The history of the Earth

1. THE HISTORY OF THE EARTH The Earth’s surface is made up of water and land.

- oceans, are bodies of saltwater that cover 71% - continents, are large areas of land that cover 21% - Classification of the Earth’s surface in zones according to the material that form it: 1. Lithosphere: solid, rocky covering of the Earh’s surface.

2. Hydrospher: all he water on he Earth (it includes: oceans, seas, lakes, rivers, glaciers and underground water).

3. Atmosphere: layer of gases that surrounds the Earth (it includes nitrogen, oxigen and other gases) 4. Biosphere: thin layer of atmosphere, earth and water that life exists.

1. THE HISTORY OF THE EARH • GEOLOGY - It’s a science which study all the materials that make up the solid part of the Earth.

- Specialists: are geologists. They study: - 1. Rocks: to find evidence of all the changes that have ocurred.

- 2. Fossils: are remains of living things preserved in the rocks.

- Rocks and fossils are found in layers called strata.

- Strata are formed of sedimentary rocks which accumulate at the Earth’s surface.

1. THE HISTORY OF THE EARTH GEOLOGICAL AGES

There are 5 geological ages: 1.

ARCHAIC AGE: Water covered all the Earth Land emerged and sumerged repeatedly Earliest plants grew in the sea Fish appears about 500 million years ages 2. PRIMARY AGE: The Earth’s land masses were joined together in a single supercontinent called PANGEA. It was about 200 million years ago.

3. SECONDARY AGE: Pangea broke up into different continents that we know today.

Dinosaurs lived from 170 million to 65 million years ago.

4.

TERCIARY AGE: Continents continued to form from 65 million to 1.6 million years ago.

As well as appears: - mountain chains - Mammals - Early ancestors of human beings, called hominids, in Africa, over 2 million years ago.

5. QUATERNARY AGE: Last 2 million the Northern Hemisphere was covered by ice.

Human beings have exited for about 200,000 years.