Some interesting facts from Bill Bryson's A Short History of Nearly Everything:

"The average species on Earth lasts for only about four million years, so if you wish to be around for billions of years, you must be as fickle as the atoms that made you. You must be prepared to change everything about yourself - shape, size, color, species affiliation, everything -- and to do so repeatedly[...]Not only have you been lucky enough to be attached since time immemorial to a favored evolutionary line, but you have also been extremely -- make that miraculously -- fortunate in your ancestry. Consider the fact that for 3.8 billion years, a period of time older than the Earth's mountains and rivers and oceans, every one of your forebears on both sides has been attractive enough to find a mate, healthy enough to reproduce, and sufficiently blessed by fate and circumstances to live long enough to do so. Not one of your pertinent ancestors was squashed, devoured, drowned, starved, stranded, stuck fast, untimely wounded, or otherwise deflected from its life's quest of delivering a tiny charge of genetic material to the right partner at the right moment in order to perpetuate the only possible sequence of hereditary combinations that could result -- eventually, astoundingly, and all too briefly -- in you" (pp.3-4).

"[Atoms] are also fantastically durable[...]Every atom you possess has almost certainly passed through several stars and been part of millions of organisms on its way to becoming you. We are each so atomically numerous and so vigorously recycled at death that a significant number of our atoms -- up to a billion for each of us, it has been suggested -- probably once belonged to Shakespeare. A billion more each came from Buddha and Genghis Khan and Beethoven, and any other historical figure you care to name. (The personages have to be historical, apparently, as it takes the atoms some decades to become thoroughly redistributed; however much you may wish it, you are not yet one with Elvis Presley)" (p.134).

"When two objects come together in the real world -- billiard balls are most often used for illustration -- they don't actually strike each other. 'Rather,' as Timothy Ferris explains, 'the negatively charged fields of the two balls repel each other...were it not for their electrical charges they could, like galaxies, pass right through each other unscathed.' When you sit in a chair, you are not actually sitting there, but levitating above it at a height of one angstrom (a hundred millionth of a centimeter), your electrons and its electrons implacably opposed to any closer intimacy" (p.141).