The latest issue of Science contains two papers (references below) worth reading. Sadly, both are behind paywalls, but judicious inquiry might yield a pdf). One, a short perspective by Simon Fisher and Matt Ridley, emphasizes that a lot of genetic changes supposedly responsible for major features human evolution—like the highly-touted FOXP2 gene, whose evolution was supposedly the cause of human speech,since mutations in the gene degrade human speech and that gene evolved quickly on the hominin branch of the ape lineage—might have evolved quickly only after cultural innovations or changes in other genes allowed the supposedly “responsible” genes to evolve in concert with that other change.
An example of culture-driven genetic evolution is the rapid evolution of lactose tolerance genes in human populations, which I recount in WEIT. In the descendants of human “pastoral” populations (that is, those groups who kept sheep, goats, or cows for milk), we observed the rapid evolution of lactose tolerance within the last 10,000 years. Most humans are lactose tolerant as infants: we have to be, because we drink milk. But as infants age and get weaned, the genes allowing them to break down the lactose milk sugars got turned off, for milk-drinking wasn’t a feature of early human populations. As humans domesticated animals for milk, a cultural change, there arose powerful selection pressures to not turn off those genes so that we could derive continued nutrition from those milk sugars. (The selection pressure is estimated at an astounding 10%, meaning that those individuals who could digest milk left 10% more offspring than those whose tolerance genes remained turned off.) This cultural change of keeping milk animals, then, caused a rapid genetic evolution of permanent “on” genes in several populations. This is known as “gene-culture coevolution.”
Fisher and Ridley make the point that the rapid evolution of FOXP2 could mean not that evolution at that gene enabled humans to use language, but simply refined our abilities to use sophisticated vocal communication after it had already developed via earlier genetic and cultural evolution. Or, FOXP2 could have nothing to do with language at all, but simply reflect some other form of selection.
Their argument makes sense, and I like it because I also raised doubts about the FOXP2 story in WEIT. Geneticists and evolutionists are all too eager, when they find a gene that has evolved rapidly in the human lineage, to speculate that this is the gene responsible for some innovation “that makes us human.” Fisher and Ridley simply note that the rapid evolution could be a consequence rather than a cause of something that had already evolved—be it culturally or genetically.
*****
The second story is amazing, demonstrating the old evolutionary bromide in the title. When an animal becomes resistant to something that humans use to poison it, it usually evolves to detect that poison and avoid it, or become physiologically resistant to it (as bacteria become resistant to antibiotics or mosquitoes to DDT). But in the case of the German cockroach (Blattella germanica), it’s done something more clever: it’s somehow re-jiggered its taste system so that the attractant that humans used to draw the insect to poison bait—the sugar glucose—now tastes bitter to the roach, and they avoid it.
Before the mid-1980s, roach control experts would spray poisons on everything to control roaches. That didn’t go down very well with people, and so the companies switched to baits, which included not only a poison, but something to attract the roaches to the deadly baits: the sugars D-glucose and D-fructose, which roaches love. (Sucrose, our table sugar, is a dimeric molecule that links fructose to glucose.) But within a few years, cockroaches began appearing that avoided the baits, and did so not because they were averse to the poison, but because they were averse to the attractant, glucose. This new trait turned out to be heritable, that is, it had a genetic basis.
Ayako Wade-Katsumata and coauthors hypothesized that the aversion to glucose was a result of evolution in the way the taste buds and brain detected and perceived the sugar.
To figure this out, they wired up nerve cells (neurons) in the cockroaches’ taste receptors (“taste sensilli”), which reside in hairs around the mouth. The figure below, from the paper, shows those hairs and the kind of single hair whose nerve cells (those cells that detect and respond to stimulants) could be wired up to see if the nerve cells fire when exposed to different molecules. (It’s amazing what neurophysiologists can do these days). There are several types of taste receptors in the hairs, but the authors concentrated on two: those that, when they fire, send a signal to the sweet detector in the brain, and those cells whose firing sends signals to the bitter detector in the brain. In normal, unselected roaches, only the first cells fire when the beast tastes glucose, stimulating it to feed. When the bitter receptors cause the bitter neurons to fire, the roaches avoid what they’ve tasted.
