Bird Poop and the Origin of Life

I’ve owned some form of bicycle or other for 34 years. I had never had the small misfortune of having it decorated with bird droppings. If you polled people, you would probably learn that they too, for the most part, have been spared of this unpleasantry. Bikes, in general, are not used as frequently as cars, especially in our inclement weather, and they are also thin, making it less likely for their frame and tires to become landing receptacles for that unique combination of uric acid and feces.

And yet that’s exactly what happened to me this morning. After a half-hour stay in the park with my son, the guck was all over my fender, handle bars, brake and gear wires. It was a reminder of the fact that an increasing number of unlikely events are experienced with age. As time plays itself out, events with low probabilities are more likely to materialize. An event that has shown to be 95%-failproof over the course of one year’s use (like a condom, for example), if used for a period of six years, becomes only (0.95)⁶ = 0.74 = 74 % failproof. Subject to these same laws are even more vital processes, such as aging and the origin of life itself.

Our DNA’s basic units constantly undergo molecular damage, and luckily they are repaired by a very efficient system to maintain the integrity of our genetic code. But “very efficient” is not equivalent to perfection, and with time, everything from wrinkles to cancer appear. Even when there were no oxygen molecules or microorganisms to break up large molecules, it was unlikely for them to spontaneously evolve into a self-replicating system. But the earth has been around for 4.5 billion years. Life only appeared 0.5 to 1 billion years later. With that kind of time on their hands (or bonds, I should say), molecules experienced events far more momentous than the poop that landed on my bike.