Transcript: In general, evolution proceeds from simple to more complex forms of life, but it’s not the unique and defining attribute of evolution. Simple organisms can be extremely well adapted. Anaerobic bacteria have survived on this planet for over three billion years. No large and complex creature has ever lived for more than a few tens of millions of years. Also, early life was not that much less complex than current large life forms. We share forty percent of our DNA with simple yeast. In the early history of the Earth, the complexity of DNA and the diversity of chemical reactions rose relatively quickly in the first few hundred million years of life, and it has not increased in complexity dramatically since then.