Unplanned and highly contingent
The last time I was out with the camera my subjects were some unusual ice formations and, when I wrote about them, I elected not to offer a mechanism for their development. I will correct that, now. The days which preceded the day on which the photos were taken were quite cold, and the intervening nights were even colder. Average temperatures for the three days before I recorded the images ranged below zero. Winds during the period were calm and precipitation came as 0.05″ of snow. I think it is fair to say that the days preceding the day the images were taken were very cold, still, and dry and I would argue that the co-occurrence of these conditions lead to the fortuitous formation of the intricate ice patterns. Let’s take January 1 as the start date for a thought experiment. I can add an end date as well, since we had very moderate temperatures and 0.5″ of rain on January 10. So, on January 1 the water in our stream was at a particular level. Because it was quite cold, ice crystals began to form at nucleation sites at the interface between air and water. Once crystals began to grow, they continued to do so by accretion. Now, imagine that the water in the run drops just a bit, especially during the day when perhaps some evaporation may occur and when, at the same time, liquid water is drawn deeper into the soil by a range of biological activities. With the water level just a bit lower, ice crystals will continue to accumulate, but lower down. Because the level of water in the stream drops only slowly, the successive icy plateaus can be smoothly connected. Eventually the elaborate pattern emerges. By the tenth of the month everything is erased by rising temperatures and falling rain. As I’ve said, just the right conditions were necessary for these patterns to occur and, as I walked the run yesterday, nothing like the formations I saw two weeks ago, were in evidence. Soon after I posted the ice images, I responded to a comment made by Shoreacres with the following, “This is taken from Richard Dawkins (The Blind Watchmaker) … If you walk up and down a pebbly beach, you will notice that the pebbles are not arranged at random. The smaller pebbles typically tend to be found in segregated zones running along the length of the beach, the larger ones in different zones or stripes. The pebbles have been sorted, arranged, selected. A tribe living near the shore might wonder at this evidence of sorting or arrangement in the world, and might develop a myth to account for it, perhaps attributing it to a Great Spirit in the sky with a tidy mind and a sense of order. We might give a superior smile at such a superstitious notion, and explain that the arranging was really done by the blind forces of physics, in this case the action of waves. The waves have no purposes and no intentions, no tidy mind, no mind at all. They just energetically throw the pebbles around, and big pebbles and small pebbles respond differently to this treatment so they end up at different levels of the beach. A small amount of order has come out of disorder, and no mind planned it. I like this description of how order may arise from disorder and play games with our [mostly visual] senses.” To close, let me point out another series of concentric rings, this time as they were observed on a Bracket Fungus, just yesterday. The cause of the repeated sequence you see is no more due to happenstance than is the rising and setting of the sun. These are annual growth rings and, like those that may be observed in a felled tree, represent alternating periods of rapid (light bands) and of slower growth (darker bands) of the individual. So, what’s the point of all of this? Just that, as organisms, we are programmed to see and to react to patterns in our environment. Some of nature’s patterns occur entirely by happenstance while others occur for reasons which are just the opposite. How’s one to know? By learning to read nature, that’s how.