- (Caption from Fig. 1 of paper). Side view of the right paraglossa of a WT [“wild type”, i.e. not glucose-averse] male cockroach (left, maxillary and labial palps were removed), and a taste sensillum used in electrophysiological recordings (right).
What the authors found is that in cockroaches that had evolved to avoid baits, glucose stimulated the firing not only of glucose receptors, but also the bitter receptors. (The positive response of the sweet receptors to glucose was also lower in bait-averse cockroaches than in normal, wild-type cockroaches.) In other words, what once attracted the roaches to baits now repelled them.
The authors don’t yet know the genetic and neurological details of how this happened. As they note, it could be caused by structural changes in the “bitter’ receptor molecules so that they now detect glucose but send signals to the bitter neurons, causing aversion. Alternatively, there could have been mutations that put glucose-detectors on the bitter-tasting neurons, so that they’d fire in response to glucose, but send “ecch” signals to the brain.
The lesson from this, besides being the usual cautions that evolution is unpredictable, and that natural selection can often favor striking and unexpected responses, is that taste, like every other sense, reflects a combination of external stimuli and neuronal wiring that tells the brain how the brain interprets those stimuli. Something being “tasty” or “repugnant” is not an inherent quality of a food but of the combination of food and how it stimulates the taste receptors and brain. Receptors can evolve in a way that makes something that once tasted great now taste horrible, or vice versa. (That goes for odors, too.) I’ve always said that rotting meat probably tastes as good to a vulture as an ice-cream sundae does to us. (And if you don’t like ice-cream sundaes, you’re reading the wrong site!)
h/t: Linda Grilli
________________
References:
Wada-Katsumata, A., J. Silverman, and C. Schal. 2013. Changes in taste support the emergence of an adaptive behavior in cockroaches. Science 340:972-975.
Fisher, S. E and M. Ridley. 2013. Culture, genes, and the human revolution. Science 340:929-930.
Wow…I wonder if ants do this too. It is a pity (sort of) that certain clusters of humans don’t evolve something to make junk food taste bad. 🙂
In a way that has already happened. Our brains have evolved a way of learning aversions. I was born with a sweet tooth but now eat no sugar at all because the thought of it induces anxiety that it will exacerbate my diabetes.
I call bullshit, we grow out (literally) of having a taste for sugar because we no longer need very high energy food for development as we age.
Look, it’s rude to “call bullshit” on another reader. Don’t do that again.
That’s OK, it wasn’t bovine faeces anyway. I didn’t ‘grow out of’ my taste for sugar, it just stopped one day at my doctors office.
I didn’t lose my craving, that’s still there, it just gets overridden.
You’d be amazed at just how much sugar American adults consume.
In the 1700s, before the start of the sugar trade, average consumption was on the order of a tablespoon a day, or a teaspoon per meal. That includes sugar in all forms, from jams to syrups to honey to sweet baked goods to whatever. That’s roughly ten pounds per year.
Today, sugar consumption is basically an order of magnitude higher, on average in the 80+ pounds / year range, with over a hundred pounds a year very common. That’s about a half a cup of sugar every day.
And sugar (in one form or another, whether cane or corn or honey or whatever) is in virtually everything today, from sodas to ketchup to hot dogs to the hot dog buns themselves.
So it’s pretty clear that people don’t actually grow out of a taste for sugar. Further, there’s some strong indications that a childhood taste for sugar is cultural, as children who grow up in cultures without candy often don’t care so much for it.
There’s also excellent reason to think that the current epidemic of the metabolic condition, especially including obesity and adult onset diabetes, is due in large part to sugar consumption.
That Kevin now avoids sugar is great, not bullshit. The notion that humans are born with a taste for sugar that they later grow out of, on the other hand….
Cheers,
b&
I should also point out that I’m not fanatical about sugar, I still eat a small slice of my birthday cake.
I also make a wicked black bean garlic sauce with maple syrup.
Total abstention isn’t necessary. Just bring consumption back in line with pre-industrial levels and you’ll be fine. Limit yourself to no more than a teaspoon (5 grams) total sugar per meal and you should be fine. If you don’t indulge at every meal, you can occasionally overindulge with a bit less guilt.
