Actually, evolution has been observed, both directly and indirectly. For example, there was a factory in Japan that produced nylon, a man-made material that appeared in the 20th century. There were bacteria found there that produce nylonase, a protein that digests nylon.
So which is more likely? The bacteria evolved this ability, or God gave them the ability to do so?
And as for indirect observation, we can see evolution in the fossil record, and even more importantly, in the genetic code.
There's plenty of evidence for evolution, you just need to look at it.