Introduction

 4.6 billion years ago,in a corner of the universe,the earth came into earth came into existence.Upon its birth,it was a lifeless planet completely covered with fluid magma and vapor.Since the ozone layer had not yet been formed at that time,harmful ultraviolet radiation from the sun poured directly to the surface of the earth.

 Slowly as the temperature of the magma fell,the earth's atmosphere cooled and the vapor turned into water.The rain poured onto the ground,and formed the oceans that cover the earth.The first forms of life on earth emerged in the seas and these produced the oxygen of the atmosphere.The ozone layer,which is only 3mm thick (at atmospheric pressure),was formed over a period of more than 2 billion years. Only then,was it possible for life to survive on the ground.

 The first species that appear ed on the ground were plants.Due to the oxygen released by these plants,the atmosphere reached a point of balance that allowed more advanced forms of life to appear on the earth.After this,gigantic dinosauls and plants flourised over the earth.The earth came to be a "Planet of Life"

 About 63 million years after the extinction of the dinosaurs,the humanrace appeared.Making use of their inteligence,humans developed various types of technology and social systems to make their lives more comfortable and convenient.Since the industrial revolution of about 200 years ago,human life has been increasingly based production and mass consumption.

 Right now,we face with serious environmental problems such as destruction of the ozone layer,global warning and desertification.And the huge quantily of products modern technology have resulted in a serious waste problem and chemical pollution that influences even our genes.

 Now we need to reflect seriously on the 4.6 billion-year history of our planet earth - and its future.