Wikipedia:Reference desk/Archives/Science/2017 June 24

= June 24 =

What Herbivores and Omnivores could realistically live and even thrive in an arctic land where snow covered the ground most of the year ?
What Herbivores and Omnivores could realisticly live and even thrive in an arctic land where snow covered the ground most of the year, some 3/4 of the year ??

I know Reindeer/Caribou and Bison, just to give two examples, can manage just fine in harsh winter conditions. Bison can reach grass underneath by digging through the snow. But in a land where the summer season barely exists and the grass barely gets time to grow in between winters, I imagine it would be very much different.

So what Herbivores and Omnivores (of any size) could live in such a place and thrive, and how would they eat? Many examples would be appreciated, the more the merrier

Krikkert7 (talk) 09:12, 24 June 2017 (UTC)


 * We have an article on psychrophiles, not all of which are prokaryotes. --Cookatoo.ergo.ZooM (talk) 11:00, 24 June 2017 (UTC)


 * One option is to get food elsewhere (ocean fish, for example), then go to the polar region for safety from predators. This is what the documentary March of the Penguins described.  Seals also try this approach in the Arctic, but are less successful at avoiding predators, as polar bears often sniff them out in their hiding spots under the snow. StuRat (talk) 20:06, 24 June 2017 (UTC)


 * This isn't a full answer, but it's worth reading insolation. The light reaching the poles is actually theoretically higher than elsewhere during a portion of the year.  Plants have to convert that light into some energy resource at the moment it falls.  So in theory, if a plant can find a way to grow that exposes it to the light, and your herbivore can properly harvest and digest the plant, and if it can hibernate or go away for half the year with low energy cost, it should be pretty much happy.  And so for example, whales are seen in the deep Arctic doing very well on the phytoplankton that grows abundantly in the summer. Wnt (talk) 17:00, 25 June 2017 (UTC)

User: Wnt: Hm, that's actually quite interesting.

User: StuRat: I believe I've seen the March of the Penguins. Interesting documentary as I can recall it. But Seals are Carnivores, and unless I am mistaken so are Emperor Penguins - you said yourself; to hunt fish. If they can, the females eat so much fish and crustaceans they nearly burst, then they return to their baby penguins to share that fish with them in the form of delicious puke. So they survive by eating meat. They're neiher herbivores nor omnivores, as far as I can tell.

But let me ask a different question; it wouldn't necessarily take much summer for things to grow, would it ??? Grass, at least, grows very fast, and can be very hardy. If things can just grow for a short period of time, during a short summer, then animals such as the bison and reindeer and probably many more than I am aware of can reach it through the snow. In the hardiest conditions, I also know that Snow hares can feed mainly on twigs, rather than greenery. Krikkert7 (talk) 18:20, 25 June 2017 (UTC)
 * Bison are more a non-Arctic animal. And there is plenty of plant life on the tundra during our short summer season, see Category:Arctic flora. Even though we don't have the bison the caribou can get at the plants under the snow in winter and lemmings live under the snow. Of the herbivores muskox are probably the largest and lemmings amongst the smallest. For more take a look at List of mammals of Nunavut, it includes carnivores and animals like the moose that are only found in the deep south, and see Category:Arctic land animals., you have it partially right. The bears do hunt seals but seals don't hide under the snow. Seals keep breathing holes holes open in the sea ice, as much as 3 m thick, all winter long. The hole may have a thin cover of ice or snow over it. The bear finds the hole and lies in wait for the seal. Alternatively, the bear may observe a seal on the ice. It is able to creep up and get the seal. Some people will say the bear will cover its nose with its paws to hide the black. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 01:54, 26 June 2017 (UTC)


