The Geological Time Scale
What is the Geological Time Scale?
The geological time scale is a timeline of Earth’s history. It shows when major events happened, like:
Formation of Earth.
Appearance of plants and animals.
Mass extinctions.
Evolution of humans.
Definition.
The geological time scale is a system used by scientists to divide Earth’s history into different time periods based on rock layers, fossils, and major events.
Key Points.
The geological time scale is a timeline of Earth’s history.
It shows events from Earth’s formation to the present.
Earth is about 4.6 billion years old.
The time scale is based on rock layers and fossils.
Older rocks are found below younger rocks.
Earth’s history is divided into eons, eras, periods, and epochs.
What is the Evolution of Humans?
Human evolution is the slow change of humans over millions of years.
1. Early Apes.
Looked like apes.
Could walk on two legs sometimes.
2. Australopithecus.
Walked upright.
Small brain.
Lived in Africa.
3. Homo habilis.
Used simple stone tools.
Bigger brain than earlier humans.
4. Homo erectus.
Walked fully upright.
Used fire.
First to leave Africa.
5. Homo sapiens.
Large brain.
Use language, art, tools.
Fun Fact
More than 99% of all species that have ever lived on Earth are now extinct.