Sounds intriguing! I don’t suppose you’d care to share the recipe…?
b&
Peanut oil
Black beans
Garlic
Sugar
Stock
That’s the standard recipe that I picked up somewhere. Maybe on Google.
I use a less flavourful oil and substitute maple syrup for sugar and vegetable stock for chicken since the black beans have enough umami.
And a big teaspoon of sambal oolek since it improves everything* it touches.
*Maybe not ice cream.
Thanks for that!
You led me on a search that wound up with me ordering some douchi. One of my favorite dishes is ma po tofu, and the ingredients for homemade black bean sauce aren’t all that different from what I already use for the sauce. So, I’m thinking that I’ll simply use the beans and leave out the canned sauce…and, I rather suspect, I’ll be even happier with my favorite dish…I love the black beans, but the rest of the sauce in the jar is merely not bad.
Cheers,
b&
That reminds me, six months after cold turkeying the sucrose, I was fifty pounds lighter.
— and that’s very typical.
b&
Same here.
20 odd years ago I cut right back on sugar and ended up losing 18 kg.
Everyone thought I had HIV as unfortunately for me, my body leaves my stomach fat til absolute last so my face ended up rather gaunt even though my body fat percentage was still higher than ideal.
Another great bonus is at 47 my dentist is always surprised at how healthy my teeth are.
I’m 47 that is.
As Homer Simpson says, “First you get the sugar, then you get the power, then you get the women” 😀
Hmm…of all the people I can think of to get advice on how to get power and women, Homer Simpson sure isn’t one of them.
But I can easily imagine him being an expert on where to get the sugar….
b&
He’s got Marge and her daughter served as President of the United States.
I’m amazed at how much sugar there is in some allegedly savoury foodstuffs, such as tomato sauce [US: ketchup]? Is there some kind of arms race going on between sweet and bitter?
Oh yeah, sugar is in everything – ketchup, mustard, relish you name it, it’s there!
The taste for sugar is present at birth in human infants. This is pretty well established. I can provide references to anyone interested but it’s easy to Google.
I haven’t grown out of my sweet tooth, and I wish I could!
Try satisfying your sugar cravings with fresh veggies — all-you-can-shove-in-your-face fresh veggies. Celery, radishes, broccoli, greens, carrots, sugar snap peas, you name it.
At first, it’ll take a lot of veggies to satisfy the cravings, and maybe then not even entirely. If so, think of the veggies as a chore, something that’s just gotta get done like folding laundry. Eat fresh veggies until either you don’t want the sugar or you’re stuffed so full you can’t eat another bite of anything.
After a week or so the sugar cravings should be greatly diminishing, and you’ll find that it doesn’t take anywhere near as much veggies to make you feel full. Not much long after that you’ll start to realize that all sorts of unsweetened foods are actually already sweet, and pure sugar will taste unpleasantly cloyingly sweet.
And from then on, you should be good to go.
Read labels and ration yourself to a teaspoon of sugar per meal — and make the teaspoon count. My breakfast this morning will include a couple small slices of (homemade whole wheat sourdough) toast, with a half a teaspoon of honey on the one and a half a teaspoon of jam on the other. And I really, truly will enjoy it but not wish for more sugar.
The rest of breakfast is going to be a couple slices of bacon, a bit of cottage cheese, and whatever fresh veggies I have in the ‘fridge that grab me…probably some cucumber, some baby carrots, and a stalk of celery, with a bit of (homemade, no sugar) gorgonzola sour cream dressing for dipping. (You’d be shocked at how much sugar goes into commercial salad dressings.)
Cheers,
b&
And whatever you do don’t go from regular soda to diet! Artificial sweeteners fork up your system. I tried that switch and it made me ravenously hungry.
There’s some evidence that the sweeteners by telling your brain that there’s sugar coming releases insulin that goes around looking for the sugar that isn’t there and a whole cascade of nastiness happens.
You really have to give up the idea that sweetness is a regular part of your day. Save it for special occasions.
Diet coke has some sort of medicinal ability for me when I get migraines. I’ve checked with my fellow migraine sufferers and they say the same. I suspect it is the caffeine and perhaps the thirst quenching the fizziness seems to provide (I get very thirsty when I get a migraine).
