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Tuesday, August 12, 2008 | Reason : In the News | print version Print | Comments

Document Evolution as Described by the Second Law of Thermodynamics

by PhysoOrg

Thanks to SPS for the link.

http://www.physorg.com/news137679868.html

Evolution as Described by the Second Law of Thermodynamics


By viewing evolution as the motion of energy flows toward a stationary state (entropy), evolution can be explained by the second law of thermodynamics, a law which conventionally describes physical systems. In this view, a cheetah serves as an energy transfer mechanism, and beneficial mutations allow the animal to transfer more energy within its environment, helping even out the energy. Image credit: Rob Qld.

(PhysOrg.com) -- Often, physics and biology appear as different worlds, from a scientist's point of view. Each discipline has its own language and concepts, and physicists and biologists tend to look at the world in different ways — not least being from inanimate and animate perspectives.

But at the core of these two sciences is the concept of motion. As a biological ecosystem evolves by the process of natural selection, it disperses energy, increases entropy, and moves toward a stationary state with respect to its surroundings. Similarly, as energy flows in various physical phenomena, they too cause biological systems to move toward stationary states with respect to their surroundings, in accordance with the second law of thermodynamics. Whether an object is animate or inanimate, science does not seem to make a distinction. In both cases, energy flows toward a stationary state, or a state of equilibrium, in the absence of a high-energy external source.

In this way, explain Ville Kaila and Arto Annila of the University of Helsinki, the second law of thermodynamics can be written as an equation of motion to describe evolution, and, in doing so, connect biology with physics. Their study, "Natural selection for least action," is published in the Proceedings of The Royal Society A.

The second law of thermodynamics, which states that the energy of a system tends to even itself out with its surroundings ("a system's entropy always increases"), can be expressed in many different forms. Kaila and Annila focus on two of these forms. When written as a differential equation of motion, the second law can describe evolution as an energy transfer process: natural selection tends to favor the random mutations that lead to faster entropy increases in an ecosystem. When written in integral form, the second law describes the principle of least action: motion, in general, takes the path of least energy.

Then, the scientists showed how natural selection and the principle of least action can be connected by expressing natural selection in terms of chemical thermodynamics. As the scientists explain, nature explores many possible paths to level differences in energy densities, with one kind of energy transfer mechanism being different species within the larger system of the Earth.

Mechanisms of energy transduction, especially biological species, can be intricate and complex. By randomly mutating individuals of a species, various paths are explored in the quest of increasing entropy most rapidly. These mutations sooner or later naturally converge on the most probable path. Although the energy landscape keeps changing, the most probable path is always that which is the shortest and follows the steepest energy descents. It leads toward a stationary state, such as an ecosystem evolving toward a state that will have just the right amount of plants, plant eaters, and other energy transfer mechanisms (both living and non-living) to maintain the highest rate of energy dispersal.

"In a biological context, when two rather similar species (i.e. energy transduction mechanisms) compete for the same source of energy (e.g. food), the one with even slightly more effective mechanisms (e.g. claws, teeth, feet, etc.) captures more than the other," Annila explained to PhysOrg.com. "Gradually, the population of the more effective species will increase at the expense of the other. The overall process is pictured as flows of energy that gradually and naturally select the more effective, steeper paths. In biology, this physical consequence, which can be deduced from Lyapunov stability criterion, is known as the competitive exclusion principle.

"Let us assume that a mutation happens to improve the speed of a cheetah," he added as an example. "Consequently, this cheetah will catch more food, i.e. more energy will channel through this individual — the path has become steeper. Likewise, a deleterious mutation will reduce the flow via the particular path that has turned less steep. In this case, the non-mutated paths are the healthy rivalries, and will enjoy correspondingly larger flows due to the diminished competition."

