So if Genesis 1 describes a continuous, purposeful process, as those who understand ancient Hebrew suggest, and if the universe is beautifully designed with absolutely perfect and essential scientific constants for the existence of life as we know it, as those who understand the science suggest, what do I think happened in the Fall? My answer may be a little whimsical. It's not specifically Biblical or scientific; it's just my interpretation, and I offer it because I was asked to:
I image that Adam was one of many "first humans." Of all the humans then living, his genes were the ones that would be passed down to further generations--all other "families" would eventually die out, as indeed, we see families dying out around us all the time. God either saw or chose this, and took Adam to a place on earth where not only were the known scientific constants perfectly tuned, but so were all the ones we've never discovered (the ones that are no longer either perfect or constant). There Adam dwelled with God, married his wife, and lived in great harmony with nature. The lion lay down with the lamb, and the lamb died exactly when the lion needed to eat. Everything was in perfect ecological balance. But...
Well... imagine any of us in such a Paradise. Wouldn't we ask "What if we eat that fruit?" even though it was forbidden? Wouldn't we want to try "just once" whatever we'd been told we shouldn't do? And wouldn't we "accidentally" destroy that perfect balance, ending up with the world we have today?
That's my picture of the Fall. And in the New heaven and the New earth, one day we shall be made perfect and perfectly able to stick to the rules that make everything perfect.
Till then, I give thanks for salvation in the well-known and very historical Jesus Christ whose birth we celebrate soon.