I am here today because of an unbroken line of ancestors that reaches from the earliest mammals all the way to me today. More specifically, and astonishingly, I am alive today because:

• None of my ancestors ever decided not to have any children.
• None of my maternal ancestors ever miscarried or aborted any of my ancestors.
• Every one of my ancestors lived long enough to grow to adulthood and procreate before getting killed by disease, war, accidents or old age.
• Each sexual intercourse of all my ancestors resulted in a sperm actually reaching the egg, and the exact sperm that reached the egg was critical for me to be here today. Of those millions of generations of ancestors, any one different sperm, and I would not be I today – and I would probably not exist.
• If any of the sperms just in the last 100,000 generations of hominid ancestors I have had carried an X instead of a Y chromosome, or the other way around, I would not be here today. The exact order in which it happened was necessary to make me possible.
• All the possible permutations of what could have happened count in the trillions, yet only this one permutation actually occurred, that is me today.

This line of thinking caused me to think back to the earliest primate we know about, the purgatorius that lived about 65 million years ago.

The purgatorius is believed to be the earliest example of a primate or a proto-primate. It was a small rat-like mammal, about five to fifteen inches long and lived in borrows underground about 65 million years ago. When the dinosaurs became rapidly extinct around that time, a niche opened up for mammals. Some scientists speculate that the purgatorius, due to its primate-like teeth, may be the most distant ancestor of all primates. Over time more advanced primates evolved from the purgatorius: monkeys, apes, and eventually, 63 million years later, some hominids started walking upright in East Africa.

So there was a rat-like primate that looked like a rodent, which burrowed in mountains of dinosaur dung for beetles and worms 65 million years ago that had a litter of babies, at least one of which survived to have its own litter, and so on, and some twenty million generations later here I am…

…typing this up.