I drink mainly diet soft drink, very little naturally sweetened. I haven’t noticed an increase in hunger, but my BSL is higher than I’d like.
Let me echo the warnings against alternative sweeteners. They generally need to be metabolized by the liver, which is generally a bad thing except in small quantities. The liver is where toxins go to be broken down into stuff that your body is better equipped to deal with, but what’s left over generally isn’t stuff you want a lot of in your body, either.
Fructose, for example, is metabolized in the liver into a bit of glucose (which your cells can use for energy) as well as non-trivial proportions of fats and low-density cholesterols.
Now, your body actually needs small amounts of all of that to function properly. And the amount of fruits or honey or whatever that you would have eaten in a pre-industrial society would have given you all that you need of that stuff — along with, at least in the case of fresh whole fruit, all sorts of other good nutrients such as fiber and various vitamins and what-not.
But the quantities of sugar (and the purity of its form) that modern Americans eat cause the liver to produce prodigious amounts of fat and cholesterol, resulting in the metabolic condition.
I don’t know specifically how the body metabolizes aspartame or whatever, but I can’t imagine the byproducts actually being healthier than the (already not-good-in-excess) byproducts of sugar.
Diana, you might want to consider some alternatives to diet coke for your migraines. Try regular coke, first; that’ll tell you what role, if any, the sugar plays. Then try something else with caffeine, such as coffee or tea — or even a diet pill containing caffeine. Also try just regular soda water / Perrier / etc.
If it turns out that it’s the caffeine, think about using unsweetened black iced tea. It’s also got theobromine in it, which is likely to also be helpful. And I think your liver will thank you.
If it’s just the cold fizzy drink that does it for you, then you can’t go worng with plain carbonated water, perhaps with a wedge of lemon squeezed into it. To your body, that’s no different from uncarbonated water, which is the best thing for humans to drink.
Cheers,
b&
And then there’s the hidden sugar. I.e. manufacturers don’t write malt sugar on the ingredience list, but maltose. If you want/need to avoid sugar in any form, you almost need a degree in chemistry. Or a list with the “translations”.
It’s actually simpler to just avoid (not eliminate, but avoid) prepackaged foods in the first place.
Cooking is easy, quick, and cheap.
It takes about fifteen minutes of my attention over the span of a few hours to make a loaf of bread — and I’m the crazy type who grinds his own flour. Most meals take me about as long to make as it does to wait for the pizza delivery. Or, like the bread, they take only a few minutes of active attention, with me doing anything but cooking during most of the time that they’re cooking. Chicken soup, for example, takes about five minutes from grabbing the pot from the cupboard to me walking away for the better part of an hour, and then another five minutes to de-bone the meat and otherwise get what I’m not eating right then and there into the ‘fridge. Turning that into all sorts of other meals is again quick and easy.
The results taste better, are healthier, and — even if I splurge on insanely overpriced stuff from Whole Foods or wherever — substantially cheaper than the industrialized alternatives.
There is a time when eating out or when there are circumstances that having prepackaged foods makes sense, but it’s so rare that that sort of thing makes sense as the rule rather than the exception. Most families would be a lot happier if they cooked for themselves.
Cheers,
b&
Fascinating but I don’t get how this is clever. It seems to me that the optimum strategy from the roaches point of view would be to evolve an aversion to the poison, not the attractant. All you have to do now is switch attractants and the new roaches will go the way of the old roaches.
Natural selection just uses what genetic variation is available. It might not be physiologically possible to make the poison taste bad, or there might not simply have been any genetic variation for aversion to the poison itself. By “clever”, I meant “unexpected but effective.”
I knew that already. Evolution doesn’t have a mind, it can’t think or plan, it just goes with what works and if chance doesn’t give it something to go with then nothing happens.
I know a fellow who believes that god guides evolution. I said if that’s true, he’s using AppleMaps.
Here here, this article is badly titled. It should say “evolution has no intelligence: but can sometimes be effective for life to exist, only some of the time, on only some parts, of one of many many planets that we know about.” Lazy journalism.
Ok, telecastermasters, that’s two rude comments in a row. You are simply a clueless person who has no idea how to engage in civil discourse, nor to avoid insulting your host. Those are the rules here, by the way.
