Wikipedia:Reference desk/Archives/Science/2011 September 9

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September 9

Atoms

How can matter have a negative charge and still be neutral ? — Preceding unsigned comment added by Cheylerae (talk • contribs) 11:54, 9 September 2011 (UTC)

An atom in it "normal" state contains an equal number of electrons (arranged in orbital shells) and protons (in its nucleus). Each electron has an equal but opposite charge to each proton, so overall the ataom has no net charge - it is neutral. In certain circumstances an atom may gain or lose one or more electrons, in which case it becomes a charged ion. Or the arrangement of electrons in a molecule may not be symmetrical - see polar molecule. Or a material as a whole may gain or lose electrons - see static electricity. Gandalf61 (talk) 12:07, 9 September 2011 (UTC)

It's perhaps useful to point out that matter appears electrically 'neutral' only far away from the elementary particles that compose these atoms, where 'far away' here means at distances much larger than the typical size of these atoms. Processes that take place within the volume occupied by a single atom, such as the scattering of charged particles in a Particle accelerator, are strongly affected by the local electrical fields. Also, some molecules, such as water, are electrically neutral in the sense that there is no overall net charge, but still exhibit a small local dipole (and therefore a residual electrical field) because the geometric configuration of this molecule is not symmetrical. Michel M Verstraete (talk) 14:52, 10 September 2011 (UTC).

Inception

is there any truth to the phenomena shown in the movie 'Inception'? — Preceding unsigned comment added by 175.110.242.217 (talk) 12:40, 9 September 2011 (UTC)

Which phenomena? If you mean going into people's dreams/minds to steal information then no, although you can mess with their minds with certain drugs to make them more talkative and likely to spill sensitive information. Googlemeister (talk) 12:58, 9 September 2011 (UTC)

See our articles in Sleep and Dreams.

• In terms of sleep: Lucid dreaming is a scientific fact.
• In terms of the brain: We do not use only 10% of our brains. We use all of it. Despite only being 2% of our total body mass, it consumes roughly 1/4th of our body's energy output.
• In terms of dying when asleep: Sudden death while asleep from cardiac arrest also exists, attributed to the Brugada syndrome. It is a disorder of the heart, rather than the brain, and has nothing to do with whether you are in another person's dreams or not, even if that was not impossible in the first place, LOL. Inception's premise requires the existence of a consciousness separate from the brain... which is barging into religion's soul idea.
• In terms of learning new things while asleep: Sleep-learning is pseudoscience, though newborns have been purported to learn while asleep (of very simple things, I might add).
• The Subconscious is not a scientifically definable term, nor testable or falsifiable. There are stages of sleep, altered states of consciousness, the unconscious mind, anesthesia awareness, coma scales, etc. but no 'layers of subsconscious'. However, Implicit memory (including procedural memory), which is a long-term memory that is not consciously retrieved, is factual (riding a bike thing). But it is probably simply automation of consciously learned behavior.
• In terms of directing future actions: Subliminal stimuli is thought to be only a result of the placebo effect, and just as effective (i.e. not at all to mildly). Imprinting is a phenomenon in developmental biology and only occurs in a very limited timespan during childhood development. Operant and Classical conditioning both rely on stimuli. Their effects on adult sentient humans is unknown/controversial, but mind control is considered a pseudoscience. It should be noted, however, that some other organisms (e.g. Hymenoepimecis argyraphaga and Toxoplasma gondii) do exhibit mind control adaptations, or more accurately, chemical reprogramming of [relatively simple] vital systems of lower lifeforms (which are, after all, little more than organic robots).
• In terms of affecting past and present thoughts: Memory and Perception are fragile and poorly understood and can be affected easily by a lot of things, including suggestions and individual preexisting bias (a person with strong feelings against the government will believe the 9/11 conspiracies; the way a question is worded can affect the answer and later recall). Memories also change continuously over time. It has resulted in the imprisonment (and probably executions) of numerous innocent people from the 'tell me where the bad man touched you on this dolly' type of questioning or people believing experiences that never actually happened (alien abductions, miracles, and government conspiracies), etc. Though the former may also be psychologically pathological.
• Nonetheless, planting a 'seed of an idea' and knowing the eventual result of the said seed is magical fortune-telling, and has about as much scientific basis as making a storm prediction from a (literal or not) butterfly effect.
• Dream invasion is also total bollocks. There is no way of measuring another person's (or even your own) Dreams objectively or reliably, much less 'delve' into it and affect it. The closest thing you can get is measuring brain activity through EEG or PET, etc. As such, all we have are hypotheses (including the connection between REM sleep, dreaming, and long-term memory).

