Chapter 25.2, Problem 2LO

Summary Introduction

To describe: The key steps essential for the origination of life.

Introduction: An uncontrollably dynamic environment, which shifts between a frozen and fiery Earth, was implausible to have supported life forms. The early atmosphere of Earth was comprised of CO₂ at high levels and it affected the temperature. Over 2 million years, Earth cooled forming silicate clouds. These clouds condensed and rained down, thereby forming the ocean. The level of CO₂ in the atmosphere decreased and Earth cooled further. Several times in the history of Earth, all the continents formed a single supercontinent. Over geological time continents moved, and in the Archean eon that followed the first Hadean eon, life forms emerged.