One of the oldest canards in the creationists’ book is the claim that evolution must be false because it violates the second law of thermodynamics, or the principle that, as they put it, everything must go from order to disorder. One of the more persistent perpetrators of this kind of sloppy thinking is Henry Morris, and few creationists today seem able to get beyond this error.

Remember this tendency from order to disorder applies to all real processes. Real processes include, of course, biological and geological processes, as well as chemical and physical processes. The interesting question is: “How does a real biological process, which goes from order to disorder, result in evolution. which goes from disorder to order?” Perhaps the evolutionist can ultimately find an answer to this question, but he at least should not ignore it, as most evolutionists do.

Especially is such a question vital, when we are thinking of evolution as a growth process on the grand scale from atom to Adam and from particle to people. This represents in absolutely gigantic increase in order and complexity, and is clearly out of place altogether in the context of the Second Law.

As most biologists get a fair amount of training in chemistry, I’m afraid he’s wrong on one bit of slander there: we do not ignore entropy, and are in fact better informed on it than most creationists, as is clearly shown by their continued use of this bad argument. I usually rebut this claim about the second law in a qualitative way, and by example — it’s obvious that the second law does not state that nothing can ever increase in order, but only that an decrease in one part must be accompanied by a greater increase in entropy in another. Two gametes, for instance, can fuse and begin a complicated process in development that represents a long-term local decrease in entropy, but at the same time that embryo is pumping heat out into its environment and increasing the entropy of the surrounding bit of the world.

It’s a very bad argument they are making, but let’s consider just the last sentence of the quote above.

This represents in absolutely gigantic increase in order and complexity, and is clearly out of place altogether in the context of the Second Law.

A “gigantic increase in order and complexity” … how interesting. How much of an increase? Can we get some numbers for that?

Daniel Styer has published an eminently useful article on “Entropy and Evolution” that does exactly that — he makes some quantitative estimates of how much entropy might be decreased by the process of evolution. I knew we kept physicists around for something; they are so useful for filling in the tricky details.

The article nicely summarizes the general problems with the creationist claim. They confuse the metaphor of ‘disorder’ for the actual phenomenon of entropy; they seem to have an absolutist notion that the second law prohibits all decreases in entropy; and they generally lack any quantitative notion of how entropy actually works. The cool part of this particular article, though, is that he makes an estimate of exactly how much entropy is decreased by the process of evolution.

First he estimates, very generously, how much entropy is decreased per individual. If we assume each individual is 1000 times “more improbable” than its ancestor one century ago, that is, that we are specified a thousand times more precisely than our great-grandparents (obviously a ludicrously high over-estimate, but he’s trying to give every advantage to the creationists here), then we can describe the reduction in the number of microstates in the modern organism as:

Now I’m strolling into dangerous ground for us poor biologists, since this is a mathematical argument, but really, this is simple enough for me to understand. We know the statistical definition of entropy:

In the formula above, k_B is the Boltzmann constant. We can just plug in our estimated (grossly overestimated!) value for Ω, have fun with a little algebra, and presto, a measure of the change in entropy per individual per century emerges.

Centuries are awkward units, so Styer converts that to something more conventional: the entropy change per second is -3.02 x 10^-30 J/K. There are, of course, a lot of individual organisms on the planet, so that number needs to be multiplied by the total number of evolving organism, which, again, we charitably overestimate at 10³², most of which are prokaryotes, of course. The final result is a number that tells us the total change in entropy of the planet caused by evolution each second:

-302 J/K

What does that number mean? We need a context. Styer also estimates the Earth’s total entropy throughput per second, that is, the total flux involved from absorption of the sun’s energy and re-radiation of heat out into space. It’s a slightly bigger number:

420 x 10¹² J/K

To spell it out, there’s about a trillion times more entropy flux available than is required for evolution. The degree by which earth’s entropy is reduced by the action of evolutionary processes is miniscule relative to the amount that the entropy of the cosmic microwave background is increased.

This is very cool and very clear. I’m folding up my copy of Styer’s paper and tucking it into my copy of The Counter-Creationism Handbook, where it will come in handy.

Styer DF (2008) Entropy and evolution. Am J Phys 76(11):1031-1033.

My latest Seed column slipped quietly onto the interwebs last week — it’s an overview of how the glues that hold multicellular organisms together first evolved in single celled creatures, represented today by the choanoflagellates.

Just as a teaser, the next print edition that should be coming out soon will continue the focus on enlightening organisms of remarkable simplicity with a description of the results of the Trichoplax genome. Get it! You will also be rewarded with a great issue focusing on science policy.

We all know the story of the Miller-Urey experiment. In 1953, a young graduate student named Stanley Miller ran an off-the-wall experiment: he ran water, methane, ammonia, and hydrogen in a sealed flask with a pair of electrodes to produce a spark, and from those simple building blocks discovered that more complex compounds, such as amino acids, were spontaneously produced. Stanley Miller died in 2007, and in going through his effects, the original apparatus was discovered, and in addition, several small sealed vials containing the sludge produced in the original experiment were also found.

This isn’t too surprising. I’ve gone through a few old scientists’ labs, and you’d be surprised at all the antiquities they preserved, all with notes documenting exactly what they are. It’s habit to keep this stuff.

Now the cool part, though: the scientists who unearthed the old samples ran them through modern analysis techniques, which are a bit more sensitive than the tools they had in the 1950s. In 1953, Miller reported the recovery of five amino acids from his experiment. The reanalysis found twenty two amino acids and five amines in the vials. He was more successful than he knew!

Moles (relative to glycine = 1) of the various amino acids
detected in the volcanic apparatus vials. Amino acids underlined have not been previously
reported in spark discharge experiments. Values for amines are minimum values because of loss due to their volatility during workup.

Yes, I know that Miller’s reducing atmosphere is no longer considered to be an accurate representation of the ancient earth’s atmosphere. However, the experiment still supported a key idea: that the synthesis of these organic compounds did not require any kind of guiding hand, but would naturally emerge from unassisted chemical reactions. Furthermore, the authors of this paper argue that while it was not a good model of the global atmosphere, it might still model local conditions in isolated areas.

Geoscientists today doubt that the primitive atmosphere had the highly reducing composition Miller used. However, the volcanic apparatus experiment suggests that, even if the overall atmosphere was not reducing, localized prebiotic synthesis could have been effective. Reduced gases and lightning associated with volcanic eruptions in hot spots or island arc-type systems could have been prevalent on the early Earth before extensive continents formed. In these volcanic plumes, HCN, aldehydes, and ketones may have been produced, which, after washing out of the atmosphere, could have become involved in the synthesis of organic molecules. Amino acids formed in volcanic island systems could have accumulated in tidal areas, where they could be polymerized by carbonyl sulfide, a simple volcanic gas that has been shown to form peptides under mild conditions.

So good work, Dr Miller!

Johnson AP, Cleaves HJ, Dworkin JP, Glavin DP, Lazcano A, Bada JL (2008) The Miller Volcanic Spark Discharge Experiment. Science 322(5900):404.