BILLION YEARS AGO
period from earths formation to approximate time of emergence of life, moon formed, no life exists -
Jan 1, 650
Archaen Eon
4.0-2.5 BILLION YEARS AGO
most rock was lava/magma based
atomosphere lacked free oxygen
unicellular life existed -
Jan 1, 1000
photosynthesis
3 BILLION YEARS AGO
iron oxide in rocks could only fomr in presence of atmospheric oxygen, essential for cellular respieration -
proterozoic eon
2500-542 MILLION YEARS AGO
photosynthesis causes the oxygentation of earth, eukaryotes evolve,
endosymbiosis emerges. -
eukaryotes
1.8 BILLION YEARS AGO
fossilized cysts of primitive protists. -
multicellularity
1.2 BILLION YEARS AGO
numerous fossils genetic evidence suggests divergence of modern eukaryotes occurred. -
today
(for scale purpose)