I believe Earth is too meticulous and perfect (prior to human interference) to be merely coincidental/accidental. Not saying a 'big bang' never happened, but there has to be more to it than that. Something as simple as growing a plant is almost magical -- must be the perfect climate, right soil, right amount of light (Sun v Moon), right amount of fresh water (how does a plant in the middle of a forest get water? Oh, right, rain - water that magically falls from the sky on occasion.) And, oh yea, all plants require different amounts of these things in different climates and areas. And then those plants provide food so that other life can thrive.

However, I'm also not religious, so I do not believe everything was created by one being, definitely not a being of the human image. I believe the truth lies somewhere in between. I believe it all has to do with energy, biology, and maybe a small amount of creation/interference to some degree-- we just don't understand much more than that, yet, but we so desperately want to, so we try to fit these unknown things into boxes that we do understand and it just doesn't fit...yet. I'm comfortable NOT believing any of the existing theories (at least as "complete" theories) and I find it funny when people argue or get heated about one or the other as though they are 100% certain.

My theory (just for fun, obviously not a scientist) is that Earth was likely discovered and developed by several different advanced races originally wanting to inhabit it for resources.
At some point, for some reason, it didn't go as planned (maybe floods? (Atlantis) maybe climate? maybe war? maybe they just found a better place?) and all of those civilizations abandoned it, leaving humans here to fend for themselves with the existing flora and fauna. Created, or maybe brought here, as a slave race to help with development, they didn't really care what happened to us humans, left behind like abandoned pets. Being slightly more intelligent than the rest of life on Earth, we found a way... and here we are constantly looking for this higher meaning, the how and why.

Theory sponsored by too much Rick & Morty, History channel, and blue mushrooms.