The researchers note that this abstract description provides a holistic view of evolving nature, not a detailed explanation for how individual species emerge from the process. For example, plant-eating species distribute the solar energy acquired by photosynthesis, and the cheetah, as a carnivore, disperses energy further down along the gradients of the food chain, which eventually terminates into cold space. And since these energy flows themselves yield and affect energy transfer mechanisms that, in turn, alter the flows, it's virtually impossible to predict evolution's next move.

"A system evolves to reach a stationary state with respect to its surroundings," Annila explained. "That is to say, when the surrounding environment is high in energy, then the system will evolve to a high-energy stationary state. Matter on Earth has evolved over eons in increasing its energy content to match that of the solar radiation density. During this process, mechanisms of energy transduction have improved, but presumably there are still ways to catch more of the sunlight to power activities that are presently fueled by non-renewables."

The idea of using the second law of thermodynamics to describe evolution is not new. As far back as 1899, physicist Ludwig Boltzmann, a great admirer of Darwin, was contemplating about connection. Also, Alfred J. Lotka, in his main work published in 1925, expressed full confidence that biotic systems follow the same universal imperative. Many scientists today have recognized the principle of increasing entropy as a way to understand life. The connection between increasing entropy and decreasing free energy, provided by Kaila and Annila via the principle of least action, has further strengthened the unified description of natural motions.

More information: Kaila, Ville R. I. and Annila, Arto. "Natural selection for least action." Proceedings of The Royal Society A. doi:10.1098/rspa.2008.0178.

Comments 1 - 50 of 60 |

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1. Comment #228738 by astroprof on August 12, 2008 at 1:23 pm

 avatarThis article should be required reading for people who claim that evolution violates the Second Law of Thermodynamics. Funny how people who make this claim have never taken a class on thermo. or biology for that matter.

Other Comments by astroprof

2. Comment #228754 by Steve Zara on August 12, 2008 at 1:50 pm

 avatarComment #228752 by Simonw

If you want to prove evolution doesn't violate the second law of thermodynamics one can show order created by the energy of the sun by looking at any plant growing. It is a lot easier than reading this article, and a lot more "obvious".


I think this is saying a bit more than just "evolution doesn't violate the second law", but that given the laws of thermodynamics, combined with a supply of order (such the directional energy of the sun), then evolution of life is inevitable.

Other Comments by Steve Zara

3. Comment #228767 by the great teapot on August 12, 2008 at 2:08 pm

Evolution can be explained by the second law of thermodynamics.
Thank god for that, where would the theory of evolution be without the second law of thermodynamics, screw the fossil records here is the second law of thermodynamics coming to our rescue.
Anyway, I ve read the title, now for the rest of the article.

Other Comments by the great teapot

4. Comment #228779 by Steve Zara on August 12, 2008 at 2:19 pm

 avatarComment #228772 by Bruno

Did anybody else understand it that way?


Not me. I read that evolution operates because of thermodynamics. It isn't just similar, it is a consequence. This is clear from the following sentence:

Then, the scientists showed how natural selection and the principle of least action can be connected by expressing natural selection in terms of chemical thermodynamics.

Other Comments by Steve Zara

5. Comment #228781 by TuftedPuffin on August 12, 2008 at 2:25 pm

 avatarI'm going to coin a term here...this is an example of "greedy holism". Instead of reducing something to its components, these people seem to be saying that a large, complex system obeys a general rule, without bothering to show how this relates to the behavior of its parts.

Evolution operates like...evolution. Evolution is what happens when a bunch of genes compete. Attaching some grand "evening out energy" purpose to it seems vacuous at best and misleading at worst. Maybe I simply don't get the central point of this, but it doesn't look like anything real is being said here.

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6. Comment #228794 by Steve Zara on August 12, 2008 at 2:39 pm

 avatarComment #228781 by TuftedPuffin

Attaching some grand "evening out energy" purpose to it seems vacuous at best and misleading at worst.


It isn't any kind of purpose. It is basic thermodynamics. Life can arise and maintain its structure and complexity because it "feeds off" order provided primarily by the sun.