 * The cold is more of a problem for plants than the lack of light. That is, the plants would need to be able to resist freezing to death in winter.  In more temperate climates they can retreat to underground roots, bulbs, and tubers in winter, but once you get to an area with permafrost, those would freeze, too.  Specifically, water forms ice crystals which bursts their cell walls.  Some type of anti-freeze would be needed for them to survive.  Then there's a problem with a plant colony living on a glacier, which would likely mean it would eventually die when it calves off into the ocean.  So, plants would need to find an outcrop of rock, both to remain anchored and to get the minerals they need.  Then, as you mentioned, plenty of herbivore mammals could exist in such a climate, if they could find plants to eat, so there would be lots of animals eating any plants that do manage to survive.  So, it's tough going for a polar plant. StuRat (talk) 01:47, 26 June 2017 (UTC)
 * I know that viable plants have been found under glaciers but I don't think there are many growing on them. Here's a short article that explains how they survive the winter. Mosses and lichens do grow on rocks but there are plenty of plants as well. This says there are about 1,700 species in the Arctic but this says 140. Note that lack of water is a problem. I also found Arctic vegetation which I hadn't seen before. As this points out some plants can be used by humans and other animals such as bears and Jstor has something on that as well. Here's an interesting bit on edible plants just don't eat the mushrooms. By the way there is one group of omnivores that lives and thrives in the Arctic, Category:Indigenous peoples in the Arctic. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 05:11, 26 June 2017 (UTC)


 * For comparison, there are something like 400,000 total species of plants worldwide: . So, whether it's 1700 or only 140 that manage to survive in polar regions, either way it's a tiny portion.  There are also problems related to reproduction, since pollinators like bees, ants, and hummingbirds don't survive there.  So, probably best to use asexual reproduction there.  Then there's the issue of how to distribute seeds.  Water-borne plants would have an advantage here, at least when the water isn't frozen as ice.  There may not be any birds to eat berries and poop seeds out far away, so they would need to rely on mammals for that (although there are some polar birds).  Hitching a ride on passing animals could work, as in burrs, but there may not be enough animals to make that method viable. StuRat (talk) 05:28, 26 June 2017 (UTC)


 * Would not the brightness at higher latitudes and elevations be affected by snow and ice? In the Arctic the glare can be painful. 81.27.92.74 (talk) 06:34, 26 June 2017 (UTC)


 * The discussion is at Reference desk/Archives/Miscellaneous/2017 February 3. 81.27.92.74 (talk) 06:34, 26 June 2017 (UTC)


 * Please don't make stuff up. While I haven't seen any there may be some ants of the Formica genus. There are certainty bees in the Arctic, Bombus polaris and Bombus hyperboreus which play a small role in pollination. Flies are the major plant pollinators. As for birds only the snowy owl and ravens overwinter but Category:Arctic birds shows that plenty send several months here and some, Arctic tern, common raven and Canada goose, eat berries. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 06:57, 27 June 2017 (UTC)


 * It's interesting that 2 species of bees do manage to survive in the polar regions, but that's still a tiny proportion of the 20k species our bee article says exist, so they aren't common pollinators in polar regions, as they are elsewhere (unless there's far more bees in those two species than in most of the others). StuRat (talk) 23:16, 27 June 2017 (UTC)

Is it a goat or a cow?
When I first saw this short clip, I thought the climbing animal was a baby goat. Then someone suggested it was a baby calf and looking around I'm not sure now. So is it a goat or a cow? [//imgur.com/kfgBFtJ] Nil Einne (talk) 13:59, 24 June 2017 (UTC)


 * Goat - no doubt at all. That short tail sticking up in the air is the clue - cows all have long dangling tails. Wymspen (talk) 14:26, 24 June 2017 (UTC)


 * Off topic: Here's a fun one. Wnt (talk) 17:06, 25 June 2017 (UTC)

Ethidium bromide (done)
Can anybody here explain where the name Ethidium and the former name Homidium come from? I didn't manage to find a proper etymology for neither of the two.

