Skeptics of biological evolution often claim that evolution requires a decrease in entropy, giving rise to a conflict with the second law of thermodynamics. This argument is fallacious because it neglects the large increase in entropy provided by sunlight striking the Earth. A recent article provided a quantitative assessment of the entropies involved and showed explicitly that there is no conflict. That article rests on an unjustified assumption about the amount of entropy reduction involved in evolution. I present a refinement of the argument that does not rely on this assumption.

Topics
Biomass energy sources, Laws of thermodynamics, Equilibrium thermodynamics, Entropy, Chemical bonding, Educational assessment, Evolutionary biology, Amino acid, Bacteria, Proteins
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Imagine that there are na amino acids in solution, with N available quantum states. Nondegeneracy means that N⪢na⁠. The multiplicity is Ω(na)=(Nna)⁠. Taking one molecule out of solution causes the multiplicity to decrease by a factor Ω(na)∕Ω(na−1)=(N−na+1)∕na≈N∕na=nQ∕n⁠.

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If we adopt a much narrower view of which changes are due to evolution, these estimates would not apply. Even in this case, the factor of 103 would still lack justification.

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12.

Creating all of life in 6days might be thermodynamically problematic, however.

© 2009 American Association of Physics Teachers.
2009
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