Why is human appearance close to symmetry?

First of all, it must be the result of evolution, living things are constantly evolving in the survival of the fittest, and the survival of the fittest is the immutable law of nature. I think this is due to two forces that exist on our planet. One is gravitational and the other is drag.

In nature, as long as the body reaches a certain level and can move freely, the creatures are basically relatively symmetrical on the left and right. The first thing a creature has to overcome in action is the problem of gravity, which will act on the object in a balanced manner, so whether it is a two-legged or four-legged organism, as well as a creature without legs, if one side is asymmetrical, it will inevitably seriously affect the action force in the action, and it will not be able to maintain a relatively straight line motion. The presence of the same resistance, like gravity, affects the ability of living beings to act.

In order to adapt to this situation, organisms have to evolve themselves, and over the long years, only the symmetrical species will be more competitive and adaptable to survive. That's why we see all kinds of creatures that look the same on the left and right, including humans. <>

It has evolved to facilitate orienteering. But this is not only humans, in fact, the animals of the world are currently divided into three categories: radiation-symmetrical animals, bilaterally symmetrical animals, and sponges.

Typical radiation-symmetrical animals are usually aquatic creatures that do not need to move quickly, and they can survive in the biological chain by relying on their own lethal**, or special morphological abilities between animals and plants. For example, jellyfish, corals, sea anemones, etc., contain more than 10,000 specific species. Illustrated by Brandenburg biologist Ernst Haeckel, "The Art Forms of Nature".

1904 edition. Humans are bilaterally symmetrical creatures. Symmetry on both sides can provide the function of orienteering, which is convenient for predation and escape. In the small and uninhabitable land, most of the creatures have evolved in this direction, and the proportion is much higher than that of marine life.

Everyone's internal organs and body appearance are relatively symmetrical and reasonable, and in life we find that many foods are actually more symmetrical. In particular, the house frame or furniture structure is a symmetrical structure in the city, and this symmetrical structure can bring everyone a beautiful enjoyment. Then the appearance of human beings is also very symmetrical, and we find that many internal structures are the same, which should have different meanings of existence.

Symmetry in appearanceBecause the symmetry of a human appearance is conducive to daily exercise, it can also help everyone walk, run or swim, and quickly move to where they want to go. These symmetries have a lot to do with not only reproduction, but also for appearance, which means particularly good genetics, involving one's own ability to appreciate. If the eyes are symmetrical, it is decided that there are no blind spots, and it is also conducive to discovering the usual beauty.

Better potencyThe symmetrical organs of human beings are also for life to have a better effect, if it is found to be unreasonable, there is an asymmetrical appearance, which should attract everyone's attention. It will definitely affect other factors in the body, and even other organs will start to grow asymmetrically. It will make you find things that are particularly shocking, make your mobility impaired, and even affect the aesthetics very much, because human beings have many internal organs, and they will have different functions.

Maybe some need one, and some need two and be symmetrical, and asymmetry will affect the health of the body. <>

The internal development of the human body is invisible to the naked eye, but it does not affect the aesthetics, as long as the body's functions are relatively healthy and normal, this is also possible. If the appearance is found to be asymmetrical, it will affect the serious life pattern, and it will also affect the discrimination of others, when the asymmetry is found, you should go to the hospital to check whether there is muscle atrophy or other diseases. The development of the human body is originally a lot of natural formations, and there is no way to explain it with science.

It is very normal for such a situation to occur, because there is nothing particularly symmetrical, just in the palm of our hand fingerprints are different.

It's possible that you're sick. The most common is that the poor standing and sitting posture for a long time makes the muscles compensate, and the original symmetrical human body is deformed, such as the size of the face, the size of the eyes, the tilt of the head and other symptoms.

This is very normal, because there are still asymmetrical places in the human body, such as some internal organs. Or some ribs or something.

It is very likely that there is a stroke, or there are other kinds of diseases in the body, which will also cause this asymmetry, if it is that subtle, in fact, it is only a genetic problem, and there is no other problem.

If there is some asymmetry, it may be a disease. If you encounter such a problem, you must go to the hospital for examination in time.

Because the structure of human beings is like this, some are symmetrical, some are asymmetrical, so this is a natural phenomenon.

It may be a stroke, because there is usually an asymmetry in the noon wind, and the pumping is very strong, which looks very obvious.

It may be due to a large amount of cold wind blowing, so there is a stroke, which can cause some parts of the body to be crooked.

