Do you know what is the rudiment of a person? Part of the organs in our body is an indisputable proof of evolution. These structures have long lost their significance, but their presence suggests that there is a genetic link between representatives of various systematic units.
Human rudimentary organs
Translated from Latin, this term means "beginning". Indeed, rudiments are underdeveloped organs that are laid back in the period of intrauterine development. In an adult, they lose their meaning. But among the ancestors of modern species, rudiments performed important functions. Many animals have such structures. For example, in whales, the hind limbs are hidden in the body, because they are absolutely not needed for movement in the water. But their rudiments still remained.
How to determine which trait of a person is not a rudiment? This is an organ that has not lost its importance compared to its ancestors. So, in the digestive system, all parts provide the breakdown of nutrients. In addition to the appendix, the removal of which does not have a significant effect on the vital activity of the body.
Another evidence of evolution is atavisms - signs of ancestors that appear in modern species. Their example is the development of a continuous hairline or several pairs of mammary glands. In contrast to the rudiments that all representatives of the species have, atavisms rarely develop. Their development indicates a violation of the individual development of organisms.
The rudiments of a person are ...
The presence of a tail can not be called a sign of a person. However, before the fourth week of fetal development, it is actively developing. In this period, the embryos of humans and vertebrates are similar. With further normal development, its development does not occur. The appearance of a tailed man is atavism.
The human spine consists of five sections. The lowermost one is called the tailbone - this is the vestigial tail. It is formed by several vertebrae that are fused together. It is his presence that indicates the kinship of man and monkeys.
It is worth saying that many rudimentary organs still perform certain functions in the body. For example, muscles and ligaments are attached to the coccyx, which ensure the activity of the genitourinary system. In addition, it is this part of the spine that provides the correct distribution of physical activity on the pelvis and is the main point of support for body tilts.
Wisdom teeth
An example of a human rudiment is the eighth teeth in each row. They are cut not in childhood, but at the age of 18 to 25 years. Therefore, they are traditionally called wisdom teeth. 10% of people do not have them at all.
As a rule, they give a person a lot of trouble. Since they are not preceded by dairy, the process of cutting them is very painful. Typically, these teeth have 4-5 roots, which sometimes grow together. And the crown itself is significant, so it often does not have enough space. Eights practically do not participate in the process of food grinding, therefore, self-cleaning processes "do not work" with them. The result is inevitable destruction and removal. But if you are lucky and they develop normally, then such teeth are an excellent basis for prostheses.
But our ancestors needed such teeth to grind hard and unprocessed food. And their jaw size was much larger, so there was enough space for cutting eights.
Appendix
The vermiform appendix of the colon in humans is a sign that is a vestigial. Its length is only 10 cm. The appendix was inherited from herbivores. They have the length of this process reaches several meters. In animals, the appendix secretes the enzymes necessary for the breakdown of nutrients, and is simply necessary for the digestion of roughage.
In the human body, this process does not play such an important role. However, the appendix contains lymphoid formations, therefore, performs a protective function. It also secretes lipase and amylase enzymes and hormones that regulate intestinal motility.
Third eyelid
Another vestigial in humans is the blinking membrane, which is located in the inner corner of the eyes. The third eyelid is also called a lunar fold. In birds and some reptiles, it is fully developed, like the upper eyelid of a person. In this case, the third eyelid performs the function of protecting and moisturizing the eyes.
In humans, the third-century rudiment directs mucus, which collects dust and dirt, into the tear duct. Then they are removed from the eye.
Ear muscles
The outer ear of a person also has its own differences compared with the ancestors. Animals must constantly listen in anticipation of danger or impending prey. Therefore, their auricle has a pointed shape, and the muscles provide movement.
In everyday life, such structural features are unlikely to be useful. Therefore, the outer ear has a rounded shape, and the ear muscles are underdeveloped. This is a typical example of rudiments. Although sometimes there are people who know how to move their ears.
Palmar muscle
According to statistics, this rudiment is absent in 15% of the world's population. How to check if you enter this number? The most effective is the Thomson method. To do this, squeeze four fingers into a fist, covering them with a large one, and slightly bend the brush. Did you see a tendon on your wrist? So, you are the owner of a long palmar muscle, which is a rudiment in humans . Animals with her help release claws. This is necessary for hunting and strengthening the grip when jumping from support to support.
Pyramidal muscle
In the abdomen is a muscle, which is also a rudiment in humans. It has the appearance of a small triangle, therefore it is called pyramidal. This muscle is small. In humans, she stretches the white line of the abdomen. So called the fibrous structure of the anterior abdominal wall, horizontally located in the midline. Visually, it really looks like a line, and the color is due to the presence of collagen. In some people, the pyramidal muscle does not form. Such a structure is fully developed in marsupial mammals. In these animals, the pyramidal muscle is located around the bag in which the cub develops. Like a long palmar muscle, this rudiment is not found in all people.
Goose-flesh
When a person experiences strong emotions or feels cold, small pimples appear on the skin at the base of the hair follicles. This is a manifestation of the pilomotor reflex. At the same time, the muscles that are at the base of the follicles raise hair. Such a process is called piloerection.
In humans, the pilomotor reflex is rudimentary. The fact is that in mammals, raised hairs provided a delay at the skin surface of the layer of air heated by the body. And in a dangerous situation, an animal with a raised coat looks more intimidating. Since the human hairline is developed only in certain parts of the body, piloerection is not of great practical importance.
Racial features
It is known that some rudimentary signs are characteristic only for people of certain races. For example, representatives of the Mongoloids have an epicanthus. This is the name for the vertical skin fold located at the inner corner of the eye. She completely or partially covers the lacrimal tubercle. It is believed that in ancient times, such a "Mongol fold" protected the eyes from harsh weather conditions.
There is an assumption that steatopygia is also a rudiment. This is an accumulation of adipose tissue in the upper part of the buttocks. Its function is similar to a camel hump - a supply of nutrients.
Thus, the presence of a person's vestigial organs indicates his animal origin. Evolutionary changes took place in the direction of complicating the structure, ensuring the adaptation of the organism to various conditions of existence.