It is estimated that well over 99 percent of all the organisms that have ever lived have died without having had offspring. And yet here you are: of all your billions of ancestors over the years, from single cells to worms to fish to reptiles to mammals to primates, not a single one of them died childless. How lucky you are! Of course every blade of grass has an equally long and proud heritage, and every mosquito, and every elephant and every daisy.