Reply to Vast
If the auto-catalytic loop based theory is right, then there is a continuum between ordinary chemical reactions and life, and life is constantly evolving all the time de-novo, in every area where chemical reactions occur, but it will almost always fail due to a paucity of complexity in the environment, and ultimately from competion with more sophiphisticated (already evolved) organisms as discussed above.
Brief explanation of my version of the auto-catalytic loop theory:
Imagine a chemical soup in a fixed size container with many different compounds in it (ideally including carbon, hydrogen, oxygen, nitrogen).
Map the chemicals in the soup into a conceptual 3-d array, so each unique element or compound has a spot in the array.
Within the soup, each chemical has electric fields around it, and these fields influence the probability of chemical reactions taking place in it's vicinity, usually by a very small amount, but in a few case (as in a catalytic reaction between nearby molecules) by a lot.
Thus every chemical in the soup influences the rate of formation of every other chemical in the soup, although usually by a very very small amount. The influence may be positive or negative, and varies dramatically by distance.
We can represent the influence of one chemical on the rate of formation of another by a line on the map. If the influence is negative, we can color the line red, and if it is positive we can colour the line green. We can make the thickness of the line represent the strength of the influence. Most lines will be almost infinitely faint, but a small proportion will be clearer.
Now the key part: some green lines will form loops. For example where chemical (A) increases the rate of formation of chemical (B) which influences the formation of chemical (C) which increases the formation of chemical (A) again, in a closed loop.
Each loop is a positive feebback loop, only limited by the resources available and competition for those resources from other green loops.
(Red loops also form, but these are negative feedback loops, and not so interesting).
So as time progresses in the soup, molecules which co-operate by assisting each others formation via green loops will tend to become dominant in the soup, because they will "out-compete" other molecules that are not components of green loops. Molecules in red loops will become less common. Simpler elements and chemicals will tend to disappear (get used up).
Thus the soup provides reproduction (of specific molecules) and competition (for raw materials).
One more key item: often green loops will have alternate pathways, in other words they will not be simple loops, but will have branches via other compouns that mean the loop is actually a set of branching loops which overlap and rejoin in complex ways. As one specific chemical resource is depleted, loops will tend to operate via alternate pathways that use different resources. So the loops almost have an existence of their own.
Also, different loops can form cooperative loops with one another, in super-loops.
Since a molecule's effect on other molecules in the soup is much greater when they are closer together, there is an incentive to evolves so different molecules are somehow held together in a more concentrated soups, so some sort of 'bag' to keep sets of co-operating molecules together would be a very effective way to beat the competition. Thus single celled organisms evolve, but clearly a lot needs to happen before that can take place.
The beauty of this understanding is that is automatically creates life as a co-operative set of intereacting molecules of different types right from the start. There is no need to worry about whether the first life bas RNA-based, Sugar based or Lipid-based. By this theory it _starts_ as a co-operating mixture and carries on from there.
Another deduction that can be made form this theory is that this simplest of all life is happening all the time whenever chemicals can interact.
You could argue that it is not life, but you can't really argue that it does not lead smoothly and continuously to life, so where is the dividing line? - we have reproduction, competition and variation, essential ingredients, we even have an ecosystem.
Another important deduction, life will eveolve automatically and naturally whenever an appropriate environment is present, and it starts immediately. Thus we would expect to find life in every feasible environment in the universe. It is simply a question of how sophisticated and complex it has become in that environment.
