[by one man]
There is no warrant in the New Testament for the heretical notion that “Adam” is simply a generic term representing the human race. He was “one man,” in fact “the first man” (I Corinthians 15:45). There were no pre-Adamite men, as some have alleged, and certainly no population of evolving hominids becoming Adam. In fact, Christ Himself made it clear that Adam and Eve were “from the beginning of the creation” (Mark 10:6, quoting Genesis 1:27). Adam was a real person, directly created and made by God, and so was Eve. The entire argument of Romans 5:12-21 becomes irrelevant if the Genesis record of the creation and fall of Adam did not happen just as recorded in Genesis 1–3, and this would mean there is no reality in the saving work of Christ either. Destroying or distorting the plain Genesis record undermines and eventually destroys the gospel of salvation. Such a devastating undermining of the Christian faith is surely not warranted by the fragmentary and self-contradictory fossil evidences that have been alleged to support the notion of human evolution.
[death by sin]
Thus there was no death before sin entered the world. The finished creation was “very good” (Genesis 1:31), with an abundance of food and all other provisions for man and the 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, God brought the curse of decay and death not only upon Adam but also upon all His dominion (Genesis 3:17-19). See also I Corinthians 15:21-22; Romans 8:20-22.