Evolution answers the first question for me.
As to the second question," Nature has no purpose, it only has process" E.O. Wilson.
It doesn't really. While nature and reality might not have a meaning, humans still need meaning. What Nietzsche called "affirmative nihilism". We need to give life meaning to function. With a limited lifespan and a pretty insignificant footprint humans attempts to give life meaning is likely to be self agrandising.
You make the assumption that "We" need meaning to function. I and most people I have known just need to do what it takes to survive. As have most humans that ever lived. I have never been ambitious. But I have always been curious to know how the universe works. Talking about meaning is boring.
What's the point of surviving? There's no point avoiding to crash your car if there's no place you need to go, including where you are now.
Nature doesn't require us to need a meaning. It is something some people seek out. Human kind have no meaning. Our type of existence is a rare mathematical hiccup that is statistically very rare but destined to happen given enough time.
Whatever meaning life has is up to each individual. No one has the business telling someone else that their life has no meaning.
Those are two different statements. In nature, our lives have no meaning, FACT. We existed as a species for much longer before we made with civilization. No meaning to them... no meaning to us.
That doesn't mean our lives are meaningless, without purpose, etc... It is just from a nature standpoint, nada.