Hiya!
I am not a scientist so I do bow to others superior knowledge on this site regarding these subjects (and welcome their input) but what is to stop these two theories both being proven so that they both apply to our origins.
Well, you can't prove the existance of god... or that god doesn't exist. Nor can you prove that the various creative myths in various cultures happened as they are described in the culture's Holy books/traditions -in fact, normally you can only prove that creation stories are very obviously not meant to be taken literally nowadays even if the writers took them literally.
One can equally say that the 'first cause' (i.e. what made the Big Ban bang) is non-provable by science. Likewise the theories as to the mechanism/s of evolution cannot generally be proved.
If you allow yourself to accept that god existed before the start of the Universe as we see it round us, then you can argue that god made it the way it is the way it seems it did; big bang, cosmological expansion, condensing of stars, systems, groups, galaxies and clusters, organic life developing from monocellular to us via a process of evolution. There's loads of evidence for the physical process of evolution.
Of course the 'allow yourself to accept that god existed before the start of the Universe as we see it' bit is good old fashion faith and unprovable.
Likewise, the latest "something out of 'nothing'" theories of cosmologists as to how the Big Band happened are essentailly, for the most of us, as understandable as the doctrine of the Trinity. Tricks with numbers we can't asses the accuracy of. Of course, when someone creates a small Universe in their laboratory, they will have proved them (and run up the largest electricity bill in the history of mankind). But that hasn't happened yet.
However, one can say 'why believe bronze age goatherds were so clued up as to how we came to be', and decide that god is NOT a creator, and that the scientists are probably right about most things, but that there is a 'god' anyway.
Not the Judaeo-Christo-Islamic dude we are encluturated into.
But EITHER something that started evolving a LONG time before we did and is keeping an eye (or whatever non-corporeal entities use for vison) on us, and an awful lot of people are hyping him and saying he'll do this and that and made this and that when it is just as much part of the physical Universe as you or I and is certainly not omniscient or omnipotent.
OR one can say god is comprised of everything and we are part of that everything. God becomes depersonalised, but is still there. You can even add ideas like 'the Univesral mind' giving arise to avatars such as Vishnu (blue Indian god-dude), Buhddah (chubby meditating dude) and Jesus (love-your-neighbour carpenter dude).
All of these are unprovable but at least don't have four thousand years of errant nonsence and primative beliefs clogging them up.
Personally I go between a depersonified god (if you get beneath the 'lots of silly gods' layer of the Vedic (Hindu) there are some suprisingly sensible ideas) that we are part of, and wondering why people bother.
I mean, it does have to be said WHY do we have to essentailly guess as to the nature of god? To me that either says god is playing silly games or there isn't one, as the only excuses for god not sitting on the end of our bed each night and leaving his omnipotent omnipresentness in no doubt are silly ones made up by humans, like the 'why no miracles now' excuse.
God not proving its existence to us when it is extremely reasonable to doubt its existence means either god is playing silly games, or there isn't one. And as the idea of a god playing silly games really is bronze age (Greeks, Romans, etc) is initself silly, I go for the 'no god' or the 'thou art god/I am god/that dog is god' model.
All the best
