This finding would seem to contradict the basic idea behind an earlier study according to which life on Earth just had to evolve (but no one knows how, exactly):
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.
Note, by the way,
The development of life exploded around 542 million years ago during the so-called Cambrian explosion, … More.
Uh, um, yeah, that’s what it is so-called, the Cambrian explosion. – O’Leary for so-called News