Originally Posted By: Orac
No person or scientist I know would ever class a Model T more advanced than a modern Ferrari and that is why your argument becomes word play no sensical.

But we're not talking about cars here - we're talking about species. And 'advanced' as species go is not as clear-cut as with cars. As I pointed out, so-called 'simple' single-celled organisms can have far more genes (i.e. parts) than us supposedly 'advanced' multicellulars; that also means that they have a theoretically larger capacity to respond to changes in the environment.

And 'advanced' or 'higher' is purely relative; which is the main point I was trying to make. A useful (i..e. 'advanced' adaptation in a human may very well be a detrimental feature in another organism. Colour vision is pretty advanced - unless you live 10km below the surface of the ocean...

Originally Posted By: Orac
The fact you consider by some word play you can invert and invent a criteria you can reverse that tells you that you are contriving an answer that noone would readily accept.

No, I was trying to apply your flawed example of cars to how biology works. Your analogy was false; ergo, it was difficult to make a good go of correcting it.

Originally Posted By: Orac
Your logic defies Entropy and in my area Quantum Mechanics your idea is in direct conflict with all it's central tenants. I know QM does not stop because something is alive and as QM has been much more rigorously tested than evolution I can say quite certainly you are wrong.

LOL, and you claim I'm scientifically ignorant. Evolution is by far one of the most tested scientific theories out there. Its not called the universal principal of biology for nothing.

Think of it this way - physicists are still seeking to understand some very basic aspects of QM; including how probabilistic phenomena at the quantum level translates into the deterministic behaviours we see in the macroworld. In contrast, the TOE is a unified and near-complete theory with great predictive ability. It has withstood over 150 years of scientific enquiry; and while the minutia has changed, the central tenants remain firm.

Continuing on....

Originally Posted By: Orac
QM states a system in a highly complex state is probably far from equilibrium and in a low entropy (improbable) state, where the equilibrium state would be simpler, less complex, and higher entropy.

Ahh, but herein is two serious problems:
1) With only a few exceptions, living organisms operate on physical principals which are not quantum in nature - the macromolicules of which we are comprised are too large to function in the probabilistic fashion of QM, do not display classical QM behaviours (discreteness, superposition, entanglement, etc), and instead obey the rules of classical physics. Since QM currently lacks a viable and accepted theory of how QM behaviours turn into the sorts of physics we see in the macro-world, it is unclear if you can apply the QM rules to biology - indeed, the general agreement in the field is you cannot.

Now before you get excited, let me point out that in a few rare cases quantum phenomena can be found in a small subset of isolated biological macromolciules - to date 3: photon anti-bunching in fluorescent proteins, quantum delocalization is one type of pigment, and a pseudo-quantum computing gate was constructed with nucleotides. The later is obviously a human construct, not an evolved one.

There has also been some discussion that olfactory receptors and photosynthesis may function through quantum tunnelling; the evidence there is circumstantial at best, with more conventional ligand-binding (olfactory) and electron-excitation-transport (photosynthesis) models remaining the de facto accepted interpretation at this time.

Problem 2, however, is a more serious one. Lets assume that the quantum definition of entropy holds true to the macrolevel. I'm unsure of which QM entropy measure you are referring to - your 'definition' (in quotes as you didn't provide anything that was very clear) doesn't match with any that I'm aware of (which, granted, is limited to Gibbs, von Newman & Shannons as used in information theory); but assuming it is based on similar principals, you ignored two key things:
a) it is not purely additive, and
b) entropy, in the QM systems I am aware of, increases only as you bias a system towards a subset of possible quantum states.

Biologically, the later kills much of your argument - the data we have shows that biological systems do not act at a quantum level, and ergo lack the capacity to drive quantum systems away from equilibrium.

Now, perhaps you meant in the context of information theory. But there again, your model fails - we know what information is required to produce living organisms (i.e. genomic contents), and we know there is no correlation between apparently complexity, and genome size/content. That leaves us with classical thermodynamics, which does not stipulate that more complex systems being more prone to failure.