Some of the above may be inaccurate due to my ignorance of said subjects, LOL, but in short: Yes, some of it has basis on science, but the way it's all put together is utter bullshit. The closest thing to it in real life is probably 'Truth drugs' like Googlemeister mentioned, or good ole torture, psychological or otherwise. Still a fun movie and excellent sci-fi though. :) It also doesn't preclude future discoveries, as even Carl Sagan admitted that some things in parapsychology might deserve a closer look. The science of our brains and consciousness is still very young after all.-- Obsidi♠n Soul 16:13, 9 September 2011 (UTC)

Using technology to implant a person's homunculus into another person's dreaming mind would likely be counterfactual. ~AH1 ^(discuss!) 15:10, 11 September 2011 (UTC)

about bandwidth

why we use cutoff frequencies to find out bandwidth? — Preceding unsigned comment added by 125.19.211.46 (talk) 12:56, 9 September 2011 (UTC)

Bandwidth is an arbitrary concept in some ways. It means the set of frequencies that are transmitted, but the problem is that for any real transmitter, some frequencies are only transmitted partially. In between the frequencies that are transmitted fully and the frequencies that are absent there is always a range of frequencies that are transmitted partially -- some of them attenuated only a little, others attenuated a lot. The "cutoff" is a way of picking a specific point in the partially transmitted range, so that you can get a specific number for the bandwidth. Looie496 (talk) 14:46, 9 September 2011 (UTC)

125.19, do you have some other criterion you would suggest could be used for determining bandwidth? SpinningSpark 15:12, 9 September 2011 (UTC)

This question is frequently encountered in a number of scientific fields. For instance, the bandwidth of each of the sensors in a multispectral instrument is typically defined by the Full width at half maximum. Michel M Verstraete (talk) 14:31, 10 September 2011 (UTC).

Nutritional price index shelf label

Would it help you in shopping to have as a shelf label in addition to the price per base unit of a product ($/oz. etc) a nutrition price index shelf label calculated by dividing the amount of each macro-nutrient group (fat, protein and carbohydrates) per serving by the product cost per serving?

Example: Bread costs $3.00 per loaf and there are 22 slices. Each slice costs $.1363. Each slice has:

a.. 1 grams or 9 calories total fat per $.1363 slice or 66 calories from fat per dollar of bread, or 13.84% fat per $,

b.. 10 grams or 40 calories total carbs per $.1363 slice or 293.33 calories from carbs per dollar of bread or 61.53% carbs per $,

c.. 4 grams or 16 calories total protein per $.1363 slice or 117.33 calories from protein per dollar of bread or 24.61% protein per $.

