Wikipedia:Reference desk/Archives/Science/2013 June 30

= June 30 =

Plankton
I read on one fact book of mine that plankton makes up 85% of all life on earth. Now that can't be true, right? Or is it? ☯ Bonkers The Clown  \(^_^)/  Nonsensical Babble  ☯ 07:17, 30 June 2013 (UTC)


 * NPR says "Plankton make up 98 percent of the biomass of ocean life", as does this article, so maybe. Clarityfiend (talk) 07:29, 30 June 2013 (UTC)


 * Check out the article Biomass (ecology). It says most biological carbon is in land life, outweighing sea life by a factor of 50-100, not counting bacteria. There are large unknowns in the distribution of biomass though, bacteria in particular. This all assuming we are talking mass, not number of organisms (I'm guessing bacteria, again, would win a head (sic) count hands (sic) down). 88.112.41.6 (talk) 13:22, 30 June 2013 (UTC)


 * The table in Biomass_(ecology) suggests that bacteria win hands-down...but then the commentary afterwards throws doubt in all directions. I think the bottom line is that we don't know.  The error bars on all of the stated numbers are huge.  The NPR numbers quoted above only tell us what percentage of ocean biomass is plankton - so that doesn't really help.


 * But the original "fact book" fact is kinda vague. It makes a huge difference whether "making up 85% of all life" means 85% of all individuals, 85% of "wet" biomass, 85% of "dry" biomass, 85% of known species, 85% by volume...it's a very vague term and it's hard to say whether any of those possible meanings are true.  It's not impossible that if you pick the right measure - and exclude bacteria or exclude viruses or whatever - that you can make this number come out true - but it seems unlikely.


 * In all the years I've worked with the Wikipedia reference desk, I've come to believe that anything written in a "fact book" is almost guaranteed to be so vaguely specified as to be meaningless - and most likely, untrue. Those books life and die by having "amazing" facts in them...not boring ones.  Hence they cherry-pick the least likely results from the least reliable sources - and write the "facts" in a sufficiently vague manner that it's hard to either prove or discount them.  I can't count the number of times people have asked us to fact-check something they read in such books and it's turned out to be nonsense.  This one seems to follow that pattern.


 * SteveBaker (talk) 15:39, 30 June 2013 (UTC)
 * I always thought fact books were reliable sources... I assumed "all life on earth" to mean out of all living things on earth – fungi, bacteria, animals, plants, etc. ☯ Bonkers The Clown  \(^_^)/  Nonsensical Babble  ☯ 08:11, 1 July 2013 (UTC)
 * Fact books are most certainly not "reliable sources" - we've shown that here many times before. I recall one case where someone posted a couple of dozen "facts" from such a book in a question here - and we gradually found all but a couple of them to be incorrect.
 * But still, the "fact" doesn't say whether this is 85% by wet mass, by dry mass, by number of individuals, by number of species, etc. So it's just too vague.  Also, it's pretty obvious from reading our Biomass_(ecology) article that we really don't have sufficiently good numbers to answer this question definitively.  For example, it's only fairly recently that we've discovered extremophile microbes that live inside rocks 1900 feet below the sea floor under 8500 feet of ocean.  If those creatures can be found that deep into the earth's crust, then the sheer volume of space that they could possibly occupy would dwarf the thin layer of the surface of the earth that we've explored.  The potential for those things to live in such places could easily mean that they are by far the biggest number of individuals, wet and dry mass and number of species...but right now, all that we know is that we don't know. SteveBaker (talk) 14:51, 1 July 2013 (UTC)

Can box turtles crawl in high grasses
On my way home from work I noticed a turtle crawling down the center of the highway (Box Turtle, I think). I have no idea how he didn't get hit, but I decided to pull over and rescue him. I drove a little way down till I found an area that I could put him a safe distance from the road, however, the area had rather thick knee high grass and weeds, which brings me to my question: can turtles pass through this, or is their too much resistance, thus, making them effectively stuck. Honestly, I'd imagine that they would have no problem, but the question crossed my mind while finishing my drive home, I figured I'd ask since it would be a shame to rescue the turtle only to trap it another way! If for some odd reason they can't, I can always go back and retrieve him, Thanks for any help on this seemingly stupid question.Phoenixia1177 (talk) 12:15, 30 June 2013 (UTC)