It means that there is an underlying disease or inflammation on the body, so it is important to check and seek medical attention in time.

It means that there is a disease on the body, and if there is such a situation, you must seek medical attention in time and go to the hospital for examination.

This is the result of natural selection after a long period of evolution, and it is related to the evolutionary process of animals. The first animals were irregularly shaped, such as sponges, which existed on Earth 600 million years ago.

Sponges are multicellular animals with irregular shapes.

Sponges are the most primitive multicellular animals on Earth and can be said to be the ancestors of all animals. However, the shape of sponges is irregular, asymmetrical, and difficult to maintain balance, so although they belong to animals, they cannot move their bodies, and they can only rely on simple filtering of seawater for predation. Later, in order to facilitate mobile predation, animals gradually evolved a radially symmetrical body type, this symmetrical way has a central point, as long as you pass through this central point, you will get almost identical two parts from any part, the most typical animal is the starfish.

Starfish are typically radially symmetrical animals.

Radiation symmetry can be moved, but there are only a limited number of ways to do so, either by immobilizing the body, drifting with the current, or moving underwater, all of which are passive.

In order to change from passive to active, better adapt to changes in the environment, better prey and survive, and finally under the action of natural selection, the symmetrical animals on both sides evolved, that is, most of the animals and humans we see in our lives.

Beetles symmetrical on both sides.

Therefore, symmetry on both sides is convenient for maintaining balance, and there are various ways of movement that can be adopted, which is the reason for human symmetry.

The above content refers to Milley's children's book "A Brief History of Life".

Not perfectly symmetrical, you can see both sides of the face, both ears, eyes, hands are not perfectly symmetrical.

On the one hand, it is the reason for eating and chewing, which leads to the asymmetry of the left and right masseter muscles. On the one hand, there is the reason for sleeping, which is caused by the pressure of the face and the gravitational pull of the earth, which can lead to the asymmetry of the left and right faces.

Because of the influence of genes, people's facial bones are not completely symmetrical.

Because, in life, you may encounter some unexpected situations that cause the left and right sides to be not completely symmetrical. It also has something to do with people's bad habits. It is also very likely that it is due to stunted growth, etc.

The symmetry of the human body belongs to left-right symmetry. Because the appearance of both sides of the human body is the same, but the top and bottom are different, it can be called left and right symmetry. The general review and you also have symmetry up and down, symmetry inside and outside, which need to be classified according to different objects, and the human body belongs to the left and right symmetry.

Of course, if you observe the hand from a strict point of view, the human body is actually not 100% symmetrical, because there are still differences in the shape of external organs, and Suo Peiming is not 100% symmetrical in a sense, but can only be said to belong to the category of left and right symmetry.

In fact, the human body is basically asymmetrical.

At first glance, the left and right sides seem to be exactly the same, and this side is like a shadow on the other side.

But in fact, the left and right sides of the human body are not absolutely symmetrical. Not to mention that the eyes that look exactly the same on the surface, the left and right sides are not necessarily the same size, let's just say that the left and right arms and legs of a person are always of different thickness. People who often use their left arm or left leg, the left leg and the left arm are always thicker than the right one; It is almost common sense that people who often use the right side are thicker on the right side.

If you look at the internal organs of the human body, the difference between the left and right sides is even greater. There is a liver on the right side, but a spleen on the left; The left and right sides of the brain are also very different. The most obvious is the heart, which is not located in the middle of the body, therefore, the word "center" is not scientific.

The human heart is cut from the midline to the left of the middle of the chest, with only a small portion of the heart on the right side and the vast majority on the left.

The structure and function of the human brain are not exactly the same on the left and right sides, and for most people, the left side of the brain has the nerve center that manages speech and makes language coherent, while the right side is different, it does not care about the coherence of language.

So, when the human body moves, is it impossible to walk in a straight line? Someone did an experiment in which a man was asked to walk in the wilderness in the dark, and the person walked for half a day before returning to the original starting point. Superstitious people say it's "a ghost hitting a wall."

In fact, there was no ghost, but because the left and right legs were not of ordinary thickness and could not walk in a straight line, they took a detour and finally returned to the original starting point. However, when walking during the day, you can adjust the direction of travel from time to time with the help of your eyes, so you will not take a detour.

About the symmetry of the human body.

I feel that the side that is constantly strained should develop stronger than the other.

No, for example, the heart is on the left.

As long as it is complete, it is symmetrical.