476.66 total calories per dollar. — Preceding unsigned comment added by DeeperQA (talk • contribs) 14:18, 9 September 2011 (UTC) --DeeperQA (talk) 13:05, 9 September 2011 (UTC)

Sure it could help some people a little if they were interested (honestly I doubt most shoppers would be that interested), but the store is not going to want to create that level of signage that is going to need to be changed every time the store changes their price, or the product manufacturer changes their nutrition label. Googlemeister (talk) 13:53, 9 September 2011 (UTC)

A lot of suppliers may already object to customers being able to compare unit prices but wouldn't knowing the nutrition price index difference between one loaf of bread and another help a customer make the best decision, especially if their resources were limited to food stamps? --DeeperQA (talk) 14:01, 9 September 2011 (UTC)

As I said before, yes, for those shoppers who would use it, though most shoppers would not be very interested. A lot of people shop for food based on how the food tastes and what it costs without placing the nutritional value as a high priority. Otherwise, products like Pepsi and ice cream would have far lower sales then they do. My guess is that this might be something that could work in a health food store, but I don't usually see people using food stamps there. Googlemeister (talk) 14:11, 9 September 2011 (UTC)

Perhaps you are right for another reason as well: When you compare this loaf with another loaf that costs $.62 more, has 17 less calories and 6 less slices and 7% less protein it does not seem like enough difference to worry about. --DeeperQA (talk) 14:40, 9 September 2011 (UTC)

Nutritional value also is an ambiguous term. It used to be "do I get enough calories", followed by "do I get enough protein". Nowadays, it's very hard to come short on either of those (indeed, most people have the problem of consuming too much of the first, and arguably the second). Now we would ideally have food that is low on calories, high of fiber and micro-nutrients and vitamins, and of great taste. Oh, and free ;-) --Stephan Schulz (talk) 15:12, 9 September 2011 (UTC)

Actually the calories you need to replace along with the protein and fat and carbs can be very precisely known through body measurements including respiratory metabolic analysis (not correct term) and extremely inexpensive foods (almost free) can be combined to match your needs exactly. --DeeperQA (talk) 16:32, 9 September 2011 (UTC)

What's your point? Other then professional athletes, people don't care if the diet is scientifically formulated to provide nutrients as efficiently as possible half as much as how the food tastes. Googlemeister (talk) 16:34, 9 September 2011 (UTC)

I agree but my dietician does not. ..oh the point is that some people are disabled or are on pensions and may need a way to make every cent go as far as it can. This is definitely one way to do it. --DeeperQA (talk) 16:42, 9 September 2011 (UTC)

If someone needs to make every cent go as far as they can, do you really think they can afford expensive (daily/weekly/monthl?) analysis of their precise nutrional requirements? In any case, as with SS I don't really understand your point. In most developed countries, even the poor or those who 'need to make every cent go as far as it can' don't tend to have problems getting enough calories, protein, fat etc. Cost clearly isn't preventing them and no I don't think they are overindulging because they think they need to to get enough calories, protein and fat so it seems a non-starter. Nil Einne (talk) 16:53, 9 September 2011 (UTC)

Cost of analysis is dependent on method and equipment. A library computer and a copy of a Google spreadsheet along with a food database, scale, tape measure etc. is at the bottom end. --DeeperQA (talk) 17:03, 9 September 2011 (UTC)

Such a method is unlikely to be that accurate. You seemed to be discussing a super precise way of measuring nutrional requirements which is a somewhat different thing. Of course it's clear both are fairly pointless since few are going to engage in them as few people bother with existing simpler methods like going simply by age, activity level, sex and weight or even simpler some universal RDI. Nil Einne (talk) 17:34, 9 September 2011 (UTC)

There are very precise methods and equipment like tanks to measure density to calculate body fat and metabolic respirators, etc. but these are for determining the effect of one diet versus another for say a diabetic. You are right though about people in general and nutrition seems only to be important, like exercise, for people with special interest. However, such special interest can easily be the size of a food stamp allocation, welfare check or even a pay check. Now days with computers and recession such things can be very tight indeed. Federal employees and pensioners have not had a cost of living adjustment going on 4 years while food prices keep going up. --DeeperQA (talk) 21:18, 9 September 2011 (UTC)

