According to the Apologetics Bible, and other sources I have read/heard, physical death hadn’t occurred until Adam/Eve sinned. I disagree because of the fossils that would have existed prior to Adam as well as Genesis 3:22; And the LORD God said, "The man has now become like one of us, knowing good and evil. He must not be allowed to reach out his hand and take also from the tree of life and eat, and live forever." It seems that physical death was already the norm. My thoughts are that the death referred to here was a spiritual death.
It is a common evangelical teaching that physical death did not happen on the earth until the sin of Eve and Adam. It is commonly taught in fundamentalist circles that even physical death of animals did not happen until the "fall" of man. Of course this belief is intimately tied to the young earth creationist doctrine. This doctrine is supposedly based on a literal understanding of both Genesis 1 and 2 and of Romans 5:12-14. In reality, I believe it is based not so much on Romans 5 as on the Augustinian doctrine of predestination/Original Sin. Romans 5:12-14 says "Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned–for before the law was given, sin was in the world. But sin is not taken into account where there is no law. Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a comand, as did Adam, who was a pattern of the one to come." Does this passage teach that animals did not die before the sin of Adam?
I believe that the death which reigned from the time of Adam to the time of Moses (Romans 5:14) was spiritual death. Apparently from your question, you have the same belief. Like it says in Romans 6:23, "The wages of sin are death, but the gift of God is eternal life in Christ Jesus." Both the life and the death here are spiritual, not physical. I believe we cannot prove that Adam and Eve would have lived physically forever if they had not sinned. In fact, I doubt very much that this is the case. It certainly is not taught in Romans 5. They did not die physically when they sinned, but they died spiritually. They lost their intimate relationship with God.
Bear in mind that the real motivation for this interpretation is the underlying theological assumption of total depravity and Original Sin. Calvinists believe that when Adam and Eve sinned, humans fell so far that they no longer have even the ability to respond to the love of God, to come to faith and to choose to accept salvation from God. This fall even affected irreversibly all animal life, according to many Calvinists. Only those predestined and prechosen by God can respond. The rest will be condemned. This false understanding of the result of the sin of Adam has resulted in other hyper-interpretation of Genesis 1-3 and Romans 5. It is a doctrine which denies free will.
I agree with your criticism of this false doctrine from a scientific perspective as well. Let us not worry about the age of the earth for a while. Let us even concede the possibility (no matter how obviously inconsistent with what seems obvious from scientific evidence) that the days of Genesis one are literal twenty-four hour periods. Does Genesis or Romans really teach that physical death was introduced to the world through the sin of Adam? What did God intend for lions to eat? If they were eating plants, their teeth are very poorly designed! What about praying mantises and tasmanian devils? WEre they eating plants? Death is as much a part of creation as life is. Physical death is not evil. Where in the Bible does it teach that physical death is evil? Where does it imply that it is evil for one animal to kill another? This teaching is not biblical, but it is the result of poor theology.
Now, let us consider scientific evidence. If the Apologetic Bible is right, then the fossil trilobytes from the Paleozoic Era (540-250 million years ago) and the dinosaur fossils from the Mesozoic Era (250-65 million years ago) never lived or died. The sedimentary layers, including an uncountable number of fossils of species which no longer live, is up to ten or even twenty thousand feet thick. Can we really believe that nothing on the earth died until just a few thousand years ago? This interpretation of Romans 5 and Genesis 1-3 is dificult to sustain, both for theological and scientific reasons.
As a personal side note, the editors of the Apologetics Bible once considered using me as an editor for their work. After a few positive discussions, suddenly their interested ended and they were not interested in talking to me. I got the strong feeling that this turn of events happened because they detected that I am not a Calvinist and that I believe baptism is an essential part of salvation. I may be wrong and you should take my speculation with a big grain of salt, but this may cause us to be a bit hesitant to assume that the editors of the Apologetics Bible are unbiased in their theology.