I've been rereading one of my favorite books, Panati's Extraordinary Endings of Practically Everything and Everybody. It's all about death, and here's what it says about the origin of death:

"Life on earth did not always end in death. . . From a biological standpoint, death, as we view it, is a relatively upper rung on the evolutionary ladder. And the single activity that mandated bodily extinction for each and every one of us was the advent of sexual reproduction. To state it bluntly: Bodily death is the price we pay for the distinction and advantage of sexual mating.

To backtrack 4 billion years. In the beginning, not all living creatures died. Few did. Some still don't. An amoeba, for example, need never die; it need not even, like the proverbial general, fade away. An "aged" amoeba late in life divides to become two "young" amoebas. Not much fun, perhaps, but there is no death, no corpse. Just offspring, a single parent living as its progeny. This is, of course, asexual reproduction. The amoeba has no sex life to speak of, but as compensation it is granted a long, long life indeed. . .

That was the case for life on Earth for billions of years. We trudge far through the evolutionary battlefield before encountering the first authentic corpse, the unmistakable evidence for bodily death.

When does death first appear?

If we take the estimate that life began on Earth about 4 billion years ago-that genes emerged 3.9 billion years ago, bacteria 3.8 billion years ago, viruses 1.3 billion years ago-then death-and sex-arrived on the scene as companions as recently as 1 billion years ago. It is around this time that "parents", in the form of a "mother" and "father", came together in the activity of sexual reproduction. They produced offspring, and having served their function, died off, each leaving behind a telltale corpse, evidence of a sex life."

The upshot of all this is that I'm apparently going to live for a very long time.