I'm aware of such methods. What I meant is I don't get why you brought them up in the context of poor people since they are completely irrelevent. (For those who can afford them, there's a good chance cost is much less a factor.) And I'm still confused about what you're saying. As me and several people have said several times, most poor people in developed countries don't have problems getting enough calories, fat and protein because of financial reasons so it isn't generally a barrier even in these tight financial times. As SS have said, bigger problems are getting sufficient stuff other then calories, protein and fat. I would add your idea breaks down even more when we consider if someone is really going to go thorough all the trouble you've mentioned to work out what their intake needs to be, there's no reason they can't just add the prices to their info and work out for themselves what's most cost effective. It's not going to take that much more time. Therefore your idea of including the cost per whatever nutrition is even more pointless. I would note even for the tiny number of poor people who do have an interest in doing such a thing, the number who are interested in your idea of going completely by cost and ignoring taste, personal preference, variety etc is likely to be even smaller. (This doesn't mean cost isn't a factor.) I'm well aware of the lack of a COLA rise since I pointed out the nonsense you were claiming here Wikipedia:Reference desk/Archives/Humanities/2011 July 25#austerity programs about a 30% rise of food and power. What I don't get is the relevence of the lack of a cost of living allowance since regardless of the harmful effects, I don't see any evidence a large number of people affected are not still getting more then enough calories, protein and fat or are interested in buying food by the cost effectiveness of getting sufficient calories, protein and fat content. Nil Einne (talk) 13:31, 10 September 2011 (UTC)

I think that fat, carbohydrates, and protein in recommended proportions adding up to recommended caloric intake calculated to indicate per serving cost is too complicated to be accepted by most shoppers. It sounds like something that might be calculated in a veterinary realm, where raising animals might be designed to result in optimal health while keeping costs under control. Human beings probably would balk at any inadvertent implied reduction of their human status to mere processors of nutritional intake for the furtherance of life—albeit at maximum efficiency and while keeping maintenance costs low too. Bus stop (talk) 15:11, 9 September 2011 (UTC)

To be honest it did get boring real quick but when I realized how much better I felt and how much weight I had lost I started inserting those meals ounce again into my diet for those benefits mixed with foods I would die for. Unfortunately it does not work that way. You have to be superhuman mentally first before you can handle a subhuman diet. --DeeperQA (talk) 16:39, 9 September 2011 (UTC)

I don't think it would help for these reasons:

1) People have a limited time to shop, and comparing that level of details just takes too long. Shop owners also wouldn't want people clogging the aisles trying to digest all that info.

2) The "price per unit" labels are hard enough to read now, due to tiny writing and often being too low or high, so out of ideal visual range. If you add all that info, that would make them even harder to read. (A pet peeeve of mine is that they use different "units" to compare different items. Some may be "per pound", some "per liter" and some "per item". Thus, you need a calculator, conversion factors, a list of densities, and a scale, to figure out which is the better deal.) So, I think we should fix the current shelf labels before we even consider adding more info.

3) Different people have different nutritional needs, and "things to avoid" is at least as important as "things to get". Indeed, few of us suffer from major nutritional deficiencies, and almost all of us get too much of some "nutrients", like sugar, sodium, saturated fats, trans fats, and cholesterol. StuRat (talk) 17:04, 9 September 2011 (UTC)

Having just returned from Tesco's, I'm prompted to endorse StuRat's points. It gets even more complex when, for poverty reasons, you're also considering items that have been variously reduced for reaching their sell-by dates (also, do you go for the first reduction to about 51% of full price, or go back later hoping the item is still there and has now been reduced again to about 26%?).

