Why do people have hair on their bodies? Detailed answer

BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
Free library / Directory / Big encyclopedia for children and adults

Why do people have hair on their bodies? Detailed answer

Big encyclopedia for children and adults

Directory / Big encyclopedia. Questions for quiz and self-education

Did you know?

Why do people have hair on their bodies?

Birds have feathers, mammals have hair, and humans have hair. It is believed that feathers and wool made it possible for birds and mammals to go so far in development from their common ancestors - reptiles. There are only two places on the human body where hair does not grow: on the palms of the hands and on the soles of the feet. The hair on the rest of the body is thought to be a remnant of the thick hair that our prehistoric ancestors had.

The body of a human cub in the womb, at the age of about a hundred days, is covered with thick hair. And after another hundred days, this wool, called embryonic hair, falls out. This wool is replaced by the soft down of a newborn baby. Then, during puberty (for boys - at fourteen years old, for girls at twelve), the hairline is finally formed. Hair growth in an adult is regulated by the work of the gonads.

In men, certain hormones cause hair to grow on the face and body while slowing hair growth on the head. Female hormones act in exactly the opposite way. Science still hasn't fully explained why we need hair. We can say that the hair on the eyebrows, eyelashes, ears and nose protect important organs from dust and insects. The beard of men in prehistoric times helped to distinguish a man from a woman - even at a distance - and gave him a courageous, warlike appearance.

According to Charles Darwin, the fine hairs on the body help to release perspiration. An adult male has from three hundred to five hundred thousand hairs on his body. Blondes have the thinnest hairs, and there are more of them than brunettes and, especially, redheads, who have the coarsest hairs, and they are the least.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

What are the main genres of fine art?

A portrait is a recreation of a human personality, an image of a person or a group of people.

Landscape - an image of pictures of nature, virgin or mastered by man.

Test your knowledge! Did you know...

▪ Why did people believe in the existence of witches?

▪ Why does the highest peak in the world have an English name?

▪ Who initiated the changes in the Animal Farm cartoon compared to the original story?

See other articles Section Big encyclopedia. Questions for quiz and self-education.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Seagate 8 TB hard drive 21.12.2014

Seagate Technology has begun mass shipping the world's first 8TB hard drive. The cost of the drive is $260. Thus, the price of 1 GB of capacity is $0,03, says ExtremeTech.

The new drive, made in the form factor of 3,5 inches, is positioned as a tool for archival data storage. It has a record capacity, but the same cannot be said about its performance.

The spindle speed is 5900 rpm. The amount of cache memory is 128 MB. The average read and write speed is 150 MB/s, the maximum is 190 MB/s. Average uptime - 800 thousand hours.

Model ST8000AS0002 consists of 6 magnetic platters, each with a capacity of 1,33 TB. An additional 330 GB was provided by Shingled Magnetic Recording (SMR) technology, without which the platter's capacity would have been limited to 1 TB.

SMR technology allows you to overlay tracks on top of each other, so that the recording density of information increases. This technology has been mastered so far only by Seagate. In turn, Western Digital fills the cavity of hard drives with helium. The gas reduces friction and makes it possible to reduce the distance between the plates without causing overheating (this method allowed us to achieve a capacity of 6 TB).

Both methods are already close to technical limits. Therefore, at the next stage, manufacturers plan to move to the technology of two-dimensional magnetic recording (Two Dimensional Magnetic Recording - TDMR).

The Seagate 8 TB hard drive was announced in August 2014. The drive will be available for sale at the end of 2014.

Other interesting news:

▪ Car video camera 360 M600 Dash Cam

▪ Remote speed limit in Tesla vehicles

▪ Elevator test tower

▪ Smartphones from ViewSonic

▪ Smart planter PAU

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site History of technology, technology, objects around us. Article selection

▪ article Praise and slander were accepted with indifference and do not dispute a fool. Popular expression

▪ article What is the difference in time between the most extreme time zones? Detailed answer

▪ article Head of Operations. Job description

▪ article Acoustic system for self-production. Encyclopedia of radio electronics and electrical engineering

▪ article Ensuring reliable operation of imported TVs in standby mode. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews