Wikipedia:Reference desk/Archives/Science/2013 August 8

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

August 8

Water-soluble material ?

Is there a water-soluble material which is not soluble in a solution of sodium hypochlorite (chlorine bleach) dissolved in methanol (alcohol) ? It can be only slightly water soluble, but can't be at all soluble in alcohol or bleach. If so, what is it/are they ? If not, why not ?

Also, mixing chlorine bleach with ammonia is dangerous, as it produces chlorine gas. Is there any such danger from mixing it with methanol, or any other dangers ? StuRat (talk) 06:39, 8 August 2013 (UTC)

Well chlorine + ethanol produces chloroform, heat and then chlorine gas once hot, so don't do this. Ammonia and chlorine can make chloramine or hydrazine, neither a good idea. I don't think that methanol and bleach are a good combo either! Graeme Bartlett (talk) 11:16, 8 August 2013 (UTC)

I see. Can bleach be safely diluted in anything else besides water ? StuRat (talk) 16:23, 8 August 2013 (UTC)

What's your goal here? Might be many possible solutions to "what you're trying to accomplish" other than as you've phrased it, and also your application may limit the solutions (ha!) that might answer your general question. DMacks (talk) 17:20, 8 August 2013 (UTC)

It's to solve a problem with using bleach in the washing machine. I like that it's inexpensive, whitens, and sterilizes clothes, but don't like that if it splashes on your clothes they are ruined and if it splashes in your eyes you are in serious trouble, and breathing it is bad for your lungs. So, my idea is to have a small quantity contained inside a water soluble wrapper, which then dissolves during agitation, eliminating any possibility of it splashing, and hopefully only creating bleach fumes after you are out of range. StuRat (talk) 04:54, 9 August 2013 (UTC)

Well you could have it as a solid powder, perhaps diluted with a harmless things like sodium sulfate. Then you could coat little balls of that in a slightly soluble coat of something. Splash should not be a problem, just when it dissolves it will be concentrated at first. Graeme Bartlett (talk) 11:58, 9 August 2013 (UTC)

NaOCl doesn't solidify well (at least not stably, safely, cheaply, and usefully:). But there are lots of other types of bleaches that do. Calcium hypochlorite is commonly used as a granular solid alternative to sodium-hypochlorite solutions, but takes a while to dissolve. I vaguely remember that it has different pH effects, but the swimming pools where I worked had such high bather loads and other environmental situations, we was hard to notice the OCl^– source difference as having other effects. There are also stabilized forms of NaOCl that are solid (pre-reacted with isocyanuric acid), and also other sources of the key ion (via chloramine-T)--lots of waste mass and probably not likely as economical. The idea you're proposing is akin to microencapsulation (probably easier to do QA and handle than a single portion of a liquid, maybe we could call that "macroencapsulation"?). There are already such products available (or at least patented and discussed if you google it). DMacks (talk) 15:37, 9 August 2013 (UTC)

Thanks. Sounds like calcium hypochlorite clumps might be the way to go. How much would be equivalent to a cup of bleach (6% sodium hypochlorite) ? And how long would it take to dissolve in the agitation of a washing machine ? Also, are there any special handling instructions for it ? Is the dust toxic ? StuRat (talk) 06:34, 10 August 2013 (UTC)

Cancer

Is cancer partly genetic as some families don't have many cancer sufferers compared to others? — Preceding unsigned comment added by Clover345 (talk • contribs) 09:35, 8 August 2013 (UTC)

Definitely, and many of the genes responsible have been identified, such as the BRCA mutation. Diet, exercise and environmental exposure to carcinogens are other major factors which affect cancer rates. StuRat (talk) 10:27, 8 August 2013 (UTC)

Do you have any source about exercise as a carcinogen factor? 79.156.170.130 (talk) 12:27, 8 August 2013 (UTC)

It is lack of exercise that is the factor: see Cancer#Diet and exercise. AndyTheGrump (talk) 12:34, 8 August 2013 (UTC)

LOL, yes, I would have thought that was obvious, but have appended to my original response to make it clear. StuRat (talk) 16:19, 8 August 2013 (UTC)

structure of element 171

See Fricke [1] (relativistic). It's probably a solid at STP, right? Seeing as I have so far failed to find any reliable sources on the possible structure, can someone give their predictions here (with thoroughly citable reasoning? – especially polyatomic vs. diatomic.) Thanks. Double sharp (talk) 11:40, 8 August 2013 (UTC)

It is impossible to answer, current theory predicts that it should not even exist. Due to the requirement of electrons to have a speed exceeding the speed of light. What you're asking is comparable to asking "If balloons were conscious beings, what would they say?" Are you sure that you're referring to unseptunium, or do you mean ununseptium? as that would change everything. Plasmic Physics (talk) 04:05, 9 August 2013 (UTC)

I do mean 171, but would not mind also receiving info about 117. Element 137 is not really a problem; if you take into account that the nucleus is not a point, then you only get problems at 173 (see Periodic table#Element with the highest possible atomic number). Even then the problems might not cause and end to the periodic table.

(Naturally, please assume there is some unknown metastable isotope, or else it's a rather pointless question) Double sharp (talk) 04:31, 9 August 2013 (UTC)

It is still difficult to predict, considering that we don't know how the periodic table is structured beyond the seventh period - the rate of change in trends with respect to period may contain an unknown point of inflexion. Plasmic Physics (talk) 05:40, 9 August 2013 (UTC)

The article says that 171⁻ should be a hard base like Cl⁻ and that 171 should have an electron affinity of 3.0 eV. Does that help in predicting? Double sharp (talk) 06:51, 9 August 2013 (UTC)

I that sounds highly dubious considering the decreasing stability of the halide ions with respect to the period. Astatine is already the more stable in the 1+ state than in 1- state. PS I can't open the link. Plasmic Physics (talk) 07:22, 9 August 2013 (UTC)

relativistic effect! np_1/2np_3/2 subshells are destabilized, but the 9th period fills 9s 9p_1/2 (1st two electrons of p) 8p_3/2 (last four electrons of p), which is apparently stabilized to the point that it behaves like the 2p or 3p subshell. (summarizing the rationale in the link for you) Double sharp (talk) 08:01, 9 August 2013 (UTC)

Ok, so the trend does an about face, like what I've mentioned at 05:40? In that case, it would depend on how strong that stabilising effect is. Plasmic Physics (talk) 10:18, 9 August 2013 (UTC)

I'm just pulling this out of a hat, but I predict that it will be a highly reactive, grey-coloured, monoatomic, volatile metal, in which the 3+ state is most stable followed by the 1- and 1+ states. Possibly forming a variety of coloured suboxides. Possibly having an electronegativity between that of sodium and lithium. Plasmic Physics (talk) 12:20, 9 August 2013 (UTC)

reading his description, would personally not call it a metal... Double sharp (talk) 12:55, 9 August 2013 (UTC)

Perhaps a weak metal like aluminium, or maybe a poor metal like thallium? Plasmic Physics (talk) 13:05, 9 August 2013 (UTC)

Yet if he's right and the trend does do an about face, then I have some difficulty seeing how M⁻ (M = metal) could be a base like Cl⁻...also he calls H(171) a hydrogen halide, which implies to me that it would be more like iodine (given the similar electronegativity). What would that imply? Double sharp (talk) 13:18, 9 August 2013 (UTC)

I reckon it would not be so dramatic, it would probably be between iodine and astatine (closer to astatine), possibly with a 70 degree Celsius melting point? Plasmic Physics (talk) 13:32, 9 August 2013 (UTC)

OK, and structure-wise? (iodine is only just diatomic, could this have a polyatomic structure? diatomic At could also be stabilized in solid form due to intralayer bonding just like I, so 171 could plausibly be diatomic, but I can see it not happening too!) Double sharp (talk) 06:27, 10 August 2013 (UTC)

also interested: electronegativity? band structure? packing efficiency? Goldhammer-Herzfeld criterion? (bcos I wanna see if it's going to be a metalloid or a nonmetal, although I suppose if he calls it a halogen then it's probably nonmetallic enough to be called a nonmetal like iodine or astatine) Double sharp (talk) 06:38, 10 August 2013 (UTC)

The social structure of ants, bees etc. and the evolutionary explanation to their sexual reproduction

Colonies of ants, bees etc. have a single individual (the queen) that procreates. Is there a name to this social structure? I guess it would be related (but not identical) to eusociality.

Also, these organisms have sexual reproduction, but I can't think of any evolutionary justification to it. As far as I understand the Red Queen hypothesis doesn't apply because the queen and the male that impregnates her are siblings. What's the explanation?

Thanks, 84.109.248.221 (talk) 11:57, 8 August 2013 (UTC)

See kin selection and evolution of eusociality. Also, you might find "Darwin's special difficulty: the evolution of “neuter insects” and current theory" interesting. Sean.hoyland - talk 12:05, 8 August 2013 (UTC)

When only a single queen is present, the colony is called monogynous, and when many fertile queens are present, the colony is polygynous. These habits do not clearly break along the pre-social to eusocial continuum, and some species have colonies of both types. Note that a queen is not usually inseminated by a sibling male. Many species (e.g. honeybees, fire ants, etc) have massive nuptial flights, where all the drones and virgin queens go out at once to play. The evolution of eusociality is an ongoing topic of research, but it is commonly agreed that Haplodiploidy has plaid a role in the social insects. However, haplodiploidy is not a necessary condition, as there are eusocial, monogynous mammals (naked mole rats), and haplodiploid solitary wasps. The classic text on all things social insect is The Insect Societies, by E. O. Wilson, [2], and I highly recommend it to any interested parties. SemanticMantis (talk) 13:30, 8 August 2013 (UTC)

Are all flames produced by fire?

Can flames be produced through any other source? Like when an atomic bomb goes off and you see the fireball, are those flames being produced through simple heating of the atmosphere via the nuclear products or is something actually burning (redox) that produces those flames? ScienceApe (talk) 15:16, 8 August 2013 (UTC)

Air can be heated to incandescence without a chemical combustion reaction. If you accept the definition of flame provided in the leader to our article, though, the word "flame" refers to that type of incandescent air related to fire (that is, ordinary chemical combustion). So, this is really just a question of how you want to use the word.

As far as I know, Atomic Fireballs are flavored with cinnamon, and have neither flame nor fire. Nimur (talk) 15:58, 8 August 2013 (UTC)

Though if you want to get pedantic, the cinnamon plant grew with much help from the Calvin cycle, which involves small heat-producing reactions. Also, unless advertising lies, many cinnamon candies cause smoke to emit from the ears and flames from the mouth. InedibleHulk (talk) 08:49, 9 August 2013 (UTC)

Incandescence by definition involves the emission of visible light. Heating air to incandescence? I don't think so. To emit light, a substance must be an effective black body radiator for light. All the gasses in air, Nitrogen, oxygen, argon, etc) are fully transparent. Flames from burning hydrocarbons emit visible light mostly because they contain carbon, which is one of the best black body radiators (not transparent) known. The fireball following atomic bomb detonation contains all manner of compounds from the earth thrown up by the blast, some set alight, some just heated enought to emit as black bodies without combustion. The explosion itself emits visible light directly. You can heat the gasses of air hot enough to ionise them (well above black body incandescence temperature), which will produce light, but then you no longer have air. It's a bit like saying let's heat water to incandescence. You won't have water any more longer before you get hot enough for ionisation. It will split into H2 and O2 longer before, and further into monoatomic hydrogen and oxygen at lower theperatures. And ionisation always involves emision at specific wavelengths, unlike black body radiation, which is essentially random noise (all wavelengths). 1.122.236.146 (talk) 16:20, 8 August 2013 (UTC)

1.122.236.146_(Geolocate), you're seriously suggesting that atmospheric air can not incandesce when heated, because it's transparent at room temperature? Although that's an interesting piece of thought-experiment science-fiction, it's totally false. Air - including nitrogen - incandesces when heated, and emits visible light whenever its temperature is high enough. You might want to re-read black-body radiation and incandescence. Nimur (talk) 16:30, 8 August 2013 (UTC)

Yeah - and if you doubt it - I guarantee that you've seen it with your own eyes. The air glows during a lightning strike. There are no other substances introduced into the path of the lightning bolt - so it must be the air that's glowing. Indeed the air forms a plasma with a core temperature around 50,000 K, causing it to glow with a blue-white color.

The problem with our OP's question is that the terms "Fire" and "Flame" are inextricably entangled and confused - and not very well defined in scientific terms. Is the sun "on fire"? Are there "flames" coming out of the surface? What about molten steel? Are electrical sparks a kind of flame?

Our dictionaries fail us at these times - so answering a question that's a bout mere words in a scientific manner is kinda silly. Put it this way - there are certainly ways in which gaseous and finely divided airborne particulate substances can be made to glow brightly in the absence of any vigorous oxidation processes. If the former is "flame" and the latter "fire" - then yes. SteveBaker (talk) 20:08, 8 August 2013 (UTC)

