Monday, August 11, 2008

Evolution as Described by the Second Law of Thermodynamics

In Part 2 of my "Imagination Without Knowledge Is Ignorance Waiting To Happen", I listed one of the most common argument that some creationists had tried to use (and some, still are using) to discredit evolution. They argued that the 2nd Law of Thermodynamics is "proof" that evolution is impossible.

Of course, these misguided people have no clue on basic physics, or they wouldn't be making stupid claims like that (thus, the "without knowledge" and "ignorance" connection). But now, we can go even a step further to the other side and show that, in fact, the 2nd law of thermodynamics CAN describe evolution, and that this aspect of physics is a necessary ingredient in how evolution proceeds! This is explained in a paper by Ville Kaila and Arto Annila of the University of Helsinki published in the Proceedings of The Royal Society A.

The second law of thermodynamics, which states that the energy of a system tends to even itself out with its surroundings (“a system’s entropy always increases”), can be expressed in many different forms. Kaila and Annila focus on two of these forms. When written as a differential equation of motion, the second law can describe evolution as an energy transfer process: natural selection tends to favor the random mutations that lead to faster entropy increases in an ecosystem. When written in integral form, the second law describes the principle of least action: motion, in general, takes the path of least energy.

Then, the scientists showed how natural selection and the principle of least action can be connected by expressing natural selection in terms of chemical thermodynamics. As the scientists explain, nature explores many possible paths to level differences in energy densities, with one kind of energy transfer mechanism being different species within the larger system of the Earth.

So there!


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