Originally Posted By: Orac
You state multicellular is rare and the above explains why if you hadn't realised it before that is the reason. Hydrogen is the most abundant molecule in the universe because it is the most simple stable state same exact reason.

Again, your explanation fails. Hydrogen is the most abundant material in the universe for two reasons:
1) It comprised the majority of matter produced during the big bang, and
2) There has been insufficient stellar fusion to alter the balance towards larger atoms.

I'd point out that your argument fails at a most basic level - stable isotopes of many more 'complex' atom exist, and they are as stable as hydrogen. Ultimately, the stability of hydrogen or any other stable atoms is determined by the same thing - neutron or proton (if it exists) decay. Granted, H has not neutrons and thus is only limited to proton decay (if it exists). But that said, the half-life of a neutron in a stable atoms nucleus is on the order of 1015 to 1044 years - orders of magnitude older than or current universe (1010 years), meaning that neutron decay is incapable of accounting for the frequency of hydrogen - by many magnitudes of order.

Originally Posted By: Orac
Ethan Segeil did a really good article on it which you should read

http://scienceblogs.com/startswithabang/2013/01/02/what-we-learn-just-by-being-here/

I read it - it doesn't support your claim. Its a great article on the anthropic principle, but it in no way, shape or form supports your contention that simple = more stable or lower entropy. Indeed, the term 'entropy' doesn't even appear in the article.

It directly refutes your claim that hydrogen is more abundant because it is simpler and thus more stable, and correctly points out that hydrogen is primordial to the big bang, and thus the amount of non-hydrogen compounds is determined by rates of nucleosynthesis in stars.

Originally Posted By: Orac
The fallout of the stability decay of all chemicals due to entropic principles means that every atom or molecule in the human body is replaced every 7 to 10 years that is a huge cost to the organism and it is not optional because thats the decay constant of the molecules in the universe the more complex they are the shorter they survive. http://en.wikipedia.org/wiki/Radioactive_decay

Man, oh man, did you get that one wrong! It is not radioactive decay that determines the biological half-life of atoms in our bodies; rather it is the continued recycling of biological materials, combined with our continued uptake and loss of material, that produces the effect. For example, the four most common atoms in our bodies are hydrogen, carbon, oxygen and nitrogen. The least stable naturally occurring isotope of these are:
H3: half-life of 12.32 years
C14: half-life of 5730 years
N: no naturally existing unstable isotopes
O: no naturally existing unstable isotopes

So with no turnover, none of these atoms would decay enough to need total replacement in 10 years. It is only because of the continued building and degrading of biological materials that these end up being recycled as frequently as they are. Indeed, the average atom in your body only gets to be in a particular biomolicule (protein, lipid, etc) for a few days days before being recycled into something else. All of the water in your body is cycled every ~20 days...but not because of radiodecay!

Even taking the correct view of what is occurring - not radiodecay but rather biological recycling - it doen't support your position that it is 'harder' to be multicellular. Indeed, the recycling rate is inversely proportional to mass - i.e. the smaller you are, the more frequently you completely replace the constituent atoms in your cell/body. As you point out, in humans its about 10 years. In bacteria, its every 2-3 generations; thats as little as 1 hour for some rapidly growing bacteria!

Originally Posted By: Orac
If you want some scale of the problem in humans we are made up of 9.5% carbon which is around around 10^26 to 10^27 atoms (http://en.wikipedia.org/wiki/Composition_of_the_human_body).
The half life of carbon-14 is 1.808*10^11 seconds which equates to around 5000 decays per second that your body must replace. Potassium comes in next at around 4500 decays per second this is actually a routine lab test (http://sciencedemonstrations.fas.harvard...gecontent270775).

Again, a fatal flaw with your argument. These decays occur - but are rare. The vast majority of atom-replacement is simply due to metabolic cycling. But that said, all living organisms will experience the same decay rates, and thus have to replace a proportionate amount of their mass, and suffer a proportionate amount of damage. So if you had a 80kg mass of e coli, they'd experience the exact same burden as a 80kg man. That said, the burden is minute; a thousandth of a percent of the total cycled mass of the organism.