To put things simply, the Sun provides a source of order because it is highly directed energy within relatively narrow wavelengths. Life can use that order to keep itself going because it increases overall entropy by radiating off energy in a far less ordered state (this is the energy transference that is mentioned).

I think this is a very useful way of looking at things. I think it is a misunderstanding to consider this superfluous to fossil studies etc. Fossils show what happens when evolution is driven by thermodynamics, at least in a sense.

This helps to show that natural selection is a more fundamental part of nature than many might have thought.

Other Comments by Steve Zara

7. Comment #228807 by phil rimmer on August 12, 2008 at 2:52 pm

 avatarAn article on this idea (evolution driven by thermodynamics) many years ago in the New Scientist gave the contracted hand waving explanation that systems always sought the most effective (speedy) path for increasing entropy. As a general rule more complex arrangements can make for more effective heat transfer than simple arrangements. Hence, systems would become more complex, speeding heat transfer until some limit or other made any further increase in complexity counter-productive.

To illustrate this point it was imagined that a pan of water would be heated uniformly from underneath. The water convection would migrate from some simple initial pattern to a more complex one of multiple hexagonal cells that maximised the rate of flow of water and hence of heat. (The minimum/optimum cell size, is in fact limited by the water depth. Optimal circulation happens with uniform circulation velocities and hence circular paths. Cell size, therefore, approximates water depth.)

Other Comments by phil rimmer

8. Comment #228811 by agn on August 12, 2008 at 2:58 pm

The crucial point here is the connection with the principle of least action.
This is just about the most overarching principle of systemo-dynamic thinking in all of physics (not at all constrained merely to thermodynamics), and I am thrilled that the principle of evolution may be our old friend, the least action principle, in yet another disguise.

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9. Comment #228814 by Steve Zara on August 12, 2008 at 3:03 pm

 avatar
I am thrilled that the principle of evolution may be our old friend, the least action principle, in yet another disguise.


Absolutely. It means that evolution isn't really that special, and it isn't improbable. It is likely to be a fundamental part of nature.

Other Comments by Steve Zara

10. Comment #228815 by Brian English on August 12, 2008 at 3:04 pm

 avatarSteve, you've disappeared. The exercise program was too successful?

Other Comments by Brian English

11. Comment #228816 by decius on August 12, 2008 at 3:06 pm

 avatar. Comment #228815 by Brian English

His husband mistakenly sprayed him with fertilizer and the foliage took over.

Other Comments by decius

12. Comment #228818 by Brian English on August 12, 2008 at 3:09 pm

 avatarAre you suggesting that the plants are growing out of his shirt and obscuring his visage?

Other Comments by Brian English

13. Comment #228820 by Quetzalcoatl on August 12, 2008 at 3:11 pm

 avatarBrian-

Are you suggesting that the plants are growing out of his shirt and obscuring his visage?


Or he stood there too long and the plants grew through his head.

And on that cheery note, I'm off to bed.

Other Comments by Quetzalcoatl

14. Comment #228821 by decius on August 12, 2008 at 3:11 pm

 avatarComment #228818 by Brian English

Precisely.

Other Comments by decius

15. Comment #228824 by Brian English on August 12, 2008 at 3:13 pm

 avatarNight Quetz. Don't let the christians bite. :)

Other Comments by Brian English

16. Comment #228825 by phil rimmer on August 12, 2008 at 3:14 pm

 avatarComment #228816 by decius
the foliage took over.


His face got more complex to help dissipate all those unwanted calories.

*coat*

Other Comments by phil rimmer

17. Comment #228829 by Angels On a Pin Head on August 12, 2008 at 3:20 pm

The author of this article, Lisa Zyga, also wrote the article that appeared a while back on the perpetual motion machine.

Judging by that, I wouldn't trust her on the subject of thermodynamics. Not to say that she must be wrong here, but I'd reserve judgement until you read the paper yourself or until a more reliable source reports on it.

