Lots of Oxygen Doesn’t Always Lead to Evolution
Any textbook will tell you that oxygen is essential for advanced life to evolve. But why did life not explode when oxygen levels rose dramatically 2.1 billion years ago? This is the big question after a Danish, Swedish and French research team, led by Univ. of Southern Denmark, has shown that the oxygen content 2.1 billion years ago was probably the same as when life exploded 500 million years ago.
Oxygen and advanced life are inextricably linked. Some simple organisms like bacteria can survive without oxygen, but all higher organisms need oxygen and the Earth’s biology would probably be a poor sight, if the atmosphere did not contain the 21 percent oxygen, which is essential for the human brain to function.
Read more: http://www.laboratoryequipment.com/news/2013/10/lots-oxygen-doesnt-always-lead-evolution