Originally Posted By: Orac
Your body is committed to these replacements every second of every day it is alive awake or asleep the entropic principles involved are simply massive.

Actually, the radiodecay you mention is a minute burden, compared to the regular entropic processes of our metabolism. But even there, simpler organisms have it harder. Metabolic rates scale inversely with mass, meaning the lowly e coli consumes far more energy, per mass, than a human - and thus disproportionately suffers the energetic and metabolic consequences of this.

Moreover, your self-claimed knowledge of entropy should make something quite important very obvious to you - to maintain that elevated metabolic rate means that e coli must continually keep itself farther out of thermodynamic equilibrium than a human (per mass, obviously). After all, the available energy in a system is directly determined by how far out of equilibrium the system is.

Indeed, e coli maintains a chemiosmotic potential (energy potential/thermodynamic disequlibrium) of -220mV, while our cells max out at -180mV and average -30 to -60mV.

Now, since entropy is a measure of energy in the system, which organism has the larger potential to loose energy?

So, contrary to all of your claims:
1) The QM theories of entropy probably don't apply to life,
2) The QM theories of entropy I am aware of (including QM-associated information theory) do not dictate simpler = lower entropy; or indeed, that there is any link between complexity and entropy.
3) Radiodecay is not a significant source of atom turn-over in living organisms, an impacts all organisms equally by mass, and lastly but most importantly,
4) As measured by classical physics, smaller organisms maintain a higher degree of thermodynamic disequilibrium than do larger organisms; i.e. entropy is larger in their lives.


Originally Posted By: Orac

As an aside when people talk about Silicon based life forms these decay rates are the reasons against it. The half life of Carbon-14 is 5700 years the half life of Silicon-32 is a mere 170 years. So if humans were silicon based life forms the entropic overhead is orders of magnitude higher again than a carbon based life form just based on the increased turn over for the organism to stay alive.

Again, completely wrong. Silicon life is considered unlikely for chemical reasons, not radioactive ones. This post is already over-long, so here's a paper. Long story short - it is exceedingly rare in the universe (relative to carbon) and due to it size and bonding characteristics, is incapable of producing the same diversity of molecules as is carbon (and thus is unlikely to be able to support the formation of life-like chemistries).

Originally Posted By: Orac
Ultimately everything dies because it loses the battle to this law

Wow, I mean wow. This is so wrong I have to double-face-palm myself.

Firstly, not everything dies. If this were so, no organism that reproduces by binary fusion would exist. Any such living organism today are merely the current form of an organisms which has lived and replicated continually since the first life arose on earth. At no point in time did the organism die - it divided, it changed, but there is no death between the first cell and todays existing cells. Indeed, for these kinds of organisms the concepts of death and birth don't even work; which of the daughter cells is the mother, which the child? The answer is, of course, 'both and neither'. Death, for non-sexually reproducing organisms = extinction.

As for us, you are completely wrong on why we die. It is true that radiodecay of internal atoms does cause some biological issues - namely, it occasionally causes mutation. However, that is not why we die. Why we die is due to a number of factors - mutations are one; but even there, radiodecay of atoms in our bodies account for only ~1:20 mutations. The rest are replication errors or due to chemical damage. Far more involved in our ageing and eventual death are three processes - loss of telomere DNA due to incomplete DNA replication during cell division, mitochondrial exhaustion, and the accumulation of protein & lipid aggregates (these damage our cells). The latter (in theory) could actually be helped by radiodecay - anything that breaks up these aggregates would allow for their clearance.

Originally Posted By: Orac
and even the universe itself is not excluded from it. If your selective forces were stronger than QM radioactive decay laws you would have species extinctions on average shorter than a few years and by your own comments its thousands of years.

While your QM premise is false, I'm confused by your logic here. Selection need not cause extinction to exist, nor is extinction a measure of the strength of selection. So how you equated the two is a bit of a mystery - as is your conclusion.

Originally Posted By: Orac
Your whole argument thus falls to the science axe of Occam's razor.

Occam's razor only works if the facts used are true. Since most of your claims were false, so was the inevitable conclusion.

Bryan


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