Report: Abundant oxygen does not necessarily lead to the evolution of advanced life

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/French research team, led by University 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.