Earth is the only planet we know of that supports life. Its surface is made up of large areas of land (continents) and even larger areas of water (oceans and seas). The way land and water are arranged today is not how it always looked. Over millions of years the surface of the Earth has changed slowly but greatly.
A changing planet
The outer shell of the Earth is broken into huge pieces called plates. These plates move very slowly, only a few centimetres each year. Over a very long time this movement causes continents to shift, mountains to rise, and oceans to widen. The climate — the usual weather of a place over many years — has also changed many times. Some ages were much colder and some were much warmer than today.
Why this matters for history
Changes in the land and climate decided where early humans could live. When it was cold, thick ice covered much land and sea levels fell, joining islands to the mainland. When it warmed, ice melted and the sea rose again, separating them. People and animals moved to follow food, water and warmth.
Key idea
The Earth's surface and climate are always changing. These natural changes shaped the world in which the first humans lived and moved.
Remember
- Earth's surface is land and water, arranged differently in the past.
- Moving plates and changing climate reshaped the world over millions of years.
- Colder and warmer ages changed sea levels and where people could live.