MYA	EON	ERA	PERIOD	EPOCH	MAJOR EVENTS
0.01	P H A N E R O Z O I C	C E N O Z O I C	Quarternary	Recent	Development of agriculture and human civilization
1.8				Pleistocene	Appearance and world-wide spread of the genus Homo. Repeated glaciations. Extinctions of large mammals and birds.
5.2			Tertiary	Pliocene	Continued diversification of modern birds, placental mammals, snakes, teleost fish, pollinating insects, grasses and angiosperms.
24				Miocene
34				Oligocene
56				Eocene
65				Paleocene
144		M E S O Z O I C	Cretaceous		Diversification of flowering plants, birds and mammals.
206			Jurassic		1^st birds and angiosperms. Dinosaurs abundant.
251			Triassic		1^st dinosaurs and mammals. Gymnosperms become abundant. Continents moving apart.
290		P A L E O Z O I C	Permian		Diversification of reptiles, including mammal-like species. Land masses form single continent, Pangea.
354			Carboniferous		1^st reptiles and winged insects. Warm humid conditions result in huge forests of primitive plants, which formed extensive coal deposits.
409			Devonian		1^st amphibians and true insects. Atmospheric oxygen at present levels or higher. Continents moving toward one another.
439			Silurian		1^st land plants. Atmospheric oxygen about 20 percent.
500			Ordovician		1^st fish.
543			Cambrian		1^st shelled organisms. Trilobites abundant. Probably all metazoan phyla present, including arthropods and early chordates. Atmospheric oxygen reaches about 2%.
2,500	PROTEROZOIC				Abundant prokaryotic life. Eukaryotes may have appeared by 2,000 million years ago. Atmospheric oxygen about 0.2%.
3,600	ARCHEAN				Oldest known rocks and prokaryotes.
4,600	HADEAN				Earth forms. No geological record.

From Futuyma (1998), p. 130, using dates of Jablonski et al. (1996).