If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Biology

History of life on Earth

Biology

History of life on Earth

Lessons

Formation of Earth and early life

Learn
Earth formation
(Opens a modal)
Beginnings of life
(Opens a modal)
Origins of life
(Opens a modal)
Hypotheses about the origins of life
(Opens a modal)

The diversification of life

Learn
Ozone layer and eukaryotes show up in the Proterozoic eon
(Opens a modal)
First living things on land clarification
(Opens a modal)
Biodiversity flourishes in Phanerozoic eon
(Opens a modal)
Human evolution overview
(Opens a modal)

Radiometric dating

Learn
Chronometric revolution
(Opens a modal)
Carbon 14 dating 1
(Opens a modal)
Carbon 14 dating 2
(Opens a modal)
Potassium-argon (K-Ar) dating
(Opens a modal)
K-Ar dating calculation
(Opens a modal)
Atomic number, atomic mass, and isotopes
(Opens a modal)

About this unit

Our planet has an amazing history spanning about 4.5 billion years! Learn more about how Earth formed, the early history of life on Earth, and the origins of humans.
Biology is brought to you with support from the
Amgen FoundationAmgen Foundation