Why does skin come in different colors? Detailed answer

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Why does skin come in different colors? Detailed answer

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Why does skin come in different colors?

The color of human skin depends on three pigments, or dyes, found in the body. The first of these is melanin, which is a brown substance. The second is carotene, a yellow substance. And the third is hemoglobin, a red substance found in the blood. Differences in skin color among different races on earth depend almost entirely on the amount of melanin in the skin.

We know that under the influence of sunlight, the skin produces more melanin, which is why people living in hot climates have darker skin. If we turn to more distant times, we will see that three groups of people were developing simultaneously. One of them is the Mongoloid branch, in which the skin color of the people included in it ranged from yellow to brown.

Another group are Negroids, with dark skin of various shades. And the third group - people with white skin. Over the centuries, these groups often mixed with each other. This applies to a lesser extent to the Negroids, who until recently developed in isolation. Despite this mixing, it was generally accepted that humanity is divided into five races that have their own distinct characteristics: white, Mongolian (yellow), Malay (brown), Negroid (black) and American (red).

Nowadays, scientists no longer believe that humanity can be divided into five separate races. Too many color differences, even among people of the same origin! For example, the white race is a mixture of three main groups: the Mediterranean, with dark skin, the Nordic, which consisted of people with fair skin, and the Alpine, which included people with rather dark skin!

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

When did humans start domesticating animals?

Starting to domesticate animals, man took one of the greatest steps on the path to civilization. Since tamed animals provided man with food and confidence in his meat reserves, he no longer depended only on hunting. Now he could settle down in some kind of permanent home, acquire property and begin to build a new type of society.

No one knows for sure when certain animals were tamed. The only thing that can be said: it was in ancient times. After the dog came cattle, sheep, goats and pigs. These animals, like pack animals such as the camel, yak, donkey, were originally tamed not in Europe, but probably in Central Asia.

It is not surprising that among the very first domestic animals, in addition to the dog, which helped man in hunting, there were those that could provide him with food supplies. Cattle, sheep, goats and pigs provided meat and milk. The birds probably soon followed them. It seems that the goose was the first to be tamed of all domestic poultry today, followed by the duck. Both of these birds were common in ancient Egypt. By the way, pigeons, in addition to being eaten, have served as messengers since biblical times. The prehistoric inhabitants of North America raised turkeys in large numbers. Apparently, rabbits were first bred only for meat.

Animals that serve people as pack animals were tamed later than goats, sheep and cattle. Perhaps the first beasts of burden were the donkey and the camel. The horse was domesticated later.

In ancient times, elephants were tamed and put to work by man. A lama in South America has carried weights for several centuries.

Cats were domesticated in Egypt about 3600 years ago.

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Soil batteries for storing solar energy underground 02.10.2022

British scientists have proposed an interesting concept for storing solar energy underground. The idea is to create batteries for storing and transmitting "green" energy based on microbes living in the soil, namely: to stimulate certain microorganisms in the soil, using recessed electrodes to generate electricity from solar panels.

According to Dr. Michael Harbottle from Cardiff University, the project could be massive. The scientist believes that it is simply necessary to use a rich natural resource, the soil, to solve the problem of renewable energy storage.

The process of transferring energy in soil is somewhat similar to photosynthesis, when plants take in CO2 and turn it into oxygen. Some photosynthesis processes take place underground. Underground living organisms, according to the researcher, will be able to use the energy received to reduce carbon dioxide and create a more complex chemical - acetate. Harbottle says that acetate can store chemical energy. If the microbial fuel cell is activated, the bacteria will begin to break down the acetate.

Acetate in large quantities can harm other organisms. And the scientist is still thinking about how to solve this problem, but the method itself does not require resource-intensive or dangerous chemicals, such as lithium, used in other battery technologies.

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