قالب وردپرس درنا توس
Home / Lists / An ancient shipwreck was transformed off the coast of Greece into an underwater museum

An ancient shipwreck was transformed off the coast of Greece into an underwater museum

Whether brown or blonde, in a straight or naturally curly hairstyle, the hair that grows out of our heads is a fundamental aspect of the human appearance. Our variety of hair types is so ubiquitous that it's actually easy to ignore how weird hair is – not in the sense that your hairstyle is on the wrong side of your nerves.

"When it comes to the uniqueness of man, people come to do all sorts of things – culture, intelligence, language," says Tina Lasisi, Ph.D. student in anthropology at Penn State University, opposite Mental Floss. "[But] We are the only mammals that have hairless bodies and hairy scalp. "

On the surface, our hair types are simple enough, like the fingernails, the hair is mainly protein keratin, which can survive for thousands of years under the right conditions To Ötzi, the 5300-year-old ice man whose clothes, body and hair were preserved when he was frozen in a glacier, and in warmer, wetter, and acidic environments, hair can be broken down within weeks.

But that's just it What Hair Are. Why we have different hair types and how they are created is a mystery that scientists ger just start unraveling.

Why do we have hair on our heads?

Some researchers have tried various hypotheses to explain hair growth patterns in Homo sapiens and why they differ so dramatically from our close relatives as chimpanzees. The loss of body hair meant that we could sweat more, a cooling mechanism that "has helped to facilitate the dramatic enlargement of our temperature-sensitive organ, the brain," writes anthropologist Nina Jablonski in Scientific American . Other researchers hypothesized that hair on the heads helped hominin regulate body temperature when they became bipedal and traveled long distances. Basically, the scalp hair has created a kind of built-in hat.

Normally hair does not stay like hundreds of thousands of years like fossilized bones. If scientists want to answer the question of how our hair evolved from whole body fur, they need to explore the human genome ̵

1; and Lasisi has found that surprisingly few do. This is partly due to the time and cost of conducting genome analysis to find out which genes affect hair production. But it is also because, according to Lasisi, it was not a question of former (male) scientists.

"They said," Oh yes, hair, it's sexy for women, it's probably sexual selection. "But there was no effort to consider it as a unique human trait because it was more interested in our big brain, bipedalism and so on," says Lasisi.

How did different hair types come about?

Even the lack of categorization for hair types is the tale, unlike what your shampoo bottle says, there is no real classification system for different hair types, at least not yet.

"Most mammals have straight hair. [in African and Melanesian populations] has this tightly wound configuration, and we tend to talk about hair as smooth, curled, curly hair, and in some cases frizzy, "says Lasisi," but it's as if we're trying to do genetic studies on body size by saying that there are small, medium and large people who are now finding out which genes are involved. "

With a In other words, before she could even try to answer the question, which genes determine the texture and color of hair, Lasisi had to work out a system for defining these hair textures and colors. Lasisi began by creating a classification system that she hopes to publish. This is based on a microscopic analysis of the curl radius and the exact measurement of melanin in the hair. She then tried to answer the first of many questions: Whether tightly-knit African hair evolved in response to the hot environment. While this research is still ongoing, she says the results may indicate something out of the ordinary – the thicker the hair, the better it will be isolated from the heat.

What is the oldest human hair ever found?

On On the rare occasions when hair is kept in the fossil record, this can be an incredible source of information about the health and behavior of our ancestors. In 2009, Lucinda Backwell and her colleagues described the discovery of seemingly human hair in fossilized hyena capsules (also known as coprolites) from more than 200,000 years ago – the oldest evidence of human hair to date. Five years later, Backwell and others followed with an examination of 48 hairs of hyenoprolins that identified several mammalian species. The presence of all these hair types means that the hyenas have been caught from many different remnants, including humans.

"They told us a lot about coprolite human hair because there were no bones," says Backwell, anthropologist at the University of Witwatersrand in South Africa and Instituto Superior of the Estudios Sociales, CONICET in Argentina, who informs Mental Floss by e -Mail. They revealed that 200,000 years ago humans shared the environment with large herbivores such as the impala, zebra, kudu and warthog in southern Africa. Unfortunately, all the keratin in this hair sample had been replaced with calcium carbonate that did not contain DNA for all scientists. "The first prize would be to extract DNA and find out if the hair belonged to a modern or archaic human, or even to someone like Homo naledi with its primitive qualities and young age," Backwell said. In addition to identifying the exact hominin species, DNA from such a hair sample could make a major contribution to telling more about the relationship of the different species among themselves.

Backwell has also studied high altitude human hair cave site in Argentina, one of the best environments to protect hair because it is "cool, dry, dark and with a neutral pH," she says. Like the coprolith hair in South Africa, the dating and identification of hair in Argentina will help Backwell and others to understand the spread of humans around the world.

How can hair illuminate the story?

When people are exposed to substances on the Internet, their hair will retain some of the chemical signature of these substances. Hair found in ice, amber and on mummies from arid regions around the world has allowed researchers to learn fascinating details about the inhabitants of certain regions.

In 2013, archaeologists from the University of Chile analyzed 56 mummy samples found in the north of Chile. Using gas chromatography mass spectrometry (a tool that identifies various substances in a sample – and is also used for drug testing), they found that people were continuously consuming nicotine-containing plants from 100 BC. Until 1450 BC Had smoked. "Overall, these findings suggest that the consumption of nicotine was performed by members of society as a whole regardless of their social status and status," the researchers wrote in their study.

Another group of archaeologists collected hair samples from 40 mummies found in Peru, Chile and Egypt to analyze pre-industrial mercury concentrations around the world dating back to 5000 BC. BC until 1300 BC Range [PDF]. Their results, published in 2018, indicated a much lower level of mercury in the environment than in industry. The researchers also found that each group's diet determined the actual level of mercury exposure – the Chilean mummies had higher levels of seafood, while the Egyptians who ate land animals had the lowest.

For now, the riddle of hair development remains partially unresolved. But the next time you're in the salon, look in the mirror and remember: hair is part of what makes us human.

Source link