What amuses me is that often very similar items from different brands have different comparison calculations (in, as said, too-tiny print), with some given as XXp per 100g and some (usually the more expensive anyway) as £X.XX per kg - the conversion is trivial, but unnecessarily adds a further minor cognitive barrier. {The poster formerly known as 87.81.230.195} 90.197.66.202 (talk) 18:54, 9 September 2011 (UTC)

Yes, this problem is so widespread, it's difficult to think it's solely due to incompetence. I have to suspect that they want to give the impression of helping you to find bargains, without actually doing so. StuRat (talk) 04:56, 10 September 2011 (UTC)

British supermarkets normally have standardised price comparisons (as pence per 100g or pence per 100ml), though usually in very small print on the shelf-edge label. Dbfirs 16:17, 10 September 2011 (UTC)

Don't they ever sell items at a price per item, versus volume or weight, like fruit or other produce ? StuRat (talk) 17:33, 10 September 2011 (UTC)

Yes, they (I speak mainly of my nearest Tesco and Sainsbury's, which are within walking distance, as is a Lidl though I tend not to buy foodstuffs regularly from them) do that too. Usually it's for items that are logically sold by number, but it's annoying when they do it for items that, in different packaging, are also sold by weight or volume, such as onions that are sold loose by the pound and kilo, but also in packs of three that have no indicated weight, particularly as within the last couple of years they've (both) removed the set of scales that used to be provided in the vegetables & fruit area for customers' use. {The poster formerly known as 87.81.230.195} 90.193.78.51 (talk) 19:32, 10 September 2011 (UTC)

They really don't want you to do price comparisons, do they ? Here in the US, some loose produce items are sold per count, and some per pound. Then they also sometimes stuff some in a bag that's supposedly of a certain weight, but, of course, the actual weight may vary by quite a bit. If they stuffed it in the bag before you arrived, it's priced as if it were the weight written on the bag. On the other hand, if you ask for a pound of some food at the deli, they will give you something near a pound, but charge you for the actual quantity. (I'm reminded of a Jack Benny skit where the deli owner took a bite out of Jack's cheese so it would weigh exactly a pound, so Jack ordered a pound of raw liver to see if he would bite that, whereupon he had his dog take a bite.) StuRat (talk) 02:20, 11 September 2011 (UTC)

vision of the human being

I wonder why the human specie does not see in 3-D. I mean, of course it sees the distance between an object with the individual, but if object A is between the individual and object B, only object A will be seen. let me word it mathematically: if x1!=x2 and y1=y2 on a plane,both of the object will be seen. but if x1=x2, and y1=y2 but z1!=z2 the object will be covered. so why is our brain works on 2-D and not on a 3-D? Exx8 (talk) —Preceding undated comment added 13:41, 9 September 2011 (UTC).

I don't get it. Are you asking why if there is a house in front of us, why can't we see the car on the other side? Googlemeister (talk) 13:50, 9 September 2011 (UTC)

We don't have X-ray vision. PrimeHunter (talk) 13:51, 9 September 2011 (UTC)

A more fruitful approach would be to try and imagine the biological capability that would result in what you are talking about (eyes on stalks? compound eyes? ability to perceive x-rays?) and then try and figure out why that didn't end up evolving. Even that is a backwards approach to thinking about human evolution. Our vision is a result of our evolutionary development — we have reasonably good vision for mammals, the binocular vision of most predators, and better visual bandwidth (in terms of frequencies distinguished) than many mammals (e.g. dogs). --Mr.98 (talk) 15:04, 9 September 2011 (UTC)

Actually, this question is more intelligent than it first sounds. But it has nothing to do with the workings of the human brain. Rather, the reason we cannot see 3D objects which are blocking each other is that we (the observers) are embedded in the same 3D space as the objects. We do not have the same trouble with 2D objects because we are able to view the scene "from the side" as it were, by taking ourselves out of the 2D space the objects are embedded in by moving out in the third dimension and viewing from a distance - like looking down on a 2D ants' nest. One of the 2D ants, however, will have some objects blocked from view because the ant is embedded in the same 2D space as the objects and is unable to get a complete picture of the entire plane no matter where it stands. On the other hand, if we were able to move in 4D space we would be able to get a view of the 3D world where we could see every object because we would no longer be embedded in 3D space. SpinningSpark 15:07, 9 September 2011 (UTC)