Nimur and Steve, you didn't read carefully what I wrote. You missed the distinction between incandescense and spectral emission. Gasses such as N2, O2, Ar, Co2, are fully transparent at ALL temperatures at which they can exist. The dissociated forms N, and O are also fully transparent at all temperatures for which they can exist. Re lighning strike emission, you said it yourself: Ionisation occurs - it is not N2, O2, and Ar etc when it glows. It's not even N and O. The emission from ionisation is spectral and not black body. This spectral emission is not from air, not black body, and not flame or fire. It's true that many terms in chemistry are not standardised and precise as terms in other sciences are. However, it is generally undertstood that flame is the visible gaseous part of a fire, caused by and exothermic reaction. My answer above works with this definition. See the Wikipedia article on flame, especially the first sentence, which Nimur was clearly aware off, even though he stated incorrectly that air can be heated to incandescence. Incandescence IS by definition that emission that is thermal radiation (noise) and is not spectral - you can check this yourself. Saying air can be heated to incandescence is much like saying aluminium can be heated to incandescence. You can certainly ionise Al and make it emit spectral lines, but you can't make it glow with heat like iron does. 1.122.175.140 (talk) 01:25, 9 August 2013 (UTC)

Adding heat is a method to ionize atoms in some materials. And whenever ionization happens, spectral emission might also happen. But those spectral emission lines superimpose on top of a blackbody emission curve. All materials emit thermal radiation; and the spectrum of thermal radiation is characterized as a blackbody spectrum. Hot materials - even "inert" substances like noble gases and non-reactive metals - emit visible light. Why do you believe that aluminum can't emit blackbody radiation in the visible spectrum? First of all, aluminum doesn't vaporize or ionize until it gets much hotter than necessary to emit visible light. And even still - supposing a different material does vaporize or ionize - those effects don't cancel out the blackbody emission. At best, ionization causes spectral emission lines that superimpose on top of the continuous thermal radiation spectrum. A good example is the solar spectrum: the sun, as a highly ionized plasma, emits light at visible and other wavelengths - and its spectrum contains discrete lines imposed on top of a continuous blackbody pattern. Nimur (talk) 04:00, 9 August 2013 (UTC)

No reason to continue this discussion, Keit/Ratbone etc is a banned editor per WP:RESTRICT Nil Einne (talk) 08:38, 9 August 2013 (UTC)
The following discussion has been closed. Please do not modify it.
Ok, let's take all your points, one by one, and examinine them in the context of ScienceApe's question, and in the context of my responses to you and Steve above. Adding heat is a method to ionise atoms: Yes, of course. 100% correct, and nothing I said is in contradiction to that. If you heat some air enough to ionise the atoms, you no longer have air. You have instead the component atoms in ionised form, with all manner of completely different properties. Whenever ionisation happens, spectral emission might also happen: No real problem here. Strictly speaking, it will happen, but some or all of the lines may not occur in the visible range, depending on the electron orbital structure. Spectral emision lines superimpose on black body emission: Yes, of course. Nothing I said is in contradiction to that either. All materials emit thermal radiation with a spectrum characterised as blackbody radiation. Strictly speaking, all materials DO emit black body radiation. However, and this where you've gone astray, the emission from any real substance is always less than the theoretical blackbody emission curve. Carbon is an example of a very good black body emitter. Over a wide range of temperatures, its emission vs wavelength curve approximates the theoretical black body curve very closely. Aluminium is an example of a not very good black body radiator. Its emission vs wavelength curve shows very markedly reduced output in the visible spectrum, and reduced emission at infrared. As any welder or foundry worker can tell you, you simply can't get aluminium to visibly glow by heating it. In contrast, iron, which is a good black body emittor at moderate temperatures and above, glows readily. This is important in both arc welding and oxy-acetylene welding. Note that aluminium melts at 933 K; steels at 1100 to 1500 K or so; visible black body light starts at around 800 depending on ambient lighting. So, according to you, when aluminium melts, it should be glowing. It certainly does not. Welders are taught how to assess the temperature of hot steel quite accurately by its emission colour (deep red thru to yellow at metal working temperatures). You just can't do this with aluminium - we use tricks like wiping it with a thin pine stick, wiping it with soap and noting how quick the soap turns bown, and the like. There is a "trick" for making any substance into a dramatically better black body radiator though - form it into a cavity radiator. This is a way to improve emissivity by increasing the colour density per unit area, and is often used as a simple temperature indicator in furnaces and kilns. Aluminium doesn't vaporise or ionise until it is much hotter than necessary for black body radition: Well, since it vaporises at ~ 2800 K, and visible radiation from an ideal black body starts as a dull red at around 800 K depending on masking of ambient lighting, that is on the face of it true. Trouble is, aluminium is NOT anywhere near an ideal black body radiator. It's not black, it's shiny and white. — Preceding unsigned comment added by 1.122.206.136 (talk) 08:16, 9 August 2013 (UTC) Vaporisation and ionisation do not cancel out (stop??) black body radiation: This has no impact on what I said before. It is sort of right. In practice, transparency and colour of a substance is often different in the gas form than in the liquid or solid form though. Where this is the case, efficiency as a black body radiator is affected, more so at certain wavelengths. The rest of your points are a re-iteration of the points I've gone through. You have it all pretty right, but you have assumed that all substances are perfect black body radiators. They are not. Real substances show overall emission less than 100% of the perfect back body, and real substances are good (not perfect) at some parts of the EM spectrum and poor at other parts. The black body emission curve is the limiting case that nothing real can exceed. Substances that are dark coloured and non transparent are good black body emittors in the visible spectrum. Conversely, substances that are fully transparent to the eye (and thus by definition are not coloured) are poor black body emittors in the visible spectrum. They may, of course, and most often will be, good black body emittors at non-visible wavelengths. Nothing I said before violetes this. Why do I believe that aluminium won't glow with heat? Two reasons: 1) years of experience that includes welding and casting Al and its alloys; 2) Kirchoff's Law of Thermal Radiation. Essentially, this is a Law of Reciprocity. Substances than absorb poorly at a given band of wavelengths are poor emittors at those same wavelengths. If there is zero absorbtion (ie substance is transparent) then it cannot thermally emit. — Preceding unsigned comment added by 1.122.206.136 (talk) 07:22, 9 August 2013 (UTC) 1.122.206.136 (talk) 06:24, 9 August 2013 (UTC) Not attempting to refute your point, just curious: What about glass? It's near transparent, but still glows when heated. MChesterMC (talk) 08:21, 9 August 2013 (UTC)