 * I don't see how we can help you with sources. But my OR from having kept turtles is that while they wouldn't voluntarily climb in to tall grass (which they don't eat), they should be able to get out.  Have you felt the strength of a turtle's legs if you hold one that wants to move or get away?  Even if this is a faux pas, don't worry too much.  I was getting in the car to leave my waterfront residence on the Great Bay (New Jersey) when an obviously aquatic turtle crawled by my car door.  I knew I would pass a lake on the way home, so I put the turtle in a bucket and dropped it off on the side of a nice big freshwater lake about five miles inland.  When I got to my apartment in NYC I heard a news story about hundreds of turtles trying to lay eggs on the bayside runways at JFK airport.  I looked the animal up and found it was a northern diamondback terrapin, one of the only species of land turtle that prefers salt water. μηδείς (talk) 16:01, 30 June 2013 (UTC)
 * Ha! It's the thought that counts. More people should try to help urban turtles. Saltwater or freshwater, nobody likes being run over. InedibleHulk (talk) 01:59, 3 July 2013 (UTC)
 * Agreed. I think the OP is equating slowness with weakness, but this is not the case.  The classic example is the weed which pushes up through concrete.  StuRat (talk) 13:13, 1 July 2013 (UTC)

Thank you both for the help:-) I figured the turtle wouldn't have an issue, but just wanted to be sure; it defeats the point if not. Also, I realize that this question would be hard to source, but I figured there might be something out there. At any rate, thank you, this put my mind at ease (I'm weird, I know) :-)Phoenixia1177 (talk) 08:58, 2 July 2013 (UTC)

eggs in the afternoon
one of my friends told me that eating eggs in the afternoon isn't good for one's health. but, she couldn't elaborate on that. can anyone please tell me whether there are any health risks if i eat eggs in the afternoon?

thanks — Preceding unsigned comment added by 117.197.233.218 (talk) 14:40, 30 June 2013 (UTC)


 * We're not supposed to give medical advice, but that doesn't make any sense at all. Looie496 (talk) 15:02, 30 June 2013 (UTC)


 * A google search on "Eating eggs after noon" brings up dozens of hits from health and diet sites saying things like "Healthy Snacks to Beat an Afternoon Energy Slump: A Hard-Boiled Egg".   The trouble is that absolutely anyone can set up a diet/health web site and say just any old nonsense and people will repeat it as if it were scientific truth.  So doubtless your friend read it somewhere - and didn't read the other places that say the exact opposite.   This is very typical of these kinds of claim.


 * Bottom line is that in the absence of any scientific studies where people only ate eggs in the morning and not in the afternoon and vice-versa - with each of them eating "placebo" fake eggs at the other times - then tracked those people's health for months and years afterward, we're unlikely to know for sure. Is it likely that such a study has been done?   Hell no!  To get any kind of scientific result, they'd have to study a hundred different foods with perhaps a dozen possible time-of-day eating patterns, invent fake "placebo" foods to substitute for each one so people wouldn't know which part of the study they were in ("double-blind") and have hundreds of people in each part of the study and track them for a long time afterwards with detailed health testing.   It would be an incredibly difficult and costly exercise - and because there is little expectation of discovering major new health insights, nobody is going to fund such a thing.


 * So we're left in realms of amateur speculation and so forth. It's really, REALLY, unlikely that what your friend said is true.


 * May I suggest you ask your friend where they got this piece of information from - let us know the source and we can go an examine how that information was obtained.


 * SteveBaker (talk) 15:21, 30 June 2013 (UTC)


 * Maybe if they've been sitting out at room temperature (or worse) since the morning. Otherwise, it's silly. Deviled eggs, for example, are good at any meal. ←Baseball Bugs What's up, Doc? carrots→ 16:20, 30 June 2013 (UTC)


 * I love the idea of hundreds of research subjects spending years eating either fake eggs or not-fake eggs but not knowing which they are.


 * Eggs are traditionally a breakfast food, so eating them in the afternoon may be a social mistake but not a medical one. This tabloid source mentions research by the University of Missouri suggesting that eating eggs in the morning has health benefits. It does not suggest that other times of day are bad for eggs. Eggs do contain quite a lot of fat, so eating them when activity levels are higher, rather than lower, may be beneficial.


 * See also "Go to work on an egg", a 1950s advertising campaign that was banned from being rebroadcast in 2007 because it was felt inappropriate to imply a recommendation to eat an egg every day. --Demiurge1000 (talk) 16:35, 30 June 2013 (UTC)


 * To elaborate on wanting to eat eggs only when your activity level will be high, it's best to avoid heavy meals, including lots of eggs, right before you go to sleep, since they then tend to be packed onto the body as fat. Now "the afternoon" might be followed by quite a bit of activity for the average person, but for those whose schedule involves going to sleep soon after, then eating eggs in the afternoon could be unhealthy.  Of course, eggs aren't particularly healthy at any time.  While they do contain protein and lots of other nutrients, they also have a high level of cholesterol.  Egg whites lack the cholesterol of the yolks, but also most of the nutrition. StuRat (talk) 13:10, 1 July 2013 (UTC)


