I've been pondering this for a few months now, and I have spoken with some of my more well-read YEC friends and haven't found any answers that satisfy me yet. My thought process goes something like this:
1. If God created every animal and plant as a product of special creation, then they were created in their current form ~6,000 years ago with no change in structures.
2. This means that God created predators with dentition and a digestive system specialized for consuming meat. These specializations would not have been needed in the garden.
This means one of three things:
1. After the fall, God stepped in and did more acts of special creation to alter certain animals to be predators in the new fallen world.
2. Those structures were put there from the beginning because God knew man would disobey.
3. There is some biological mechanism that can produce changes in the structure of animals (i.e. mutations + selection).
I don't buy number two, because I feel like it's a cop out. Do you all have any thoughts on predators existing before the fall?
Changes are implied when God laid down several curses. I would say #1 certainly has to be true to an extent, as there are explicit changes mentioned.
Now that doesn't mean He didn't also anticipate some things, and therefore put some defense-attack systems in place, but this seems unlikely to me. For the following biological and material changes for certain took place:
1) Physical death - All humans and animals began physically dying. There most certainly have to be a change made in all species for this to happen. Whatever it was, it was not there in the beginning when God declared everything to be good.
2) Snakes (nachash) were physically changed. This is an explicit fact. How they were changed cannot be known for certain, but a change took place that affect their locomotion. The removing of their legs seems implied as that's the only thing that seems to fit.
3) Other animals were cursed and by implication also changed. "
Cursed are you more than all cattle, And more than every beast of the field;" The implication is others were cursed and changed as the snake, but to a lesser degree or in a way that was less symbolically humiliating.
4) Pain in childbirth. This is also a physical change. Pain in general perhaps was new as well, but pain in childbirth was not part of the original design. Now by implication, this also extended to some mammals as some of them also experience pain giving birth—some a great deal of pain! This also must have been brought about by a modification of God after the curse.
5) Attitude changes in women and in men. The woman was to start having the desire to control her husband as part of the Curse. Why, what changed? Perhaps something in the brain, but this was not part of her original created tendencies. By implication animals also must have been changed in there area, as they also can be quite hostile to the opposite gender of their own kind.
6) Thorns and Thistles added to plants. Yet another explicit change. These are obvious defense systems that were not part of the original design. Now some plants would have sharp piercing protrusions coming out of them. Some animals have these as well, and it's a reasonable inference they received theirs at the time of the curse as well.
7) Cursed is the ground. A change in the soil making it hard to grow crops Another explicit change. What exactly changed, we do not know, but the original soil was different. Something in it changed at the time of the Curse.
Now this doesn't rule out #2 completely, but it does support #1 to at least some degree. I just don't see the necessity of #2. Certainly God knew what was coming, but it seems more likely he would make all the changes He wanted at the time of the Curse since he was making changes then anyway.
Now number 3 also can come into play, but I highly doubt some of the major defense-attack-systems slowly developed. The changes mutations would cause would have to be more subtle, like perhaps Polar Bears losing the skin between their toes so their feet became webbed. Maybe elephants losing their long hair and things like that. But developing a quill in place of fur? That would seem to have to be design or modification of a design.
That's my 2¢
God already had a redemptive plan ready, should it prove necessary. That means at the very least he was thinking ahead of contingencies, should creation fall. Perhaps those contingencies were wide in scope.
