My apologies, I have since expanded that post so I'll repeat the addition here -That's molecules interacting everywhere, throughout time.
What programmes molecules to interact? How is their behaviour maintained throughout time?
Take carbon and oxygen, they can combine to form two compounds, carbon dioxide and carbon monoxide, one is far more stable than the other and so will prevail. Carbon monoxide, when in the presence of oxygen, will react to produce the more stable compound, a very simple pattern has been created.
The huge step was when compounds eventually formed that were able to replicate themselves. After that it was a matter of those that were best able to survive and replicate were the ones which won out. One method of survival was to exploit new niches, that required added complexity, but that came with the passing of the years. Now, whether evolution is purely a matter of Darwin's survival of the fittest is an open question, but I think the basic principle is sound enough. And yes, I am in total awe of evolution and feel there is more to natuarl selection than we have yet discovered.