I suggest you frequent some other website from now on.
Since you’re so concerned about figurative use of language, I’ll point out that, if evolution can’t be “clever”, then journalism can’t be “lazy”.
Aside: Now, having said that, telecaster’s comment can also be read as pure sarcasm. The suggested alternate title is intentionally unwieldy and not meant as a real suggestion. Perhaps he’s saying, “well, /of course/ Jerry didn’t mean “clever” in a literal sense, but he used it as a convenience of language – I mean, just look at the absurd alternative!”
Or perhaps he’s just being rude…
I think the makers of Fabreze may be in line for a Nobel Prize in Chemistry this year. Using their chemical savvy, they were able to trick the brains of millions into sensing that a garbage can full of rotting KFC parts and kitty doo-die smelled like a bouquet of violets freshly picked on a Himalayan hillside!
That’s quite a feat.
Febreze itself is odorless. Early market tests found that “housewives” would use the test product and then afterward spray some perfumy scent in the same room. The market research found that users needed a signal that they’d accomplished their goal.
Likewise toothpaste leaves a tingly feeling in the mouth because Pepsodent discovered that adding something to cause that tingle on the tongue made people think their teeth were cleaner even though it had nothing to do with it. They soon outsold all other brands and now every toothpaste brand has that tingly feeling (except Tom’s of Maine, which I can’t stand despite knowing I don’t need a tingly feeling!)
(I can’t remember where I read this – either Dan Ariely’s book, Predictably Irrational, or Lehrer How We Decide)
You sure it wasn’t just by reading The Coconut Effect page on TVTropes?
On the subject of article access, I’ve heard suggestion that your local university (wherever you might be) might offer free guest-access WiFi, and that, if so, you might have free access through said WiFi to all the university’s journal subscriptions.
On the cockroaches…seems to me the next step is to figure out a bait that includes everything in the typical human home that might attract the roaches in the first place. In the short term, it should be more effective at attracting roaches to the bait. In the long term, it should cause the roaches to evolve distaste for what humans like, thus removing the incentive for roaches to look for food in our homes in the first place.
I’ll also note that I’ve never seen a cockroach inside my home ever since I moved here about four years ago. Part of that I attribute to the boric acid my Mom helped me spread along the baseboards as I was putting in the floors, but a good deal I attribute to Baihu. Even flies have a very short life expectancy in my home. A cricket that starts chirping indoors will become a snack in about a minute, and I’ve never actually seen one of them, either.
Cheers,
b&
In 13 years of living here, we’ve never had roaches until this spring, courtesy of the next door neighbors. The roaches show up in or near the cat litter boxes (possibly looking for humidity as much as food) and none of my cats will have anything to do with them. The smell must be a turnoff. But the roaches seem to be succumbing to the traps so far – but these are Blatta orientalis (not the same species as the ones in the paper) and may not have evolved in that direction (yet!).
I agree with you about the baits – obviously they need to include a broader spectrum of attractants.
Disheartening to think I’ll have to add caviar instead of brown sugar to my boric acid bombs. Arthropodic conquest is a mug’s game.
You can hear more of this here:
http://www.sciencemag.org/content/340/6135/995.2.full
Well that explains taste preference in humans – those people that don’t like what I like (ice cream, chocolate, potato chips, diet coke) are all just wired up wrong. 😀
One of my cousins never had a sweet tooth. I always thought he was a freak!
Yes I’ve met those strange people myself….very unnerving. 🙂
I know a Toronto policeman who doesn’t drink coffee or eat donuts!!
No way! That sounds like a myth! 😀
Not a myth. He’s my stepdaughter’s husband.
Yes, I was being facetious
Of course
More evidence that I’m “not neurotypical.”
I hate chips and soda, and was allergic to chocolate for many years and now enjoy it only in small amounts in specific foods.
Ice cream is another matter. I love it as long as it’s rich and not too sweet. But good heavy whipping cream, unsweetened and straight from the carton, is even better. Preferably with fresh blackberries.
That’s a relief. I’ve been worrying that you weren’t eating your vege-tables.
Thanks for the refs Jerry! I know at least one of them will end up in my literature review.