You can get flames by burning various substances in chlorine gas, so an oxygen atmosphere is not necessary. μηδείς (talk) 22:00, 8 August 2013 (UTC)

And apparently, Kiet/Rabone has discovered another way to produce flames...but not without getting fire. SteveBaker (talk) 14:30, 9 August 2013 (UTC)

I avoided answering this because I don't know how transparent gas really is, but there has to be some limit. There are molecular orbitals and higher molecular orbitals, so there have to be some emissions/absorptions, right? (Looking this up quickly it looks like [3] page 9 gives a whole range of frequencies in the visual spectrum. I'd wonder how I see through it at all now... Wnt (talk) 17:49, 9 August 2013 (UTC)

The link you supplied seems to be defunct - it's just a blank page. However, it seems from your wording, and the link address, that you are talking about spectral emission/absorption. When we talk about something being transparent, we are not talking about no spectral emission/absorption. We are talking about no broadband black body emission/absorption. A fully transparent substance can emit spectral lines even though it is transparent, but it cannot act as a black body and emit a broad band. A non fully transparent substance can emit both broad band and spectral lines, as Nimur has pointed out. In a sense, a gas only absorbing specific spectral lines is not fully transparent as then those specific frequencies/wavelengths are not passing right through it. However, the eye will not detect it unless the ambient illumination comprises only those precise wavelengths. Under white light or near-white light the substance will appear fully transparent, and will be classified as such. 124.182.50.53 (talk) 02:53, 10 August 2013 (UTC)

mathematical proof to evolution

Should it be possible, in principle, to proof mathematically that mechanisms like natural selection, sexual selection etc, combined with mutation rate like the rate found in nature, can create the diversity and complexity of life as we see it? did researches tried to construct such proofs? thanks, 94.159.164.161 (talk) 19:27, 8 August 2013 (UTC)

Evolution is certainly a "self-evident" logical consequence of systems that

1. Replicate themselves on the basis of a design embedded as a part of themselves.
2. Compete for limited resources of some kind - without which they cannot replicate.
3. Have occasional errors in the replication process.

If those three conditions are satisfied, then there is no way that evolution cannot occur because:

1. The errors will result in some differences in the design of some individuals relative to their parents.
2. The competition for resources will result in the numbers of accidentally improved designs increasing.
3. Result in a gradual improvement in the design.

Turning that into the language of mathematics ought not to be difficult.

Life (as we know it) uses DNA as the "embedded design", has to compete for nutrition and possibly other things, and DNA is subject to random mutations and transcription errors. Hence life evolves. QED.

Very minimal computer-based systems (See: Artificial life) bearing just those three basic characteristics have been shown to evolve every bit as strongly as "real" living things and Genetic algorithms are routinely used by software engineers to solve certain sorts of programming problems using an "evolutionary" approach.

