Today was one of those days where walking out the door seemed to be a big chore.
Even though I was going to use my truck instead of my wife's car, I looked for the key to her car. It was not where I usually put it by the back door and it wasn't in my pocket with my truck and house keys. I gathered up my backpack and coffee mug, got the garage door key between my fingers and headed out.
Next bad thing: the key wouldn't go in the lock. It was frozen again from a recent rain. Back to the house to get hot water. Decisions: heat water on the stove in the tea kettle or a bit in a cup in the microwave. I started both and took the cup.
Pour water on door handle and set cup down. Key goes in slot and turns. Hurray! Set keys on hood of truck and put pack behind seat. Check car for my key. No luck. Take cup back to house and turn off stove. Back to truck, pick up keys off hood, open overhead door, back out, and get on my way.
Fret all morning about where key to my wife's car is. Could it be at friends' house where we went to a party yesterday afternoon? My wife got to the car first when we left, started it, and then sat on passenger side. Could I have dropped the key in the friends' drive?
We next went to a drugstore to buy a few items. Could I have set the key down on the counter? I've done that many times. My wife stayed in the car and listened to the radio. Did I drop my keys when I automatically reached for them before getting in the car with her keys already in the ignition?
After I came back from this morning's trip, I spent many odd minutes looking in various pockets and under things in the bedroom. The key could have fallen out of my pocket when I took my pants off last night or this morning as I put them on. No luck.
Mid-afternoon I decided to start a fire. After I had it going, I went out to get another load of wood. But as I did so, I carefully looked along the sidewalk to the garage. When we came home yesterday, my wife was first to the back door but hadn't got her keys out. I had reached in my pocket to get mine. Could I have dropped the key to her car when I did so? What do you know, there it was two-thirds the way to the garage, about two inches from the sidewalk and in the grass.
Think of all the things that could have gone "better" or "worse", relative to the loss of the key. If we had gone earlier to the party or not at all, other events might not have happened. Same for going to the drugstore. If my wife hadn't started the car or had come into the drugstore. If we had had more snow and the key was covered. If I had drunk or eaten more or less at the party.
Now think of the poor DNA replicating itself. All those molecules strung in that double helix. What if some necessary chemical is not present? What if some contaminant is present? What if the radiation level or temperature is higher or lower? DNA is replicated not in a "clean lab" but in an uncontrolled environment, an environment that varies widely as the carrier of the DNA goes about its business. Just think of the varying stress levels of my morning, stress causing the chemical composition of my body to change to compensate for my stress.
As these various "random" events could have a larger impact on my life, like just writing about it, so could "random" events change how DNA was replicated. Some of the changes could lead to failure of the organism, others could lead to a even better fit into the general environment of the organism.
