On original sin

The fall of man, or original sin (peccatum originale originans) as one might call it, is not so much a chronological state or phase but rather an ontological moment in nature as man experiences it. Therefore, the account of the natural sciences might not show any differences between the time before man and with man: it's just beyond their scope, and rightly so - they don't need to be concerned with that kind of question.

On a side note, one should also distinguish between natural desasters, diseases or consumption within the animal world, and cruel, immoral or sinful behaviour in the human world. A lion is not "evil" for eating the antelope, the eagle is not "immoral"  when he hunts the gopher, and the crocodile doesn't "sin" by devouring the gnu. It's just what they do. Man, however, has the ability to reflect on his behaviour, to distinguish between good and bad (or evil) - in other words: man can go beyond or against his nature, other animals can't.

Now this is highly speculative, but I'd wager that becoming and decaying - thus, birth and death in the broad sense - were part of nature before the Fall. The difference made by sin would be in relation to God's "will of history", to borrow from Aquinas. Before sin, the whole of nature and natural history went according to God's will, and man accepted it for what it was. After sin, God's will of history is untainted and fully intact, but man challenges it for he tends to substitute God's will with his own (or claim sovereignty over the categories of good and evil).

I wouldn't go as far as saying that pain and destruction were necessarily "good" things before the Fall. Yet, they were embedded in a salvific context, within the communion of God and man. Sin put away with this salvific context and dissolved this communion on behalf of man. That's where pain and destruction became deadly in the spiritual sense, which is the whole tragedy of sin.

What I mean by the chronological state as opposed to the ontological moment is a distinction between different disciplines of scientific or reasonable thought: A chronological state would be something occurring during the process of natural history, like e.g. the Cretaceous age. It is a reality in its own right, but not (necessarily) something which the biblical account is concerned with. Quite the opposite, the Bible is rather interested in the ontological sphere, it is a theological reflection. An ontological moment is something that occurs before the process of natural history kicks in; not as a starting point or some kind of initial instance, but as a necessary pre-condition. Following the Italian 17th century scholar Giambattista Vico, whose train of thought reaches up until contemporary hermeneutics, I'd say that nature can only be recognised by the human mind if it is mediated through history - human history, that is. Which means to say: To recognise nature, we necessarily have to take into account the aforementioned tragedy. Not as a natural cause among others, mind you - so, not alongside the shift of alleles or the likes. It's rather a reflective knowledge as regards the conditions of human knowledge. So, to every knowledge - scientia - we have to consider "with-knowledge" -- con-scientia -, which is where (the) "conscience" stems from.

Now, the salvific context concerns salvation, which is communion with God. It's a somewhat wholesome perspective, taking into account the "bigger picture", if that makes sense, i.e. the relation to God or the divine. For example, in historiography the salvific context would be to pose an event against the backdrop of God's commandments or to look at it as though it were an icon of something described in the Bible. So, if man challenges God's will by virtue of his own positioning of good and evil, this context is at least superimposed, but effectively cut off.