▶Lesson video
Understanding time scales
Understanding time scales
Biology • Adaptations, competition, natural selection and evolution
The video is not available yet.
Show transcript
Evidence suggests Earth was formed 4.5 billion years ago (one billion is one thousand million).
Evidence suggests the first living organisms (microorganisms) appeared around 3.8 billion years ago.
The oldest fossils are around 3.5 billion years old, and the newest fossils are around 10 thousand years old.
Evidence suggests the first land plants appeared 500mya, the first mammals 200mya, and modern humans 350k years ago.
Scientists divide Earth’s history into eons, periods and epochs to make it easier to understand.