SteveBaker (talk) 19:51, 8 August 2013 (UTC)

See "Fine-tuned Universe".—Wavelength (talk) 20:11, 8 August 2013 (UTC)

No, don't see Fine-tuned Universe since it has nothing to do with the question.

See Evolutionary dynamics and Evolutionary game theory instead.

Dauto (talk) 20:32, 8 August 2013 (UTC)

• There isn't really any need for a mathematical proof. To people who understand genetics, it is completely obvious that evolution will occur if enough time is allowed. The problem is that people who have doubts about evolution hardly ever have any knowledge of genetics, so it isn't obvious to them. Looie496 (talk) 21:16, 8 August 2013 (UTC)

You may be right in this case, because you'd only be proving things about a model anyway, not about the real world of biology. But, in general, "obviousness" is no reason not to prove things mathematically. For instance, certain "obvious" facts are actually wrong, and other "obvious" results are very rather difficult to prove, e.g. the Jordan curve theorem. In that case, the value of the proof is not only that it gives us certainty of the result, but the methods developed for that proof are also useful to prove other, less obvious things. SemanticMantis (talk) 21:24, 8 August 2013 (UTC)

• No. The premise is a corollary of reductionism, that everything (and its' explanations) reduces to the laws of physics expressed in a few equations and the original state of the universe. But There are loads of concepts which in no way can be reduced to the laws of physics: in This is Biology, Ernst Mayr gives an off-the-cuff list of two dozen concepts like ecological niche, sympatric speciation, and sexual selection which are emergent and cannot be reduced to any chemical description or physical laws. See [[4]]. To even pretend that one could, from bare premises, predict a pouched mammal that eats only Eucalyptus leaves or the existence of such organisms as Vampyroteuthis is intellectual hubris. μηδείς (talk) 21:54, 8 August 2013 (UTC)

But if you have some emergent phenomena then these are (to some degree) independent of the underlying model, then it is possible (in principle) to predict these phenomena. The issue is simply that a higher level description in terms of the emergent phenomena captures the relevant dynamics of the system. So, if a lion is chasing a wildebeest, the dynamics of this system is appropriately described at the level of these animals. You could describe everything in terms of atoms, but to make the lion and wildebeest visible, you have to integrate out the lower level dynamics, and then invoke the definition of the higher level concepts in terms of the lower level description. For some systems one can actually perform such calculations within some appropriate approximation, such methods are known as "renormalization group methods".

These methods have been particularly successful in explaining the thermodynamic propreties of substances near the critical point where phase transitions happen. These thermodynamic properties do not exist at the level of atoms (they are emergent phenomena), yet one can explain them starting form a model about the atoms and their interactions. It was always believed to be impossible to do so (because the thermodynanic properties only become well defined in a regime that is infinitely far removed from the scale that your model applies to, so it seems that it would require an infinite computational effort to compute them), until Wilson showed in the early 1970s that one can in fact quite easily compute the quantites of interest.

So, I would not give up on the idea of deriving biological behavior that is to some degree universal from the underlying laws of physics. Count Iblis (talk) 23:37, 8 August 2013 (UTC)

The whole purpose of the concept of emergence is precisely to deal with higher level phenomena which are not able to be described or hence predicted from lower level phenomena. I strongly recommend reading Mayr, who formulated the biological species concept (another phenomenon which is based on the interactions of populations and cannot be predicted from physics or chemistry) and who as the "Dean of biology" was the voice of 20th century consensus. Mayr criticised S J Gould, but far less than he did reductionists like Richard Dawkins. Gould's emphasis on radical biological contingency reveals another concept that argues against such physiochemical prediction. Read Gould's description of the lone German Shepard dog which over a period of six weeks almost sent the Kiwi bird into extinction. 'Bully for Brontosaurus PDF'. That's hardly something that can be explained or described in terms of masses and velocities of C, H, N, O, Mg, & P. μηδείς (talk) 00:56, 9 August 2013 (UTC)

See http://www.darwinismrefuted.com/molecular_biology_04.html

—Wavelength (talk) 01:32, 9 August 2013 (UTC)

See our article on the self-published author of that website, Adnan Oktar. μηδείς (talk) 01:44, 9 August 2013 (UTC)

Thank you for directing me to that article. I had not previously investigated the website to find out its author. At the bottom of http://www.darwinismrefuted.com, the expression "About the Author" is a link to http://www.harunyahya.com/bilgi/yazarHakkinda, titled "About the Author".