 * Eggs contain lutein and zeaxanthin, which are part of an established nutritional prevention for macular degeneration, so if work involves exposure to bright sun or comparable eyestrain they plausibly could be beneficial - I'm not aware of any published research to say that confidently, however, and the effect of cholesterol on drusen could have the opposite effect in some people. Still, depending on bioavailability parameters for these nutrients, it is at least possible that eggs could be healthier in the morning. Wnt (talk) 17:08, 1 July 2013 (UTC)

Genes and race, what do they code for?
The genes that differentiate the races of two individuals, do they code for the behavioral and temperamental differences between races? E.g. more testosterone in black males and more creativity in whites, analytical thinking in East Asians etc. Can these genetic differences also account for difference in racial IQ and crime rate? — Preceding unsigned comment added by 174.95.168.157 (talk) 18:42, 30 June 2013 (UTC)
 * No. Virtually all social aspects of "race" are just that - social aspects; genes have little or nothing to do with it. Matt Deres (talk) 20:44, 30 June 2013 (UTC)
 * Here's a bit of reading: Race and intelligence, Race and crime, Criminal black man stereotype. Matt Deres (talk) 20:46, 30 June 2013 (UTC)
 * Most of the mass murders in America seem to be committed by youngish white males. The OP/IP should ponder that point for a while before indulging in further hackneyed stereotyping. ←Baseball Bugs What's up, Doc? carrots→ 21:38, 30 June 2013 (UTC)
 * I don't think we need to assume the OP's question is bigoted any more than we should blame him for geolocating to Canada. But the question does have a false premise--there are no specific genes for specific races themselves. Rather, certain genes tend to cluster statistically in their frequencies among races in whatever sense that word is useful.  Genes for higher levels of testosterone might lead to more aggressive behavior, but there are plenty of hyperandrogenic whites and hypoandrogenic blacks.  No one would suggest a sensitive black male who likes to crossdress and works in a day care center was actually white or some other race because of that behavior. μηδείς (talk) 21:48, 30 June 2013 (UTC)
 * "Race" is culturally derived, but certain races as culturally defined often share genes at higher rates, hence may be more likely to share common characteristics like skin color, body features, vulnerability or resistance to certain diseases (e.g., sickle cell, smallpox, Race and health). Whether it extends to more psychological attributes is of course controversial. On wikipedia alone it's led to a Bleak House-esque arbitration case. See the links provided. Shadowjams (talk) 01:53, 2 July 2013 (UTC)

Something I was pondering
I was pondering about the nature of reality today and meta-stable states, and thought that given A = "system at local minimum (of energy)" and B = "system in equilibrium", B implies A (or I hope so) and so does A imply B?-- Gilderien Chat&#124;List of good deeds 21:13, 30 June 2013 (UTC)


 * No, there are numerous counterexamples. Unstable equilibrium is a common theme in natural science and in engineering.  Our article unstable equilibrium redirects to a general article on equilibrium; and you can also read about stability.  There are many instances of a system that is at equilibrium but is not at a minimum energy configuration; and there are many cases where a system is at equilibrium but is not stable with respect to any perturbations from equilibrium.   For example, an object orbiting at the L3 point of two other masses is in equilibrium, but is neither stable nor at a local minimum of gravitational potential energy.  Nimur (talk) 21:57, 30 June 2013 (UTC)
 * Would A imply B for all cases then?-- Gilderien Chat&#124;List of good deeds 23:16, 30 June 2013 (UTC)
 * You might have been considering stable equilibria (and I suspect so). Even so, the type of equilibrium remains significant. For example, a system may be in stable thermodynamic equilibrium, but it is plainly not at a local minimum of energy in the sense intended.  However, given a purely mechanical system (in which non-zero dynamic properties such as heat are taken as "not in equilibrium"), I suspect that a stable equilibrium (even under perturbations) and local energy minimum might well imply each other. In effect, A would imply B, but then in this interpretation it would also imply a temperature of 0 K.  — Quondum 23:28, 30 June 2013 (UTC)


 * There's more than one definition of equilibrium, but the simplest is that it's a critical point (mathematics) of the potential energy function. Mathematically that can be a local minimum (stable) or a maximum or saddle point (unstable), but in the real world you will never find a system in an unstable equilibrium. So I think A and B are more or less the same. This applies to thermodynamic systems too if properly interpreted (principle of minimum energy). -- BenRG 06:48, 1 July 2013 (UTC)


 * To think about this more simply - take a real world example. If you put a pingpong ball into a cup - the local gravitational potential energy minimum inside the cup means that you can shake the cup around and the ball rattles around a bit - but stays inside the cup.  That's a pretty stable equilibrium.  Put the same ball into the bowl of a spoon - and while it's still somewhat stable - a relatively small displacement is enough to knock it out.  Put the pingpong ball into a cup during an earthquake and it may bounce out.  Both cup and spoon are local energy minima.  So stability is not an absolute thing. SteveBaker (talk) 18:50, 1 July 2013 (UTC)