PS: Since I'm not a native speaker and interested in linguistics (as my question probably already implies): Is the double negative in my last sentence incorrect? If so, how could I avoid it [changing as little as possible]? Hoping for your support, best--Curc (talk) 17:44, 24 June 2017 (UTC)
 * It would have been more correct to say "didn't ... find ... either", as in "one or the other", as opposed to "neither" (not one or the other). No information as to your first question.   General Ization   Talk   17:50, 24 June 2017 (UTC)
 * You could also say "I found proper etymology for neither of the two" but it sounds more formal, and is maybe less likely to be understood by non-native speakers.  D b f i r s   19:37, 24 June 2017 (UTC)
 * Thank you very much for at least helping me along with the English! Now, to round off this issue: Would there maybe have been a more natural / idiomatic formulation (do you use "formulation"?) you would have used? Best, --Curc (talk) 23:39, 24 June 2017 (UTC) ;-)
 * I probably would have said: "I couldn't find a proper etymology for either one."  General Ization  Talk   23:57, 24 June 2017 (UTC)
 * Thanks once more! Now we only need somebody who can tell us about the etymology itself... ;-)--Curc (talk) 00:21, 25 June 2017 (UTC)
 * I could guess it comes from a simplification of the systematic name 3,8-Diamino-5-ethyl-6-phenylphenanthridinium bromide. Graeme Bartlett (talk) 00:56, 25 June 2017 (UTC)