Other Comments by Angels On a Pin Head

18. Comment #228830 by decius on August 12, 2008 at 3:20 pm

 avatarComment #228825 by phil rimmer

He now is a sort of Marvel superhero.



the Ivy Man

Other Comments by decius

19. Comment #228831 by the great teapot on August 12, 2008 at 3:20 pm

Agn
I do not understand your reply.I do not want your pity nor your sarcasm,an explanation would be more helpfull. If you have one.

Other Comments by the great teapot

20. Comment #228832 by phil rimmer on August 12, 2008 at 3:22 pm

 avatarDecius

I'm on the phone to Stan Lee right now. I think you're on to something.

:clap:

Other Comments by phil rimmer

21. Comment #228833 by Brian English on August 12, 2008 at 3:23 pm

 avatarOK, the universe is increasing in entropy. One of the processes by which entropy is increased is life. If it weren't for the sun, we'd be up to our eyeballs in entropy.

EDIT: I haven't read the article, so I probably just contradicted it. :D

Other Comments by Brian English

22. Comment #228836 by phil rimmer on August 12, 2008 at 3:31 pm

 avatarComment #228833 by Brian English
OK, the universe is increasing in entropy. One of the processes by which entropy is increased is life. If it weren't for the sun, we'd be up to our eyeballs in entropy.


The interesting point to the New Scientist illustration I quoted is that there is an upper (optimum) limit on complexity in any given circumstance.

So, are we optimally complex now?

Other Comments by phil rimmer

23. Comment #228837 by Brian English on August 12, 2008 at 3:33 pm

 avatar
Hence, are we optimally complex now?
Nope, I've been altering my behavior to not sweat the difficult issues and I just chill these days. See! I've outsmarted thermodynamics....

Other Comments by Brian English

24. Comment #228843 by Steve Zara on August 12, 2008 at 3:37 pm

 avatarComment #228819 by the great teapot

physics has no detailed explanation for the specifics of evolution. Any credit here is surely unwarranted.


This isn't about specifics. It is about driving forces. Much of nature is chaotic, but we still look for general explanations even though we can't predict the behaviour of every particle.

I think you are missing the point. This isn't saying that thermodynamics explains everything about evolution, but that evolution seems to be a natural consequence of thermodynamics.

It is a bit like, for example, the formation of our solar system. It was chaotic, and you could not have started out with a gas cloud and predicted the formation of the Earth, but you can understand that gravity was a driving force.

Other Comments by Steve Zara

25. Comment #228844 by phil rimmer on August 12, 2008 at 3:38 pm

 avatarBrian
See! I've outsmarted thermodynamics....


Clever. No, cool!

Other Comments by phil rimmer

26. Comment #228845 by Brian English on August 12, 2008 at 3:39 pm

 avatarSteve, if you can't explain the complete history of every particle that's ever been then your explanation is incomplete and god did it. :)

Other Comments by Brian English

27. Comment #228846 by the great teapot on August 12, 2008 at 3:40 pm

Are we optimally complex now?
Wtf are you stupid phil did you not read what the
mathematical&theoretical unification had to say about that. fool.

Other Comments by the great teapot

28. Comment #228849 by the great teapot on August 12, 2008 at 3:44 pm

steve.
As ever ,many thanks for your patience in trying to explain. to an idiot.
Brian,
Iam not looking for the answer to life, the universe and everything, (well I am) but religion has taught me to be wary of anything that makes claims beyond it's capabilities. I do not exclude anything from this constraint.

Other Comments by the great teapot

29. Comment #228850 by phil rimmer on August 12, 2008 at 3:47 pm

 avatarComment #228846 by the great teapot:
are you stupid phil


Guess I must be, hence, I am insufficiently complex, hence, I am not pulling my "entropic weight".

My act of folly has deferred the heat death of the universe. (You may thank me later.)