—Wavelength (talk) 02:48, 9 August 2013 (UTC)

The OP's question is in the same vein as one asked some weeks or months ago, about whether you could predict the evolution of a language. The answer to both questions is, no, you can't, because no model can take into account all the random factors that influence entities in the universe. As a simple example, consider hurricane landfall predictions. They don't tell you where it's going to land, they give you probabilities. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:30, 9 August 2013 (UTC)

Conway's Game of Life has emergent patterns though the individual cells have specific rules. If you played out the game with many moles of automata for billions of years, maybe, though no H. sapiens could ever keep track or follow the calculations, you'd see Dilbert contemplating free will. 75.75.42.89 (talk) 03:45, 9 August 2013 (UTC)

Life shows amazing emergent properties, and it is (in theory) Turing-complete. But it not a good analogue to evolution, since it is fully deterministic. You would need to introduce some small randomness to promote "real" evolution. --Stephan Schulz (talk) 03:57, 9 August 2013 (UTC)

It's not just "in theory" that Life is Turing-complete. Someone built an actual, working, Turing engine within the game: http://rendell-attic.org/gol/tm.htm SteveBaker (talk) 14:11, 9 August 2013 (UTC)

Do the emergent properties instantly disappear when you introduce automata rules that factor in some small randomness (e.g., if the cell above you is black, and a random number generated is greater than 0.8, do X)? 75.75.42.89 (talk) 11:00, 9 August 2013 (UTC)

No. There are stochastic cellular automatas (although our article is rather brief), and they show similar emergent behaviour. Here is a hunter-prey model based on a stochastic cellular automaton. It's a rather small grid and simple ruleset, but it already shows interesting behaviour. --Stephan Schulz (talk) 11:24, 9 August 2013 (UTC)

Even without true randomness, you could produce evolution in Conways' game of life by having devices that pseudo-randomly shot out objects (like maybe a "glider") that would act like a cosmic ray in the real world to disrupt some self-replicating system and induce mutation.

Here is (roughly) one way to do that:

• Because Life is "turing-complete" you could use this Turing machine to run an arbitrary computer program. (The "Church-Turing thesis" says that this is possible because all Turing-complete machines are equivalent).
• Hence we can write Pseudorandom number generators with sequences of arbitary length - including lengths that are longer than the life of the simulated universe.
• Self-replicating structures do exist in Life (for example this one - which replicates itself every 34 million generations (that's actually kinda fast for such things!). Nobody thinks this is the best possible replicator because it's the first one that anyone ever came up with - so there is certainly room for improvement.
• The replicator uses an "instruction tape" structure - which is (in effect) it's DNA.
• We could presumably use the output of the turing machine to pseudo-randomly shoot gliders at the tape structure to modify it.
• This would cause mutations of the original structure as it replicates itself.
• Most of the time, this would cause the generated replicator to fail.
• But given enough time, a viable - but somewhat different replicator would come out of that.
• Most of the time, those would be worse at replicating than the original one.
• But given enough time, a better replicator would eventually emerge.
• However, for evolution to occur, there has to be some kind of limited resource to compete over - or else the less-efficient replicators won't die out.
• The difficult part of "Life" is that the only resource that objects can compete for is space - and even that is infinite in an idealized version of the game. However, there is a "speed of light" limitation in Life - the maximum speed that any object can move is limited. Hence, from a single replicator and a single source of disruption there is a rapidly growing - but still finite - amount of space available for our replicators to grow into...that is space that they can compete over. But there is no equivalent of "mass" or "energy" in a life simulator. That's going to make evolution happen a bit weirdly...but it can still happen.

But if a system as simple as "Life" can exhibit evolution, then surely there can be no doubt that our universe, with it's vastly richer set of "rules", can also do so...particularly because we know that it's possible to implement Conway's game of life inside our universe.

SteveBaker (talk) 14:06, 9 August 2013 (UTC)

It may not prove evolution, but Homer Simpson (after an accident left him briefly intelligent) disproved God. Take it with a grain of salt, perhaps. InedibleHulk (talk) 11:05, 9 August 2013 (UTC)

And then, as a fitting punishment, God returned Homer to his former condition. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:28, 9 August 2013 (UTC)

That was Moe's work. "You know when your dog's having a bad dream? That's who I pray to." InedibleHulk (talk) 18:04, 9 August 2013 (UTC)

Is there some sort of proof a random element is either necessary for or indeed would lead to evolution in the sense of natural selection? I find both claims horribly dubious, and have to laugh at the return to Epicurus's clinamen. μηδείς (talk) 00:35, 10 August 2013 (UTC)

