Impossible evolutionary steps?

"Your definitions are all wrong. You don't know what is meant by a closed system. When you find out, tell me what is the difference between a closed system and an isolated system."

It depends on whose defintions you want to use.

Some use "isolated" and "closed" interchangeably. In this case, these are systems in which neither energy nor matter cross the boundary.

Some then differentiate between the two. "Isolated" comes to mean a system in which neither energy nor mass is transferred in or out while "closed" means that only energy is transferred across the boundary.

I see where you are going with this. However, if you choose to use the second set of definitions then you are still missing the boat because the total entropy of a system is only required to increase if it is an isolated system.

In the second set of definitions, where a closed system allows for energy transfer but not mass transfer across the boundary, the entropy of the closed system can still decrease because it is capable of passing energy across the boundary.

If you chose the second set you must then say that entropy can only increase in an isolated system. For in a closed system, where energy can pass the boundary, entropy can decrease.

And I think we could have a discussion over how much mass transfer across the boundary is required for it to even be closed. Since the earth does exchange some mass with space, it is in the strictest sense an open system. If you take the first definition for closed and isolated, then the earth is still an open system solely because of the exchange of energy.

By differentiating between closed and isolated you can at least try and make a cse that the system is closed by the entropy requirement then only holds for an isolated system.

 

Best to define your terms up front, otherwise nobody knows what you mean.

Mike

 

We can bog down on definitions, but whatever definitions you choose, entropy is only required to increase for systems that exchange neither mass nor energy across their boundary. So the earth is not limited to only increasing entropy. Of course, even if it were, this would not apply to smaller systems within the boundary of the earth. Every living system is exchanging both matter and energy with the enviroment so there is no requirement for the entropy of these systems to be only increasing. Furthermore, these systems do not operate at equilibrium conditions which throws another complication into the whole discussion.

But the short of it is that the earth exchanges energy with the universe so there is no requirment that its entropy only increase.

And nothing about entropy has yet been shown to prevent any of the mechanisms of evolution.

 

It is an example because it is a case where the entropy of a system spontaneously decreaes. You are correct about why it happens, but that is beside the point. If you are going to dismiss it because you understand the underlying reason for the decrease, then you will do the same for all other examples. Except, perhaps, for example that are revelant to life processes.

 

Wrong. I have shown that you can't have photosynthesis without plants.

Now, if you have a very large budget, and you can pay me a lot of money, I could go through every chemical process that is alleged to have occured at every stage of evolution. It would be a mammoth task, because there are an immense number of processes occurring just in one species. But I could add up the Gibbs free energies of all the reactants and products and see if they come out feasible. This would produce many volumes of documentation but I would be prepared to do it (and set up a reasearch unit with a large staff) if you have got the money.

However, I've made it simple by giving you the example of photosynthesis. This is the only way up Thermodynamic Hill, and all the other processes are just sliding down again.

Mike

 

Surely you jest. Water freezes spontaneously!!!!! I suppose water boils spontaneously also!!!!!!

Again I assume you jest. Who has stated that the earth is a closed system? I repeat an earlier quote for your edification:

Harvard scientist John Ross, in a letter to Chemical and Engineering News [July 7, 1980], writes: "There are no known violations of the Second Law of Thermodynamics. Ordinarily the Second Law is stated for isolated systems, but the Second Law applies equally well to open systems. . . There is somehow associated with the field of far from equilibrium phenomena the notion that the Second Law of Thermodynamics fails for such systems. It is important to make sure that this error does not perpetuate itself."

 

"Wrong. I have shown that you can't have photosynthesis without plants."

First, I was unaware that photosynthesis was a mechanism for evolution.

Second, I doubt that photosynthesis was the first reaction (well, actually using the sugar produced from photosynthesis) that provided energy to living organisms. This would have likely been a chemical reation with components of the enviroment of the first life.

So, no, you have yet to demonstrate that entropy prevents any of evolutions mechanisms.

 

"Surely you jest. Water freezes spontaneously!!!!! I suppose water boils spontaneously also!!!!!! "

The boiling of water increases its entropy. It requires an input of energy to happen. Water does evaporate without boiling however this is still an increase in entropy.

Last night my dog's water dish froze. I did nothing. The water in that dish just decreased in entropy through purely natural processes.

"Harvard scientist John Ross, in a letter to Chemical and Engineering ..."

Who said that the second law does not apply for an open system? You misunderstand. However, the key point is that there is no requirement for the entropy of an open system to increase.

Only a system which is not exchanging mass or energy is required to only increase in entropy.

 

"Spontaneous" means [Websters New Universal Unabridged Dictionary]
1. coming or resulting from natural impulse or tendancy.
2. independent of external agencies, self acting.

Do you use air conditioning in Alabama or are your homes spontaneously cooled? Wish that happened in South Carolina, in fact think of all the energy we could save if it happened in other states.

 

First, spontatneous has a very specific definition in thermosynamics which must be separated from any lay definiton.

Second, that water froze all on its own. No air conditioning at all. Its going to be about 16 tonight. Brrr.

Finally, in the case of AC, you are taking heat and forcing it to be trnasferred from the cooler area, the inside, to the warmer area, the outside. This is not favorable and requires work to accomplish.

 

The water did not freeze all on its own. That statement is foolish. It froze because its temperature dropped below 32 degrees F through heat transfer to its surroundings, a thermodynamic event. It is not a spontaneous event! Get real!!!

 

Just a couple of points from someone who has had several courses in thermodynamics. Ice certainly has less entropy than a similar mass of liquid water. Natural processes routinely involve materials going to a state of lower entropy. The formation of ice from water is one such example.

Evolution is not prohibited by the 2nd law. Those who say that the second law is a problem for evolution do not understand thermodynamics.

 

Just a couple of points from someone who has had several courses in thermodynamics. Ice certainly has less entropy than a similar mass of liquid water. Natural processes routinely involve materials going to a state of lower entropy. The formation of ice from water is one such example.

Evolution is not prohibited by the 2nd law. Those who say that the second law is a problem for evolution do not understand thermodynamics.