Other Comments by phil rimmer

30. Comment #228853 by Brian English on August 12, 2008 at 3:50 pm

 avatarPhil, give me that heat! Don't you know it's winter here? I want to dissipate more energy and increase the entropy around my toes.

Other Comments by Brian English

31. Comment #228855 by phil rimmer on August 12, 2008 at 3:57 pm

 avatarComment #228853 by Brian English:
Phil, give me that heat! Don't you know it's winter here?


Sorry, can't help you, mate. It appears to be winter here too. Torrential rain, overcast, typical British summer, in fact.

EDIT curses, lots of posts have gone invisible again....

Other Comments by phil rimmer

32. Comment #228858 by Brian English on August 12, 2008 at 4:03 pm

 avatarApologies Phil. It's probably colder where you are. :)

Other Comments by Brian English

33. Comment #228860 by fizhburn on August 12, 2008 at 4:07 pm

 avatar
curses, lots of posts have gone invisible again....
The site is disintegrating as entropy increases, run!

Other Comments by fizhburn

34. Comment #228861 by 35bluejacket on August 12, 2008 at 4:08 pm

Well….there it is; the answer to the religious question of"What is the purpose of life or creation?" It is: To come to a balance or stability. How elegant.

Other Comments by 35bluejacket

35. Comment #228863 by phil rimmer on August 12, 2008 at 4:11 pm

 avatarFizh!

The site is disintegrating as entropy increases, run!


Whilst we're running, I've just realized you've nicked my shades.

Other Comments by phil rimmer

36. Comment #228864 by agn on August 12, 2008 at 4:11 pm

Nope, bluejacket:
We're just perturbations. I liked perturbation theory very much

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37. Comment #228866 by Brian English on August 12, 2008 at 4:14 pm

 avatarFizhburn, stop stealing my order. My world is disordered enough.

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38. Comment #228868 by fizhburn on August 12, 2008 at 4:28 pm

 avatar*cheeses it with style, amazon.com box*





Edit: I'm with Steve Zara, this result tying energy dissipation gradients to structural complexity in biology is extra cool. (Said fizhburn, having forgot everything he ever learnt about system dynamics.)

Edit edit: original article here.

Edit edit edit: Life as a manifestation of the second law of thermodynamics.

Other Comments by fizhburn

39. Comment #228869 by tuskensp on August 12, 2008 at 4:38 pm

 avatarThe fact there is calculus involved in the aforementioned article will automatically make it incomprehensible to the large majority of creationists. I know it has been debated as to whether IQ or education affects a person's religiosity, but to me there is no doubt.

Other Comments by tuskensp

40. Comment #228873 by agn on August 12, 2008 at 4:42 pm

Hmm..religiosity definitely dumbs a person down, but I don't think being dumb makes you attracted to religiosity as such

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41. Comment #228874 by Szymanowski on August 12, 2008 at 4:44 pm

 avatar
to describe evolution, and, in doing so, connect biology with physics
Eh? Biology was unconnected with physics before this paper?

/pedant

Other Comments by Szymanowski

42. Comment #228875 by Brian English on August 12, 2008 at 4:48 pm

 avatarYes, biology was located in Building 12A and Physics down the road at the other campus.

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43. Comment #228882 by phil rimmer on August 12, 2008 at 5:05 pm

 avatarRemember this is not just about optimized biological complexity, it is about all complexity as part of the original paper's conclusion makes clear (thanks fizhburn)-

Particularly, intriguing phenomena may emerge when a high-energy source, such as the Sun, is powering a large energy transduction network, such as that on Earth. When a steady stream of external energy is falling on an open system, there is a driving force to assemble mechanisms from the available ingredients and to improve on them in order to acquire more energy in the quest for a stationary state. The driving force makes no difference between abiotic and biotic mechanisms of energy transduction but favours all those that are dispersing energy more and more effectively. Therefore, the large global system is, in the language of thermodynamics, an energy manifold in myriad motional modes, most of which are referred to as life. For the large global system that apparently has a suitable mixture of ingredients to couple to the high-energy influx, it has taken aeons to evolve in energy transduction. Although the abstract description of evolution provided by the statistical physics results in a holistic view of nature, it is unarmed to say specifically how energy transduction mechanisms, i.e. species, have emerged. These questions can be addressed by appropriate models. The present formalism emphasizes the imperatives in evolution.


