Wednesday, August 24, 2011

Entropy and the 2nd Law

If you really want to understand Entropy better watch this entire lecture series from Yale, but especially this segment:

23. The Second Law of Thermodynamics and Carnot's Engine

But please at least learn this one thing.

Entropy is the energy in a system no longer available for doing work. This does NOT mean that localized entropy cannot decrease (e.g., this is exactly what an A/C unit does), as long as the entropy of the entire System increases.

When the localized Entropy of an RNA or DNA molecule is lowered by work done with energy released from process of ATP -> ADP hydrolysis the total Entropy increases (you can calculate this using equations for Chemical Entropy if you have a specific reaction in mind).

Sunlight is used by plants to convert water and carbon dioxide into LOWER entropy molecules (sugars, etc). This is all Very Basic Science - pre-101 and is extremely well-known, studied, and the entropy calculations have been carried out to Many decimal places in study after study after study. When your body re-energizes ADP back into the LOWER Entropy molecule ATP it is doing the exact same thing and it's no Miracle™ because again, while the entropy of ADP is lowered during the chemical change the TOTAL entropy of the system increases.

It is an absolutely absurd proposition to object to "evolution" on thermodynamic grounds - anyone doing so is either ignorant, incompetent, or just flat out lying.

More resources that look specifically at evolution and thermodynamics:

Does evolution contradict the second law of thermodynamics?

Talk Origins: Thermodynamics, Evolution and Creationism

Google Scholar Resources


  1. Is the Universe always zero-entropy?

    Physicist Proposes Solution to Arrow-of-Time Paradox

    cf. Lorenzo Maccone. “Quantum Solution to the Arrow-of-Time Dilemma.” Physical Review Letters 103, 080401 (2009)