DJW: I think it is strange that the Bible says "The wages of sin is death" since every multi-cellular organism on Earth dies (not just humans), even plants, but plants don't sin. Right?
That does bring up some interesting questions. We can presume that the phrase was meant to apply to humans, who have a special relationship with God. So the question is, did non-humans always have a finite lifespan? Or did God decide that, if humans couldn't live forever, neither would any other life? God did not hesitate to include all non-human life when he caused the worldwide flood, aside from those collected by the humans He chose to save (some of which were sacrificed shortly after the end of the flood). So He did not seem to have the same concern at that time as He would be credited with later by Jesus (ie, the sparrows and the lilies of the field).