Someone was saying that randomness was a big part of molecular biology. I responded that it may be less than we think because these random changes must happen in a non random environment. Specifically a temperature range that only allows for chemistry at that temperature. Let's go further with 2 examples. Let's say you have a beaker that heats up from 50 C for 5 hours, then lowers for 5. And repeats endlessly. There may be random molecular changes, but they will be within the chemistry of that temperature range. And the variants from say the fluctuating temp on the edge of a star, would be random too, but they too would not exceed the reasonable bounds of the chemistry of temperature in that range. Thus random changes must exist within the non random chemistry boundaries of that environment. So there is randomness - but it is far from open ended randomness. It has strict boundaries in that randomness.