CONTENTS INTRODUCTION CHAPTER 1 EARTH s ORIGINS 10 CHAPTER 2 THE BEGINNINGS OF LIFE CHAPTER 3 PALEOzoic ERA CHAPTER 4 Mesozoic ERA 48 CHAPTER 5 CENozoic ERA 62 CHAPTER 6 THE FUTURE OF EARTH 69 75 77 CONCLUSION GoSSARY For MORE INFORMATION BIBLIOGRAPHY 79 83 84 INDEX
INTRODUCTION 6 very day we walk across its surface admiring its variety of plants animals and landscapes Earth has taken billions of years to evolve into the planet we now inhabit This volume exam ines this long history from Earth's origins in a cloud of gas and dust to its place as a planet teeming with life It addresses questions that scientists have long debated how why and when did Earth form and develop into this complex and intriguing planet sts believe that Earth as well as the rest of the solar system began to form about 4 6 billion years ago from a gas and dust cloud called a nebula Under the force of gravity the nebula's particles came together to form objects that grew larger and larger eventually forming the planets At first Earth's surface was unstable covered with seas of molten rock As the surface cooled the crust Earth s solid outer layer began to form No one knows when the first crust formed though scien tists have generally dated the oldest rocks to about 4 billion years ago discoveries of some older miner als have led some to believe that stable crust existed hundreds of millions of years earlier To help study Earth's history scientists have devised a scale of geologic time The scale provides a framework for studying the evolution of the con tinents oceans atmosphere and biosphere the
Investigating the History of Earth
Much of the plant and animal life that seems so common now evolved relatively recently on the timeline of Earth’s long history.
About This Book
By: Michael Anderson
Illustrated by:
Published by: Rosen Publishing provided by Britannica
