Origin of Life: early land life (Introduction)

by David Turell , Tuesday, July 23, 2013, 18:16 (4142 days ago) @ Balance_Maintained

Tony: If life existed 2.2-2.8byn ago, why did large life only crop up in the last tiny fraction of that time?-Actually borderline evidence of bacterial life goes back to 3.6 billion years ago with definite evidence at 3.4 billion years ago. What is described in the article are more complex organisms. Why complex life waited to the Cambrian is an unknown, except that oxygen began to really increase in concentration. It was miniscule when Earth formed and only 5% for much of the time. Now it is 21%. Remember oxygen is a dangerous substance (as any forest fire will tell you) , and living bodies need antioxident controls at all times. My guess is that the complexities of using oxygen to burn fuel took evolution a long time to sort out the controls. Remember I believe in a God-designed evolutionary system that was left to work out complexity much of the time on its own.