Actually, it is entirely sensible to think that the original emergence of life and complex pre-biotic chemistry was actually driven by the needs of thermodynamics. This sounds counter intuitive at first, but the key is precisely what ZikZak has said. The energy from the sun is very low entropy energy.
Since it is a blackbody spectrum, and the entropy is simply 1/5780 per unit energy -- the inverse of temperature of the blackbody emitter. (Entropy has units J/K). The Earth then radiates this out into the cold of space, as radiation which with a spectrum of around 255K. Radiation into space goes mostly from high up in the atmosphere at a temperature of around -18C.
It is normal, in all kinds of physical systems, for local dynamic structures to emerge that help to dissipate energy. As a simple example, the Earth has a water cycle, with water endlessly cycled up from the oceans and raining back down again, and flowing down rivers to the sea. This cycle is driven by the energy flow from the Sun. It works to help dissipate energy more effectively! That is, the evaporation and precipitation of water transports large amounts of energy from the warm surface up to the cooler reaches of the upper atmosphere. It's called "latent heat". Evaporation at the surface has a cooling effect, as energy goes into the liquid gas transition. In the atmosphere, condensation releases this energy back again. All told, this process is responsible to transporting, on average, more than 70 W/m^2 over the whole Earth's surface. That's a lot of energy! And it helps transport heat more efficiently up from the surface and into space, which is helping to move energy from warm regions to cold ones, which is the whole basis of the second law.
Now the water cycle is a kind of local organization of matter. It is a structure, arising spontaneously in the presence of a large continuous flow of energy. There are many many other such examples, wherever there is a big energy flow from hot to cold. Structure tends to emerge in such a way that the energy flows faster, and so that entropy increases more rapidly.
The spontaneous emergence of a water cycle may look like a spontaneous emergence of order; but in fact it is contributing to the increase in entropy by speeding up the rate at which energy is dissipated.
Life is very good at dissipating energy as well. Living things, by their metabolism, are consuming energy, and emitting an equal amount of waste energy... but with higher entropy. The day to day operation of living things is helping to increase entropy faster than would occur if life was not around. Sure, the emergence of structure invariably involves some local decrease in entropy. This is overwhelmed, by many orders of magnitude, by the metabolism of life in operation to consume high grade energy sources and expel it as high entropy waste. It is
expected for local structures to emerge that help consume energy in this way.
Precisely how life emerged is, of course, still a mystery in many of its details. But thermodynamically speaking it is probably something that should be expected.
This was best expressed by http://en.wikipedia.org/wiki/Ilya_Prigogine" , who pioneered developments in the thermodynamics of systems that are far from equilibrium, and the theory of "dissipative structures". He won the 1977 Nobel prize in chemistry for this work.
Only months before he died, he was good enough to address this very issue, at my own request, for the benefit of the talkorigins website and our feedback column. This website deals with all kinds of popular confusions in relation to life and evolution. You can read the feedback response I wrote about Prigogine's work at
talkorigins feedback for Jan 2003. My own real name is "Chris Ho-Stuart", and I used it in that response.
Here's a brief repeat of some of that feedback. First, an extract from "
http://www.aeiveos.com/~bradbury/Authors/Evolution/Prigogine-I/ToE.html"", by Ilya Prigogine, Gregoire Nicolis and Agnes Babloyantz, in
Physics Today, Nov 1972, pp 23-28:
What is the thermodynamic meaning of prebiological evolution? Darwin's principle of "survival of the fittest" through natural selection can only apply once pre biological evolution has led to the formation of some primitive living beings. A new evolutionary principle, proposed recently by Manfred Eigen. would replace Darwin's idea in the context of prebiotic evolution. It amounts to optimizing a quantity measuring the faithfulness, or quality, of the macromolecules in reproducing themselves via template action. We here propose an alternative description of prebiological evolution. The main idea is the possibility that a prebiological system may evolve through a whole succession of transitions leading to a hierarchy of more and more complex and organized states. Such transitions can only arise in nonlinear systems that are maintained far from equilibrium; that is. beyond a certain critical threshold the steady-state regime becomes unstable and the system evolves to a new configuration. As a result, if the system is to be able to evolve through successive instabilities, a mechanism must be developed whereby each new transition favors further evolution by increasing the nonlinearity and the distance from equilibrium. One obvious mechanism is that each transition enables the system to increase the entropy production. [...]
For a very brief and non-technical statement of what Prigogine is proposing...
The second law is, roughly, that entropy increases in all processes, or that heat will flow from hot things to cold things. Roughly speaking, entropy measures the extent to which energy is dissipated in a system. Open systems in a state of great energy flux (like the Earth) will tend to remain far from equilibrium. More importantly, Prigogine shows that in these conditions, ordered structures tend to form which facilitate the net dissipation of energy. Such systems help to drive the universe as a whole to states of increasing entropy, while being maintained in ordered state themselves. The paper goes on to give examples.
Far from proposing thermodynamics as a problem for the origins of life, this paper is proposing that thermodynamics and the second law is a major contributing factor to the spontaneous formation of complex dissipative structures in prebiotic evolution.
Cheers -- Sylas
