Why are animals in constant search of sweet food?
Answers
Answer:
If it helps you please mark as BRAINLIEST
Explanation:
No preference is so quick to form, and none so hard to lose, as a baby’s love for sweets. Give a newborn a drop of sugar water when he’s hours old, and he’ll suckle. At a dental school in Jerusalem in the early 1970s, a scientist named Jacob E. Steiner doled out sucrose to 175 infants before they’d had a drop of mother’s milk and saw clear signs of satisfaction: The babies showed “a marked relaxation of the facial muscle,” he wrote, and “a retraction of the mouth’s angles resembling a ‘smile.’ ” Then he tried the same experiment on several babies born without a cerebral cortex and found the same result. The joy of sugar needs no cogitation; it scarcely needs a brain.
Yet we still don’t know so much about the science of sweet taste. It was only in 2001 that neuroscientists found the human sweet receptor: a twinned set of proteins that straddle the membrane of a cell and dangle out like miniature maws. When a molecule of sucrose flutters by, the proteins’ hinged, external bits — called Venus Flytrap Domains — snap shut and send a signal from the mouth to the lower portions of the brain: There’s something sweet in here, keep eating!
But in other animals, the love for sugar isn’t quite so ingrained. Last May, a team of entomologists showed that sweet-tasting baits used by exterminators have nudged cockroaches off glucose. They’ve now evolved in such a way that sugar stimulates receptors that once sensed only bitter flavors. Their wires crossed, roaches now find the baits appalling. Among mammals, preferences for sweet will often match a species’ diet. Cats and other felines, for example, have long since lost their sugar habit: Venus flytrap receptors serve little purpose for these meat-eaters and have degraded in the random drift of evolution. Dogs, on the other hand, are more catholic eaters, so they still have the taste.
Some mammals have lost the capacity for sensing either sweet or savory: In 2012, a team led by Peihua Jiang of the Monell Chemical Senses Center in Philadelphia found this to be the case among marine mammals like Asian otters, bottlenose dolphins and sea lions — species that tend not to chew their food. “It kind of makes sense,” says Paul Breslin, another taste physiologist based at Monell and Rutgers University. “If it looks like a fish and swims like a fish, and it’s hard to catch, they’ll swallow it whole. So they don’t need to taste.”
But what about substances that mimic sugar, like the noncaloric sweeteners many of us depend on? The human flytrap clamps down on sugar, but it also grabs Sweet’N Low and Splenda and lots of other chemicals — both artificial and natural — that approximate the flavor. Do other animals have the same response? If a dog likes the taste of Coca-Cola, will it show the same response to Diet Coke?
It turns out that rats and mice, at least, respond to saccharin, the functional ingredient in Sweet’N Low, but they aren’t moved by aspartame, the major sweetener in diet sodas. In 2001, the physiologist Dieter Glaser tried this same test on a set of swamp wallabies from southwestern Australia. The little marsupials could detect some forms of sugar (glucose, fructose, sucrose) and not others (galactose, lactose); but when it came to sugar substitutes, they had no responses whatsoever. Glaser tried saccharin and aspartame, as well as sucralose, stevia, acesulfame-k, neotame, licorice and several other sweeteners.
Glaser has run similar tests on fish, hedgehogs, elephants, horses, cows, sheep, pigs, mice and birds, to try to figure out when our own sweet-taste receptor might have picked up its habit of grabbing at so many different chemicals. For one study, he mapped the response to sugar substitutes in different primate species. Humans, apes and Old World monkeys can all taste aspartame, he found, as well as another artificial product called neotame. But New World monkeys, tarsiers, lorises and lemurs are insensitive to it.
Even modern humans show some variation in receptivity to taste artificial sweeteners. Monell’s Breslin notes that among Homo sapiens, the taste for sweet is universal, with only slight variations in intensity from one person to another. That’s not true for sugar substitutes, though. (It’s safe to say that you and I both like the taste of sugar, but we may have different takes on diet soda.) “The pressure to maintain sensitivity to sugars has been maintained throughout the history of evolution,” Breslin says. “The ability to detect glucose and fructose and sucrose is mandatory because that’s what plants make. You have to detect those. But there’s nothing controlling whether you’re going to be able to taste aspartame or saccharin or cyclamate or acesulfame-k or sucralose. The fact that we respond to those at all is just sort of an accident.”
Answer:
Please Mark Me As Brainliest!
Explanation:
The enjoyment they feel from eating something sweet is facilitated by the same morphine-like biochemical systems in the brain that are thought to be the basis for all highly-rewarding activities. From an evolutionary standpoint, our survival depends on our ability to take in energy from our diet.