How is evolution controversial to the second law of thermodynamics?

Answer 1

Evolution does not violate the second law of thermodynamics. Anyone who says that it does lacks a correct understanding of the second law of thermodynamics or of evolution, or of both. The controversy originates in a misunderstanding of the second law. In oversimplified form, the second law implies that all natural processes increase the disorder of the universe. The catch is that many natural processes are expected to increase order locally but decrease the order overall. The "disorder" generally comes about from the increase in temperature of the surroundings. Warmer objects have more "disorder" because their molecules are moving around more. Colder objects are less disordered because their molecules are moving around less. A more rigorous definition of the second law is that heat flows from a warmer source to a cooler "sink". Heat does not spontaneously move from something cold into something hot. All this business about increased disorder (aka entropy) is just a byproduct of that. Another way to see this is to look at the actual definition of entropy:

dS = δQ/T

where

S is entropy

Q is heat

T is absolute temperature.

Notice that entropy is all about the flow of heat, which all your experience tells you flows from hot to cold. The second law actually predicts that some natural processes will increase local order (with a release of heat to the surroundings).

AnswerThe second law of thermodynamics states that things naturally tend to become more and more disordered over time, which appears to be in conflict with the idea of evolution, where organisms become increasingly complex over time. However, there really isn't a conflict because in order to maintain its level of "order" an organism generates far more "disorder" as a result of its metabolic processes. AnswerThis law maintains that spontaneous processes in closed macroscopic systems are accompanied by an increase in entropy. A closed system is a system that does not exchange matter or energy with its surroundings. Of course, the second law also has applicability to systems that exchange energy or information with the environment, but in that case there is no requirement for the entropy of the system to increase. Living things are not closed systems, and each healthy, living organism continually and largely successfully resists an increase in its entropy. For example, during the time from conception to birth, the entropy of a child, and of the mother as a whole, decreases.

We know that varieties can arise over time in a species - this is not controversial. And varieties are associated with increased entropy in the gene pool of the species. But, suppose that one of several varieties, in a single species, becomes extinct. Perhaps that variety is not as well camouflaged as others, and falls prey more readily, thus validating natural selection. The result of the extinction of this variety will clearly be a reduction in the entropy of the species.

Moreover, the extinction of one variety, as a result of natural selection, does not in any way affect the entropy of the surviving individuals or varieties, which are genetically unaware of that extinction. So, purporting to apply the second law of thermodynamics to exclude the evolution of species is quite meaningless.

Natural selection actually works by choosing individuals or varieties least likely to pass on their genes through descendants.