Reblogged this on Science and Atheism and commented:
good stuff here
Wow. Thanks, Jerry, for keeping this a sane and intellectually stimulating site. The internet is rife with rancid “clever” posters who insult and demean and take out their little aggressions on comment threads. This itself acts as a repellent (who wants to visit bad company?) I like the atmosphere here, free of the rude, showboating “I call bullshit” commenters.
I agree – I really liked this article in particular and I’ve often recommended this site with the description of it being full of smart commenters that are polite even when disagreeing (especially because Jerry vigilantly jettisons the rude ones).
I am confused. If the bait killed those who ate it, how can there be changes in their taste?? Dead roaches do not reproduce. So how do they react to the sugar??
Or: what am I missing??
Vivian Bregman
Opposite – the ones who avoided it reproduced thus passing on the stuff that caused them to avoid the sweet stuff.
Yeah, what Diana said. But to expand – some roaches (or at least one) naturally are averse to glucose. Over time, they leave more offspring than the ones who like glucose (because of the traps). The genes that cause glucose aversion then become widespread in the population. The roaches have evolved to have an aversion to glucose.
German roaches, eh? Does this mean our good old American roaches just aren’t smart enough to evolve this too? No wonder this country is can’t compete.
Knowing the predilections of our esteemed host, at first I happened to read that image text as “Panglossia”. Apparently I was preset to think that cockroaches who could avoid poison were inhabiting “the best of all worlds [for them]”. (Don’t blame me though, I had no free will in the matter.)
Ah, I just realized a situation where evolution _is not_ “smarter” than me.
That is when it evolved my non-free will mind, which must be about as smart as me. (Give or take some lumps of sugar fuel.)
Doesn’t that mean evolution resulting in human brains is the least “smart” thing it could do? I don’t think creationists would be happy with such a conclusion. =D
“cockroaches avoid poison baits by rewiring their taste system”
I doubt it. Cockroaches don’t seem to do a lot of rewiring.
More likely, cockroaches who avoided poison baits already HAD a mutated taste system, and they survived to reproduce.
There was no intention to rewire the taste system. Evolution is not clever. This lazy communication is what gives creationists easy ways to attack it.
Oh, thank you SO much for your correction; I had no idea that evolution worked that way! And here I thought, silly me, that I was simply using shorthand that EVERY READER OTHER THAN YOU understood.
Randy, you haven’t learned enough to be polite to your host here, and you’re insufferably pedantic. I suggest you frequent other websites that either allow or encourage such rudeness.
Jerry, I’m dismayed. You ripped a guy at the top of this comments section for his abusive treatment of a fellow commenter, and then, when it suits your needs, you get sarcastic and brutally rude with a reader who has made a good point. (Ignorant is not bad…unless Randy’s a repeat pedant or ignoramus. Maybe you should have a standard link to a FAQ to respond to his point?)
How do I know it was good? I came in to make the same basic point about the impact of the headline. 🙂 I wanted to read first, so that I didn’t repeat an observation already made. To the point:
You have used the “shorthand” explanation previously, as justification for headlines that imply evolutionary intent, or suggest (to the uninitiated) that a change took place within a single generation, or even within a lifetime. I know what you meant. You know what you meant… But the “I” that I was ten years ago before heavily devoting myself to reading evolution texts would have taken your headline wrongly.
I’m of the same mind as Randy that this shorthand gives fodder AND misunderstanding to those less well versed than you, and that if you want to enlarge the percentage of people who “believe” in evolution, you might achieve that goal with headline writing that doesn’t imply completely false evolutionary mechanism or time frames.
I mean this respectfully: I wonder if you might take it on as a personal challenge/project to come up with BETTER shorthand that is not hamstrung by the limitations of the current shorthand.
I don’t mind honest differences of opinion, but using the word “lazy communications system” is itself rude, the implication that I don’t know how evolution works is pedantic, and his explanation was condescending. His point could have been made politely and without lecturing, but was snarky.
Here’s an alternative way to say what was said:
“Jerry, it’s possible that creationists might quote-mine you because you’re using shorthand that smacks of teleology, like “cockroaches rewired themselves”. Aren’t you worried about that?”
Now that would have gotten a polite response.
