 |
 |
|
 |
 |
Thermodynamical models of evolution - Entropy
At a certain point in his important article on Evolution, Entropy and Work, James Fournier states that "it became possible to hypothesize that in strictly thermodynamical terms living systems are the work extracted from the energy flux across the potential", which is essentially the same thing Schroedinger said decades ago (read here: "What is Life - Entropy"). But how can an organism "maintain itself stationary at a fair level of orderliness (= fairly low level of entropy)"? Fournier indicates that when humans build machines we mimick what Nature does, "at least in so far as we are faced with the similar constraints as those facing any other organisms attempting to further their own survival". He reasons that we need only look at the most basic thermodynamics of the situation to see that the problem, both for humans and for other organisms, has always been how to extract as much useful work from a potential energy gradient as possible. Then comes the important part: there are two ways to do this. One is to increase the magnitude of energy flow across the gradient. The other is to increase the (thermodynamic) efficiency of its use, that is, maximize the work extracted and therefore, by definition, minimize the entropy production. He proceeds: "The first approach can lead to increased entropy production, if the thermodynamic efficiency of the process remais constant. But the second approach, which incidentally seems to be highly optimized in natural systems, may actually lead to a reduction in the entropy increase". Some expositions about the second approach follow: the thought experiment of the Benard Cell, photosynthesis and respiration, the thermodynamical behavior of the planet as a whole, with the transition to life through the evolution of photosynthesizing organisms, and the anti-climactic but inevitable human use of fire, which increased the overall rate of entropy on Earth. "What a piece of work is a man!
How noble in reason! How infinite in faculty! And tomorrow we can proceed to "Molecular Nanotechnology - Entropy". Related news:
|
|
