Think of life as a game. You make a copy you win. If you die before that, you lose.If you don't care to play only those that do will stay in the game and will eventually become the only living things. If you don't change with time then another player that does will sooner or later drive you to extinction. That's why we now have male and female. It allows for variation without mutation, you just mix and match genes that have already won in the test of time. You get new players every generation that have a chance on having a useful combination.
Life from non life. How did that happen? In order to answer that question you first have to define just what life is. My simple definition is self -replicating information. On the basis of this I make the claim that a new form of life has already been created by man, and it was created accidentally at that! ( By accident I mean that making a life form was not part of the intention to create it, it was man made for an entirely different reason but it just so happens it fits my definition of alive ) What is this brand new life form ? The computer virus , and I hope the dirt bags who make these annoyances never figure out how to make one as "clever" as its biological equivalent! As for how nature created the first life form I predict Saturn's moon Titan will someday yield some very important clues.
"Think of life as a game. You make a copy you win. If you die before that, you lose."
Where does that come from? It matters. Why would a single celled organism go to the trouble to reproduce? Okay, so over the course of millions of years and trials and errors, the thing has RNA that reacts to certain chemical excesses and initiates a complex reaction which results in two cells instead of one.
Why do the two cells band together? They're supposed to compete with each other.