Some people, however, say whatever they think without considering how it sounds to the recipient. The internet is really bad at allowing people to be thoughtless, haughty, or snarky in this way, but I won’t tolerate it here. One of my rules is that commenters should be polite to the host and to other commenters. If those guidelines are abrogated, I reserve the right to get annoyed. (I grant that sometimes I miss some rule violations.)
Back on topic, I seriously doubt that creationists will quote-mine me for this shorthand, for they haven’t done that before. They have richer veins to mine on this website, and you can see those over at Evoluton News & Views. But I’m always willing to explain things to a puzzled reader if he/she is misled and I have the chance to respond.
Then Randy, go and find out if it is a pre-adaptation or caused by de-novo mutations. For the rest of us this is of lower importance, as the result stays the same and is caused by evolution by natural selection, and is a very intruiging case.
A bitter irony when discussing our sweet tooth, be it genetically or culturally conditioned, or both: without our common penchant for sucrose, two Nigerian-born, alienated and possible deranged men may probably not have been stranded in London, not gyrated towards the Islamist quagmire, and ultimately not hacked a British soldier to death in a fit of murderous frenzy.
As Yale anthropologist Sydney Mintz (Michael Buratovitch, take note: a Marxist and a Jew) observed, “Sugar followed the Koran” (1). Another loop closing: the spread of sucrose may be among the most lasting consequences of the Arab conquests. In Cairo, sugar was a dietary staple by the 11th century. Venice monopolised the north-bound Mediterranean sugar trade and dominated the European sugar trade until the 16th century. Venetians pioneered sugar cane plantations on Crete and Cyprus, using forced labour when manpower became scarce, corvée and, increasingly, slave labour. The pattern was duly noted and repeated on a large scale by the Portuguese on their Brazilian plantations; later, by tutti quanti in South, Central, and North America and the Caribbean(2). Cheap sugar from the Americas ruined the Mediterranean sugar industries. Rough but effective improvements in the large-scale refining of sugar (the “Spanish train” and the “Jamaican train”) produced cheap sugar and made the triangular trade viable. The rest is history.
Evolution is smarter than we are. Cockroaches will probably outsmart us. They can out-evolve their sweet tooth. We may not be able to overcome our addictions, any more than we are able to overcome our ideologies.
(1) Mintz, Sidney W. 1985. Sweetness and Power: The Place of Sugar in Modern History. New York: Penguin Books.
(2) Galloway, J. H. 1989. The Sugar Cane Industry: An Historical Geography from Its origins to 1914. Cambridge, Massachusetts: Cambridge University Press.
The BBC has been running the story with very funny footage of cockroaches refusing to eat the glucose, using body language indicating all kinds of disgust on their “faces”.
I noticed their story used the expression “Natural Selection” but not the E-word. Do you think we could sneak around the fundies by doing likewise? It’s the word “Evolution” that seems to be like glucose to them. Likewise, it seems to be the A-word that bothers them, rather than lack of belief in supernatural beings.
WOW!
This is truly astonishing, that a cockroach can evolve to taste glucose as aversive (bitter) is really extraordinary. Though I notice they still taste it as “sweet” as well as “bitter”, so the glucose receptors are still wired to “sweet” while glucose stimulates bitter responses at the same time. That makes sense actually, because sweet is a far less varied taste than bitter. Enormous numbers of chemicals taste bitter compared with other tastes, so it is presumably a more evolutionarily malleable taste, in order to keep up with new poisons created by the desire of plants and animals not to be eaten. Most bitter chemicals in plants are not actually poisonous, but they are treated as though they are and avoided just in case. Fascinating stuff!
Reblogged this on Mark Solock Blog.
Of course many of you know about the classical genetic variation in people for being a ‘taster’ versus a ‘non-taster’ for the bitter chemical phenylthiocarbamide (PTC). Tasters have a receptor for this chemical, and non-tasters are homozygotes for a recessive mutation where they do not taste this chemical. So here again is an example of a genetic variation in a population for differences in taste.
I read somewhere that our ability to talk is predicated on our ability to sing, and our ability to sing has some sort of sexual selection basis, like birds. People who lose the ability to talk for neurological reasons often can still sing.
I can’t remember where I read this at, so take it with a grain of salt.