I believe its a complex as is our creation. Evo's hide behind micro evolution such as slight changes in a bird's feathers or beaks and then extrapolate that to macro evolution for which there is little to no evidence. They prefer to argue it as a pacxkage deal - you swallow all of it because of evidence of micro evolution. Its the kind of sophistry game democrats play.
The terms "micro-evolution" and "macro-evolution" are pure inventions of the creationists. No such distinction exists in science. There is ONLY "evolution".
It is difficult for humans to comprehend things that exceed their lifetime. That is why we have written history, art---and religion: an attempt to give the next generation the wisdom of the preceding ones. Evolution is one of those things. The so-called fossil record is one pinpoint in the story, completely incapable of explaining by itself the minute, step-by-step changes that have vanished and left no record.