One Left: How great inventions have changed our body and habits
Text:Svetlana Yastrebova
Technologies influence the evolution of man, his behavior and body - it is a fact. We collected 5 unexpected examples, which clearly show how inventions imperceptibly make us different.
Agriculture and caries
WHEN: 10,000 years ago
WHAT CHANGED: caries has become much more common
Everyone who has lived in the world for more than five years, knows what caries is, and more often than not by hearsay. But before blaming black holes on the enamel for an abundance of sweets and the lack of a habit of brushing your teeth, think about what the scientists from Cornell and Stanford universities managed to figure out two years ago.
The authors of the article compared the genome of Streptococcus mutans - the bacteria that causes caries - to the genomes of several close species that live in the mouth of chimpanzees, macaques, rats and hamsters. It would seem that since chimpanzees are our closest relatives, then our microbes should be as similar as possible. However, it turned out that the closest thing to Streptococcus mutans is not the monkey bacterium, but the inhabitant of the oral cavity of rats - Streptococcus ratti. Apparently, he moved to our teeth and evolved into a new species 10 thousand years ago, when agriculture began to develop and rats began to live side by side with humans around the world.
Another study confirms that caries began to rage precisely at that time. American anthropologists studied the skulls of 39 people who lived on the territory of modern Sudan 8-11 thousand years ago - just when the local population began to master agriculture. And if in older skeletons caries were met only by 0.8% of teeth, then after the appearance in those places of agriculture, the proportion of affected teeth jumped by several times - up to 20%. However, blaming microbes and rats for everything is also not worth it, because no one has canceled the harm of sweets for our smile.
Fork, knife and bite
WHEN: XVIII century
WHAT CHANGED: bite(position of the jaws relative to each other)
What could be more important than food? Knowing what eats an animal, you can imagine how it looks, and vice versa. Now, anthropologists have little doubt that the ability to cook or fry prey allowed the ancient people to chew less, so their jaws decreased, and the brain increased. Along with this, high intelligence and language appeared.
The appearance of forks and knives, of course, did not improve our abilities, but also affected the human body. According to anthropologist Loring Brace, a few centuries ago most people had their upper jaws exactly above the lower jaw. Such a bite option was convenient when it was necessary to tear pieces of meat with jaws. 250-300 years ago, Europeans and Americans often began to use a fork and knife. Therefore, the meat was no longer cracked, but cut, its pieces were put on a fork and sent into the mouth. The procedure seems to us unsophisticated, but the fact is that it was she who changed our bite. One jaw began to go behind the other, because it is easier to remove food from the fork and crush it additionally. Thanks to wooden chopsticks in China, such a bite spread earlier - about 900 years ago.
Light bulb and sleep mode
WHEN: Nineteenth century
WHAT CHANGED: people began to sleep 8 hours in a row without waking up
Night sleep lasted as well as lasts an average of eight hours, but earlier it was divided into several parts. Until Edison patented his invention - the incandescent lamp, the streets were very poorly lit, and not everyone could afford a flashlight to use it safely to get home in the dark. This was used by the gangsters, so most decent citizens preferred to be home at sunset and go to bed early.
However, they rarely slept continuously until morning. In historical documents from Italy, France and the UK, the concepts of "first dream" and "second dream" are more common than just "dream". But later, when electricity and clocks appeared in almost every home, the intermittent night’s sleep became a sub-luxury. People came up with the notions of a regime, a normalized working day, and the idea was born that a person could spend time in vain.
The fact that a night's sleep can be broken apart is often not entirely correct. From here, there are attempts to come up with an ideal mode, in which a person only sleeps for half an hour at intervals of 4-8 times a day, and the rest of the time is alert and efficient. This, alas, can not be. Sleep is divided into several stages, and to sleep, it is necessary that all these stages pass one after the other without a break. It takes about one and a half hours. Therefore, to sleep less is simply meaningless. In addition, drowsiness will not disappear anywhere and will accumulate if you sleep less than 7-8 hours a day. Exceptions are found, but they are too rare.
Ultrasound and sex ratio
WHEN: 1960 is our day
WHAT CHANGED: boys began to be born more often than girls
According to statistics, women who are harboring girls in the early stages of pregnancy are slightly more than those who are preparing to give birth to a boy. But in later stages, this ratio changes. The reason for this is technology, specifically ultrasound.
From the end of the First World War, ultrasound was used so that submarines could navigate in dark muddy water. After 30 years, they discovered that it was possible to find stones in the gallbladder in dogs in this way, and 10 years later it turned out that the human fetus could also be examined with the help of ultrasound. Thus, people have learned by the appearance of the fetus in the womb of the mother to determine its sex.
Mara Khvistendal, author of the book "Unnatural Selection," claims that the world has missed 160 million girls in the past few decades. Their potential mothers, having come to the ultrasound and knowing the sex of the child, preferred to have an abortion. Asia has been particularly hard hit, where men occupy a much higher position in society than women, and the lives and well-being of the latter are not very much appreciated. For example, in China in 2010 boys accounted for 54.14%, girls - 45.86% of the total number of children.
Industrial Age and Lefties
WHEN: 1870 - 1900 years
WHAT CHANGED: right and left handed ratio
On average, there are 9 times more right-handers in the world than left-handers. However, in the UK during the reign of Queen Victoria, the share of right-handers was even more impressive - not 90, but 97 percent. Chris McManus, who together with student Alex Hartigan, watched a huge number of film clips of the beginning of the 20th century, managed to figure this out. The researchers were interested in what kind of hands people are waving from the film. Left-handed people often pretend to be right-handed in order to better fit into the environment, but spontaneous actions, such as greeting with a hand, are not so easy to control. Therefore, this way to find out which person’s leading hand is quite reliable.
Comparing ancient films and modern photos of waving people, McManus found that among the English 120 years ago only 3% of the population used the left hand as the main hand. The scientist connects this with the fact that left-handers were very uncomfortable for schools and factory owners. Machines, as well as the writing system were sharpened by the use of right-handed people. Most likely, the left-handers also ridiculed or even punished for their features, so the unfortunate people didn’t fit into the society worse, less often created a family and had children.
Such a study by Professor McManus is not the only thing. He also compared the position and size of the testicles in photographs of modern people and antique sculptures and came to the conclusion that the asymmetry of the scrotum depends on what hand a person uses more often (by the way, for this work he won the Snobel Prize in 2002). It turns out that the industrial revolution indirectly influenced the sexual system.
The material was first published on the site Look At Me
Photo: 1, 2, 3, 4, 5, 6 via Shutterstock