Chistianity and Judaism stole plenty of their concepts from the people of the earliest known written religious material-namely Gilgamesh from the Sumarian civilization (modern day Iraq). In those writings you can find Noah and his ark, the legend of Adam and Eve, and a whole lot more-just different names-and ALL written well before any known copy of the Old Testament. The fact is that all religions are an evolving (or not) continuation of what came before.

The ancient Sumarians, Egyptians, Greeks and Romans were not stupid-their philosophical works show as much curiosity about life and death as we have today. The continuing efforts of many religions including christianity to say "my religion is the only religion" are a joke. Who knows when Christianity will be left behind for something new and better, yet dont be supised if aspects of it would also be present in the next generation of religion.