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Evolution Questions

Discussion of everything related to the Theory of Evolution.

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Evolution Questions

Postby ERS » Thu Dec 16, 2004 5:54 am

Evolution is a topic everybody hears about (good, bad and everything in between), and it is fun to think about so why not!

How would you explain the nature of the 2nd Law of Thermodynamics in relation to evolution? It states that in a closed loop system a reaction cannot increase in order or energy... The closed loop system obviously would have to include the sun as everything on this planet relies on sunlight to keep the energy flow going. The Theory of Evolution seems to contradict that law. How would you explain this?

Thanks for any input!

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Postby biostudent84 » Thu Dec 16, 2004 6:06 am

Explain how it would contradicts that law. When used in ecology the Second Law applies to trophic levels. The further up the food chain you go, the less energy and less biomass there is.
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Postby ERS » Thu Dec 16, 2004 6:37 am

In ecology, the energy transfer from one trophic level to the next is only about 10%, and as you have hinted the higher up you go the less consumable biomass—beaks, bones, etc.. Because not all energy is transferred to the next level and there is a reduction in consumables; we can say that it is not an efficient system—i.e. it loses heat, energy etc. somewhere in the mix of things. So really the 2nd law of thermodynamics holds quite well in your ecology example—energy and order are not increasing. In the sense of evolution, as my original question was asking, it seems odd to say that a single-celled organism could ever become a multicellular organism even through the auspices of evolutionary genetics, as then the system would have a net increase in energy and order. Furthermore, it seems contradictory to the 2ndLT to say that a preceding generation of say a single celled organism will have less genetic information than the next. This again seems to be a net increase in energy and order. The 2ndLT seems to indicate that the next generation would have less information than the preceding one, through degeneracy and decay, so how would there ever be enough genetic information for a two or more celled organism? Maybe I am not phrasing this clearly yet, but do you see what I am trying to get at as far as contradiction?
thanks again for any input.
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Postby biostudent84 » Thu Dec 16, 2004 4:27 pm

I think you are mistaking information for energy. While, yes, as energy transfers, some is "lost"-usually in the form of waste heat. However, information is stored not unlike a computer--with the major difference being that computers store information in base 2 and genes store information in base 4 or base 20 (depending on how you look at it)--albiet a very adaptive and resilient computer.

As for the sheer amount of the information, remember that the more "advanced" (definetly the wrong word, but you know what I mean) an organism evolves, the more Junk DNA is in the genome. Humans, for example, have DNA with a composition of 90% Junk DNA. Some flowering plants can run as high as 99% Junk DNA. Bacteria molecules use far less...I apologize for not giving a number, I apparently forgot to bring that book with me to school =/
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Re: Evolution Questions

Postby natrgrrl » Mon Dec 20, 2004 10:47 pm

ERS wrote:Evolution is a topic everybody hears about (good, bad and everything in between), and it is fun to think about so why not!
ERS

I agree that evolution is fun to think about. Unfortunately, it seems to be a dividing enigma in America today.
My question is how evolution can be disproved.
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Postby ERS » Tue Dec 21, 2004 3:14 am

ah Kyle, you seem to be getting to the root of my quandry. Doesn't an increase in information result from an increase in energy?? It seems that they are tied. Meaning, how can you have more genetic information stored, without more sugar phosphate bonds etc.. formed, bonds being a "tie-up" or storage facility for energies and such???
Maybe, I am still confusing the two, but at some level they do seem reliant on each other.
further thoughts??
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Postby biostudent84 » Tue Dec 21, 2004 4:42 pm

WOW! I never thought of that before. That seriously will have me thinking for a while. Perhaps the energy requirement for the increased number of bonds is not enough to violate the Second Law...but still, there is SOME energy being wasted in maintaining all this Junk DNA, right?
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Postby brownpanda » Sun Dec 26, 2004 2:22 pm

as then the system would have a net increase in energy and order.


When we talk about order we are going into Complexity Theory. I'd better explain a bit about this....

Complex systems have a great many independent variables which interact with each other in many ways. These complex systems have the abilty to balance order and chaos - the edge of chaos. The diversity of the interactions between these vraibles allows complex systems to self-orgnaise - a thing which happens spontaneously.

(A famous example of self-organisation at work is French physicist's Benard's - he placed some liquid in a vessel and heated it. At the beginning, when temperature difference between the base and the top was low, heat was transferred by conducton and no macro-motion was observed. As the temperature difference between the base and the top increased, a thershold was reached and the movement in the liquid became chaotic. Suddenly, an ordered pattern appeared. A clear macro-movement was observed in rolls which were millions of times larger than themselves. When the liquid was contained in a round vessel, the motino of the rolls formed a hexagonal pattern on the surface of the liquid. This pattern is a result of hot liquid rising through the centre of the honeycomb cells, and the cooler liquid falling along thir walls. All this appears to eb the result of a force, but no such force is present....)

Complexity's greatest contribution has been to show that that Second Law is not the whole story. Complexity shows that not all systems tend towards disorder or entropy, and nature contains deep order which is believed to "emerge" naturally. So evolution is an example of life on the edge of chaos.

Disclaimer: I only read a book on this, and don't claim to be an expert of any sort. My info may be wrong.

By the way, it may help to read about self-organisation, chaos, and complexity theory on the net or in books.
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Postby biostudent84 » Sun Dec 26, 2004 6:17 pm

Which book do you speak of?

Also, how does this apply to the increasing quantity of DNA in the most recently evolved species?
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Postby junkyarddawg » Sun Dec 26, 2004 10:17 pm

Speaking of disproving evolution...what do any of you think about the new fossil find of the "minature" human? Even the pros are saying that evolutionary theory will have to be re-written. Sure throws a "monkey-wrench" (pun intended) into all of the previous versions doesn't it?
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Postby ERS » Sun Dec 26, 2004 10:19 pm

Panda,
You offered some interesting thoughts here, one of your statements was:

"Complexity shows that not all systems tend towards disorder or entropy, and nature contains deep order which is believed to "emerge" naturally."

can you elaborate on what kind of systems in nature follow this apparent breach of the 2LTD?? I am curious as to why a law would have an exception, and if there are actual examples in nature? You mentioned the organization of cooling liquid, but even that has its limits as eventually the system has a net loss of heat (i.e. cooling) which is still in line with the 2LTD.

Any thoughts Kyle? Has anyone seen any of this in their studies?
take care
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Postby biostudent84 » Mon Dec 27, 2004 1:42 am

I don't know...this idea hints on chaos theory, a theory that I've never put much stock in the first place.

The only violation that evolution violates the 2LTD is where there are more molecular bonds in DNA the more "advanced" an organism becomes. The sheer amount of information, I still say cannot be applied to 2LTD.

The only thing I can think of so far is that the excessive Junk DNA is still used, albiet only a small amount. DNA fragments have the ability to move around the chromosome, and some signals to begin reading the DNA are located up to 1,000 basepairs "upstream" of the actual site to be read. These other basepairs are part of this Junk DNA. Other than that, I've come across nothing yet that would explain this.
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