Earth forms

Hadean

Oldest rock

Hadean

First evidence of life

Archean

First fossils

Archaean-Paleoarchean

Oxygen in atmosphere 

Proterozoic-Paleoproterozoic

First abundant life found in the rock record

Proterozoic-Paleozoic-Cambrian

First fish

Phanerozoic-Paleozoic-Cambrian

first land plants

Phanerozoic-Paleozoic-Ordovician

largest mass extinction occurs

Paleozoic-Mesozoic

First dinosaurs

Phanerozoic-Mesozoic-Triassic

First mammals

Phanerozoic-Mesozoic-Triassic

breakup of super-continent Pangaea begins

Phanerozoic-Mesozoic-Jurassic

first flower plants

Phanerozoic-Mesozoic-Cretaceous

dinosaurs and other animals go extinct

cretaceous-paleogene extinction

first primate in genus Homo

Phanerozoic-Cenozoic-Pliocene

first Homo sapiens

Phanerozoic-Cenozoic-Quaternary-Pleistocene

humans first inhabit North America

Phanerozoic-Cenozoic-Quaternary-Pleistocene

End of last Ice Age

Phanerozoic-Cenozoic-Quaternary-Holocene

European rediscovery of the Americas

Phanerozoic-Cenozoic-Quaternary-Holocene