Geologic Time

Scroll through the page below to get an idea of the immensity of geologic time.

First rocks
Oldest fossils of bacteria
Oldest fossils of eukaryotic cells
Algae and soft-bodied bilateral animals form

Animals diversify; some develop shells, external skeletons or notochords

Algae multiply
First fish
Plants and arthropods colonize land

Vascular plants form and diversify

Diversification of bony fishes
First amphibians and insects

Forests of giant seed ferns cover the Earth
Reptiles form; amphibians are widespread

Reptiles spread
Origin of most present-day orders of insects
Mammal-like reptiles form

Cone-bearing plants form
Dinosaurs spread

Dinosaurs and gymnosperm plants continue to diversify and spread
First birds and mammals form

Origin and spread of flowering plants and hardwood trees
Dinosaurs become extinct

First primates
Whales and dolphins return to the sea
Earliest apes

Common ancestor to both apes and humans
Oldest fossils of hominids; walked fully upright

Homo erectus appears

First civilization arises

Present day