Randomness is what provides the material for natural selection to work on. It's "Evolution through random mutation and natural selection" - natural selection is the non-random part. Yes, you need some source of randomness to inject information into the system (unless you assume an open system with some kind of input from the outside - but in that case, see infinite regression). You don't need to go back to Epicurus. Quantum mechanics is enough. --Stephan Schulz (talk) 04:40, 10 August 2013 (UTC)

No, randomness there simply means without regard to some predetermined end, like mutations that don't all occur with the predetermined goal of turning dinosaurs into birds. Such mutations have no preset goal in mind--in that way they are random. But their cause could be regular--every 1,000th base pair might mutate to the next base on the right handed side, A>C>G>T>A starting with the date of the year the proto-chicken's born on. What causes the mutation need not be random for its effect on the chicken to be random. μηδείς (talk) 05:15, 10 August 2013 (UTC)

Well, that depends on what you use as the state for your deterministic system of mutations. The strength of random mutation is that different identical copies of the genome undergo different changes, thus exploring a much larger space of possibilities. If you systematically mutate the genome, starting with a single individual, then all generation X members will have the same genetic markup. Moreover, you might get stuck in a local fitness maximum much easier - since there is only one possible mutation, if that one does not improve fitness, you are stuck. If you do what Steve is suggesting (having a sufficiently large number of pseudo-random numbers and use them to drive evolution), then yes, you can be deterministic. But then the information you need is already in the pseudo-random sequence - see Information theory. --Stephan Schulz (talk) 14:58, 10 August 2013 (UTC)

What is needed is some means for the DNA of the offspring to have some probability of being different from either of the parents...a mutation. It is true that without some kind of relatively unpredictable mutation, all creatures on Earth would be genetically identical...and if that's the case then there is no evolution.

But that variation could still occur in an entirely deterministic universe. A deterministic universe could still shower the earth with cosmic rays, some of which would cause mutations - and so long as they originated in a sufficiently complicated manner - their actions would be indistinguishable from random mutations. All that's really needed is that all parts of the DNA strand can be changed by the process and that the change isn't 100% consistent from one generation to the next.

Any mathematically chaotic system can produce enough randomness to do that. Weather patterns, for example, are essentially unpredictable - even in a deterministic universe. If a single-celled animal's DNA mutated every time it survived being struck by lightning - then that would suffice for evolution to take place.

In computer simulations of evolution, we have no source of truly random numbers (the computer program is deterministic) - but we can use a Pseudorandom number generator (PRNG) to generate numbers that appear to be random until the sequence eventually repeats. We could, for example, use a million bit PRNG with a repetition period of around 2^999,999 and use the output of that to determine which C,A,G or T in the DNA should be switched to a different letter whenever a bacterium reproduced. With a few billion letters to choose between, you'd have enough randomness to produce one mutation every second for the life of the universe and you'd never see the same mutation happen twice.

It's trivial to produce an entirely deterministic system that would continue to exhibit evolution for more than the life of our universe. SteveBaker (talk) 15:16, 10 August 2013 (UTC)

• This notion that mutations need somehow to be random in a metaphysical sense is simply wrong. The "randomness" of mutations as described in an evolutionary sense is with regard to their effects, not their causes. The randomness of mutations has nothing to do with whether determinism is true or false, or even if the cause of the mutation is some mechanism that regularly mutates every fifth base pair or every agtcacctggcta sequence to a atacggct sequence, or unpredictably by cosmic ray, but whether the mutation is random with regard to fitness or some pre-determined goal, like developing wings from forelimbs or gill coverlets: "A widely accepted tenet of evolutionary biology is that spontaneous mutations occur randomly with regard to their fitness effect[5]" and:

  Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not "try" to supply what the organism "needs." Factors in the environment may influence the rate of mutation but are not generally thought to influence the direction of mutation. For example, exposure to harmful chemicals may increase the mutation rate, but will not cause more mutations that make the organism resistant to those chemicals. In this respect, mutations are random — whether a particular mutation happens or not is unrelated to how useful that mutation would be.[6]

  Randomness here is being used in a teleological sense, and not in regard to efficient cause. μηδείς (talk) 20:50, 10 August 2013 (UTC)
  • I've known believer scientists who've said, "Evolution is how God works." Whether you regard that as true or not depends on how you define "God". If you define "God" as "Nature" then it totally works. That doesn't prove "intelligent design", though. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:39, 10 August 2013 (UTC)