That reminds me of Flatland; Well worth a read btw. Stanstaple (talk) 17:59, 9 September 2011 (UTC)

Seconded, but I remember having a long argument about the work some time back. I maintain that the sexist and patriarchal society the Flatlanders are portrayed as having is a deliberate and funny satire by the author of his contemporary Victorian society, but another reader insisted that it was actually intended as an endorsement of those values. {The poster formerly known as 87.81.230.195} 90.197.66.202 (talk) 19:14, 9 September 2011 (UTC)

Actually, we do exist in 4 dimensions, with the 4th dimension being time, and this does allow us to form a good 3D picture of the world. In the case of the car parked behind the house, we walk around the house, observe the car, and remember it, and this becomes part of our 3D visualization of the property, even after we return to the front of the house. Of course, this info does eventually become out-of-date, say if somebody drives the car away, so we need to check out our environment from time to time to update our mental model.

And ants, BTW, are as 3-dimensional as us, just on a smaller scale. StuRat (talk) 17:10, 9 September 2011 (UTC)

I was, of course, specifying 2D ants in a 2D world as a thought experiment; I certainly did not intend to imply that real ants were 2D (and a real ants' nest is anything but 2D). Likewise, talk of a 4D world is a thought experiment with four spatial dimensions. Consideration of time as a fourth (temporal) dimension is valid but a bit of a red herring as far as this question is concerned. SpinningSpark 18:14, 9 September 2011 (UTC)

Observers see one less dimension than the one they're in. There is a term for this...but it escapes me atm. See this page from How the Mind Works.Smallman12q (talk) 18:03, 9 September 2011 (UTC)

I don't know the name of the principle either, but it is based on the geometric fact that the boundary of any geometric region has one less dimension than its interior. Information from the 3D physical world gets into our eyes through a 2D surface; a filter which strains the full flavoured 3D brew into an insipid 2D version. SpinningSpark 18:32, 9 September 2011 (UTC)

That may be part of the Fundamental theorem of linear optimization which states: 'The boundary of any geometrical region has one less dimension than its interior'.Smallman12q (talk) 13:03, 12 September 2011 (UTC)

I suppose we do see in 3D to some extent in the sense the OP meant via amodal perception. Sean.hoyland - talk 18:43, 9 September 2011 (UTC)

Well I do see in 3D in a sense, I feel structures like buildings inside myself. Bits I don't know about have a vagueness quality. Other bits have strength or hardness or amount of light or texture. However I don't have a colour associated with things when I feel them in this manner, for that I visualize them as 2D images like you say. Also the extent is enclosed rather than extending off to the horizon. Dmcq (talk) 19:02, 9 September 2011 (UTC)

Perhaps related to what the OP was thinking of, we do have somewhat poorer depth perception in the vertical plane than in the horizontal, because having (only) two eyes separated horizontally allows us to use Stereopsis only in the horizontal. If we had three eyes arranged in, say, an equilateral triangle - thus ∴ - we would have improved depth perception and also be able to see a little 'over the top' of obstructions without moving. Having three (or more) eyes on stalks would be a very interesting experience (and very useful in crowds at sporting events and concerts!). {The poster formerly known as 87.81.230.195} 90.197.66.202 (talk) 19:07, 9 September 2011 (UTC)

If the background object is larger than the foreground object, then it can be seen. If the size difference is large enough, and the foreground object is close enough, the entire background object can be seen. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:53, 10 September 2011 (UTC)

Well, as i explained to you tomorrow (working up the page here) the visual cortex is designed to that what start out as bright and dark responses from individual receptors in the eye get organized into edges, where there is a sharp discontinuity in brightness (doesn't have to be large, but does have to be NOT gradual); and these are organized to give corners, and t-junctions where one line crosses another. and when you think about it, that's about all you need to be able to figure out which object is in front of another. if you look around nature, you will see that there are very few real cross-intersections where 4 lines join, the vast majority are either corners or the t junction where the edge of one object cuts off the edge of another. the other stuff like your eye's depth of focus and the stereoscopic vision is useful for depth perception, but for parsing out objects, you can certainly do it with one eye closed. of course, color vision helps too. Gzuckier (talk) 05:50, 12 September 2011 (UTC)

What is the biggest locomotive organism capable of photosynthesis?

