@DNA Thumbs drive,
go into the future on the ribbon of time for a moment, and see that humanity will leave the Earth, and this can not be possible unless it brings with it food and the entire ecosystem for food to form. Thus when we introduce even a simple photosynthetic algae to another place, say Mars or a moon of some other planet, then we have brought life to that place, and created the opportunity for evolution on another new World. Why do you not see that this is what we will do one day, soon or distant it does not matter, this will happen, and when it does, we have brought life and evolution to a new place. The day that you can say that this did not happen here, in the past will never come, because the future determines it's scientific logic.
Thus, while we do not know where life came from, we do know that we can not stay here and continue to exist as our planet and Sun are finite, and we do know that life will thus be leaving, to evolve in another place. Now this is interesting, because it makes the Earth not important, as it is just another place in an infinite universe, and because it gives humanity the power to populate a new World with life.
So get your ass out of the past, and start designing a new motor to get us all out of here, because the universe beckons with wonder.