Note the agnosticism of the process towards abiotic and biotic. I wonder how far you can push this? Do major life extinction events always correspond to increased processes of abiotic transduction? Isn't this just a fancy term for a cataclysm?

Other Comments by phil rimmer

44. Comment #228886 by Bonzai on August 12, 2008 at 5:19 pm

I agree with steve, this is a very cool idea.

The great teapot

physics has no detailed explanation for the specifics of evolution. Any credit here is surely unwarranted.


On the contrary, physics seeks underlying, structural laws, there is a sense of logical necessity to laws of physics which is not apparent in biology. It would be nice if evolution can be shown to have a deep, physical explanation instead of viewing organisms as only "historical accidents" resulting from the haphazard working of natural selection.

Other Comments by Bonzai

45. Comment #228897 by Styrer- on August 12, 2008 at 6:10 pm

Whether an object is animate or inanimate, science does not seem to make a distinction. In both cases, energy flows toward a stationary state, or a state of equilibrium, in the absence of a high-energy external source.


Ignorant as I am, I wonder if this idea, which evidently has at least some pedigree, could possibly throw some light on abiogenesis? If the above quote is true, then could 'energy transduction mechanisms' include non-biological entities?

Should I get me coat?

Best,
Styrer

Other Comments by Styrer-

46. Comment #228916 by prettygoodformonkeys on August 12, 2008 at 8:05 pm

 avatarjosh:

.commentText -->


WTF?

Other Comments by prettygoodformonkeys

47. Comment #228924 by spiderdancer on August 12, 2008 at 8:49 pm

Hmmm. I'm a bit sceptical that this is saying anything more than "evolution is consistent with the 2nd law".

We already knew this but maybe it's adding a bit more meat to the bones of that argument. I don't think it allows us to predict anything, for instance it is silent on the question of all organisms evolved from a common ancestor.

Other Comments by spiderdancer

48. Comment #228995 by GBile on August 13, 2008 at 1:56 am

 avatarI am also experiencing an acute outbreak of the feared

'.commentText -->' disease.

The 'Other comments by ...' seems to be the culprit.

Can this be cured ?

Other Comments by GBile

49. Comment #228996 by atp on August 13, 2008 at 2:02 am

Wow! The whole article reads just like it was some fancy new age stuff that wanted to look like science.

But it makes enough sense to me to look like a viable way of looking at evolution in the context of energy.

I am not a physics expert, and have always had a problem with one aspect of entropy. It is said that in a _closed_ (was missing in the article) system entropy tends to increase continuously. So that there is no problem with subsystems where entropy decreases, i.e. self organization in an open subsystem does not violate the second law of thermodynamics.

But what I've never really grasped is how energy input into (or flow through) an open system, when that results in locally decreased entropy, is causing overall increased entropy?

Anyway, an interesting article I will be sure to reread a couple of time.

Other Comments by atp

50. Comment #228999 by Steve Zara on August 13, 2008 at 2:10 am

 avatarStyrer-

Ignorant as I am, I wonder if this idea, which evidently has at least some pedigree, could possibly throw some light on abiogenesis? If the above quote is true, then could 'energy transduction mechanisms' include non-biological entities?


I hope it starts to blur the boundaries between evolution and abiogenesis. We will see a continuum between complex chemistry and physics and replicators containing information-encoding molecules (such as RNA and DNA). There may even be some kind of principle that information-encoding structures inevitably arise because they lead to such efficient transduction of energy.

Other Comments by Steve Zara
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