I believe that both coexist.
I am very interested in how life started. I was just reading an article about the possibility of life on other planets, and how they once thought conditions had to be near perfect for life...but after discovering life in very hot or cold conditions on earth, they are changing their theories on where exactly life could exist in the universe, the possibilities have broadened. But still, how does life start? There is still so, so much to learn about life and evolution. We have learned just recently that there were many different early human families, unrelated. It's not a direct line like they once thought.