This very important verse conveys several vital truths. First of all, death came into the world only when sin came into the world. Suffering and death of conscious life, whether animal or human, were not a part of God's "finished" and "very good" creation (Genesis 1:31 - 2:3). There was an abundance of food and all other provisions for both people and animals. There was certainly no "struggle for existence" or "survival of the fittest," for every creature was created "fit" for its own environment.
When Adam sinned, however, it became necessary for God to bring the curse of decay and death not only upon Adam, but also upon all his dominion (Genesis 3:17-20; see also Romans 8:20-22; 1 Corinthians 15:21-22).
Furthermore, there remains no warrant for the notion that "Adam" is simply a generic term representing the human race. He was "one man." In fact, he was "the first man" (1 Corinthians 15:45), and Eve was "the mother of all living" (Genesis 3:20). There was certainly no population of evolving hominids becoming "Adam." In fact, Christ Himself made it clear that Adam and Eve were there "from the beginning of the creation" (Mark 10:6, quoting Genesis 1:27).
The entire argument here in Romans 5:12-21 becomes irrelevant if the Genesis record of the creation and Fall of Adam did not happen precisely as recorded in Genesis 1-3, and this would mean that there is no reality in the saving work of Christ, either.
Such a rejection of the Christian faith is hardly warranted by the fragmentary fossils that have been alleged to support the notion of human evolution. No one should stake his eternal soul on such a will-o'-the-wisp as that! HMM http://www.icr.org/article/5988/