 * I looked homidium up in PubMed, sorted by oldest results (they go back to 1954) and took the first paper (1957) that I could access text on (none had abstracts). Inadvertently, I'd pulled up ethidium because I didn't qualify the search.  Anyway, the paper provides a useful clue:
 * "Certain phenanthridinium compounds, originally synthesized by Morgan, Walls, Browning, Gulbranson & Robb (1938), possess trypanocidal properties (Browning, Morgan, Robb & Walls, 1938) and have been used with success against Trypanosoma congolense and T. vivax infections in cattle. Walls (1945) demonstrated that high trypanocidal activity in the phenanthridine series is a property of quaternary salts containing a primary amino group in the 7- and a phenyl group in the 9-position; the activity is much increased by the presence of a second amino group, thus 2:7-diamino-9-phenyl-10-methyl phenanthridinium bromide (dimidium bromide) and the 10-ethyl analogue (ethidium bromide) are particularly effective (Watkins & Woolfe, 1952; Woolfe 1952)."
 * So clearly the eth comes from the 10-ethyl component in that reference -- note that is the N+ in our current article diagram and 5-ethyl in the IUPAC name. The one sure thing about numbering these things is that there's always more than one way it has been done in the literature. ;) Wnt (talk) 01:35, 25 June 2017 (UTC)
 * The Walls 1945 reference is putatively available here; I at least see it cites B. PP. 511,353 and 520,273 (I take those to be British patents). I didn't find these on Espacenet but I did find a US patent that mentions them  but without etymology, or indeed the word "ethidium" that I noticed. Wnt (talk) 01:52, 25 June 2017 (UTC)
 * Thanks alot for your research! While you were at it, have you found anything about the Homidium by any chance?--Curc (talk) 17:45, 26 June 2017 (UTC)
 * I'd forgotten about it, but it only takes a moment to go to PubMed, which is a free resource for public use, and type "homidium", and then (this time) click Advanced Search and specify title/abstract for the word, to exclude all the MeSH synonym hits. That gives a list of 61 papers instead of 10,000; choosing "last" I get  which uses the term but doesn't explain why, from 1960.  I also noticed  which potentially might be useful.  Well, acting on a hunch, I went to plain Google with homidium "trade name", expecting it was the trade name -- surprising thing is, according to this  ethidium is the trade name.  This is plausible - I've seen cases where drug companies make a well known name proprietary and then the capitalist acolytes dutifully scurry to use some little known generic substitute name.  In this instance that appears to have been singularly unsuccessful!  But I'm kind of stumped to think of where to trace the trail further back - there's a source you can chase from that 1960 paper, but I bet it will turn out to just use "ethidium", because it should be a paper indexed by NCBI.  My guess would be that "homo" is used to indicate that an extra -CH2- is added somewhere in a compound, like homocysteine and homoserine. So "ethidium" might have been coined to indicate the CH3-CH2- was substituted for CH3, while "homidium" was coined to suggest -CH2- was added to CH3-. Wnt (talk) 18:55, 26 June 2017 (UTC)
 * Sorry, but I'm a little confused now: In your hypothesis, the CH3-CH2 compound was there in the first place, then substituted to only CH3 (ethidium) and finally added again to CH3-CH2 (homidium), or did I misunderstand you here?--Curc (talk) 19:15, 26 June 2017 (UTC)
 * Somewhere you got confused. Methyl is CH3-.  Ethyl is CH3CH2-  And "homo" means adding -CH2-.  So "ethyl" anything could be "homomethyl", but I do sincerely hope that abomination has never made it into print. ;)  (Well, I see on a search it has, but mostly as a mis-scan of homomenthyl salicylate) Wnt (talk) 19:19, 26 June 2017 (UTC)
 * Well, now you've really lost me! You write: "So "ethidium" might have been coined to indicate the CH3-CH2- was substituted for CH3, while "homidium" was coined to suggest -CH2- was added to CH3." — Now, this sounds to me as if you wanted to say the formula had been originally with the CH3CH2, which was then "substituted for CH3" and finally re-substituted to the original CH3CH2 ("to suggest -CH2- was added to CH3") by a different company using the new (generic) name homidium. Where is my fallacy?--Curc (talk) 19:31, 26 June 2017 (UTC)
 * I'm not sure what you're not understanding. (Just in case there is a language issue, I should point out that A was substituted with B matches Romance languages where you lose A and get B, but A was substituted for B is more common in English and means you lose B and get A)  (Since posting this I already ran into another deviation from that idea in this otherwise intriguing paper - "Once we identified the molecular mechanism underlying the trimethoprim + AZT interaction, we substituted trimethoprim for another FDA-approved small molecule. This newly designed combination, floxuridine + AZT..."; this happens pretty often nowadays, but that's not the standard usage.)  The names are not systematic - they added a second amino group, so they called it dimidium (di- meaning two).  That compound happened to have a 10-methyl.  Then they changed 10-methyl (-CH3) to 10-ethyl (-CH2-CH3) and they called that both ethidium and homidium.  Because replacing methyl by ethyl or adding -CH2- to methyl is the same thing. Wnt (talk) 15:49, 27 June 2017 (UTC)
 * Thank you very much for once more clarifying the matter! Best--Curc (talk) 21:15, 28 June 2017 (UTC)

Wetness meter
I've purchased a hydrometer they actually call wetness meter, for my garden at Amazon. It has a scale and a hand. It works well. When I put it in the ground the hand promptly moves to the right if the ground is wet and ends up in a green zone. Where's the battery? Is it a Perpetuum mobile? Simple examination shows there is no compartment for the battery and it is not mentioned in the instruction. "Made in China," of course. How does it work? Thanks, - --AboutFace 22 (talk) 22:35, 24 June 2017 (UTC)
 * See galvanic cell. Basically the water in the soil and the two electrodes form a battery, and the meter measures the output of the battery, which is high when sufficient water is present and low or absent when it is not. The key (and non-obvious) aspect is that the electrodes are made of two different kinds of metal.  General Ization   Talk   23:13, 24 June 2017 (UTC)


 * Also remember not to leave in the ground permanently as the anode will dissolve away and it will stop working. Aspro (talk) 00:18, 25 June 2017 (UTC)

Clear. Thank you --AboutFace 22 (talk) 12:53, 25 June 2017 (UTC)

StuRat (talk) 03:20, 25 June 2017 (UTC)