Elysia pusilla, a sacoglossan feeding on green algae.-- Obsidi♠n Soul 18:35, 9 September 2011 (UTC)

And are there even such creatures? multi-cellular ones?--Irrational number (talk) 18:01, 9 September 2011 (UTC)

Are you looking for Cyanobacteria?Smallman12q (talk) 18:03, 9 September 2011 (UTC)

well, they're mono-cellular... ?--Irrational number (talk) 18:06, 9 September 2011 (UTC)

I'm betting on a floating island. Dauto (talk) 18:10, 9 September 2011 (UTC)

Not as big as a floating island, but as our article Photosynthesis#Symbiosis and the origin of chloroplasts explains, there are a few species of marine molluscs that are capable of photosynthesis, using chloroplasts that they get from ingested algae. Looie496 (talk) 18:17, 9 September 2011 (UTC)

Indeed. One example is Elysia chlorotica, which can reach 6 cm in length. --Stephan Schulz (talk) 18:25, 9 September 2011 (UTC)

(e/c and Stephen Schulz and Looie496 beat me to it, LOL) Seeing that you didn't specify 'plants': sacoglossans, a clade of sea slugs. Specifically the eastern emerald elysia (Elysia chlorotica). They are famous for kleptoplasty and are the only known higher animals capable of functional photosynthesis. Note that this is not normal symbiosis, as the animals only preserve the chloroplasts of their prey (algae) and not the living algae itself. It mimics the actual integration of chloroplasts by ancestral bacteria (chloroplasts and other plastids are believed to have once been separate organisms on their own, engulfed but symbiotically kept alive by their hosts), comparable to how mitochondria (which have their own DNA) were integrated into eukaryotes earlier and is now usually propagated by the egg cells. Also see Endosymbiotic theory and Horizontal gene transfer, another of the weird mechanics of evolution.-- Obsidi♠n Soul 18:35, 9 September 2011 (UTC)

A triffid (fictional). Itsmejudith (talk) 19:14, 9 September 2011 (UTC)

Some might argue for a clonal mangrove swamp. One current webcomic even features a couple of sentient ones, but I'm prepared to admit that it sometimes teeters on the edge of science fiction (ahem!). {The poster formerly known as 87.81.230.195} 90.197.66.202 (talk) 19:38, 9 September 2011 (UTC)

I would argue that a mangrove swamp is not locomotive. Googlemeister (talk) 20:23, 9 September 2011 (UTC)

I was under the impression that a mangrove grove could shift position relatively quickly compared to groves of other trees or similar plants by selective growth and die-back of its rather leg-like roots, and being a clone could be considered as a single organism. I'm not seeing references to this in the article, so maybe I'm misremembering the plant concerned, or am just delusional. {The poster formery known as 87.81.230.195} 90.197.66.202 (talk) 12:22, 10 September 2011 (UTC)

Maybe you meant the quaking aspen Populus tremuloides? They form clonal groves (the most famous being Pando). Mangroves, on the other hand, generally do not propagate vegetatively without human intervention despite their apparent 'rootiness', heh. The substrate they are on is usually anoxic (hence the roots, which function like snorkels) or otherwise hostile for that kind of propagation (even their normal sexual propagation methods are highly specialized). Banyans also have those massive tangled aerial roots and can cover quite large areas, but they are single organisms and are also not very inclined to reproduce vegetatively.-- Obsidi♠n Soul 13:03, 10 September 2011 (UTC)