if life has evolved, from what did it evolve
This is like looking at an IBM mainframe and asking the same question.

There is no single easy answer. The answer lies somewhere in "it all sort of came together after lots and lots and lots of trail and error (where trail and error on the part of nature is purely non-directed)"

Thinking that it all had to have a single beginning doesn't make sense. Another example is saying where is the beginning of the Mona Lisa painting. There is no simple beginning.

DaveS - you are trying to apply linear action->result->action->result thinking. You can't use this sort of logic in this situation because it did not follow a linear development path. A more appropriate thought process would be to use fuzzy logic combined with probability theory.