Do you know what is a rudiment in humans? Part of the organs in our body is 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.
Rudimentary human organs
In Latin, this term means "beginning". Indeed, the rudiments are underdeveloped organs that are laid down during the period of intrauterine development. In an adult organism, they lose their significance. But in the ancestors of modern species, the 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 the beginnings of them still remained.
How to determine which feature 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 partsprovide the breakdown of nutrients. Except for the appendix, the removal of which does not have a significant effect on the vital activity of the body.
Another proof of evolution are atavisms - signs of ancestors that appear in modern species. Their example is the development of a continuous hairline or several pairs of mammary glands. Unlike the rudiments that all representatives of the species have, atavisms develop quite rarely. Their development indicates a violation of the individual development of organisms.
The rudiments in humans are…
The presence of a tail is by no means a sign of a person. However, until the fourth week of intrauterine development, it is actively developing. During this period, the embryos of humans and vertebrates are similar. With further normal development, its development does not occur. The birth of a tailed man is an atavism.
The human spine consists of five sections. The lowest is called the coccyx - this is the rudimentary tail. It is formed by several vertebrae that are fused together. It is its presence that indicates the relationship between humans and monkeys.
It is worth saying that many vestigial 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 section of the spine that ensures the correct distribution of physical load on the pelvis and is the main fulcrum when tilting the body.
Wisdom teeth
An example of a human rudiment is the eighth teeth in each row. They erupt not in childhood, but at the age of 18 to 25 years. Therefore, they are traditionally called wisdom teeth. 10% of people don't 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. Usually such teeth have 4-5 roots, which sometimes grow together. And the crown itself is of considerable size, so it often does not have enough space. Eights practically do not participate in the process of grinding food, 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 dentures.
But our ancestors needed such teeth to grind hard and unprocessed food. And their jaws were much larger, so there was enough room to cut eights.
Appendix
The vermiform appendix of the large intestine in humans is a sign that is a rudiment. Its length is only 10 cm. We inherited the appendix from herbivores. Their length of this process reaches several meters. In animals, the appendix secretes the enzymes necessary for the breakdown of nutrients and is essential for the digestion of roughage.
In the human body, this process does not play such an important role. However, the appendix contains lymphoid masses,therefore it performs a protective function. It also secretes the enzymes lipase and amylase and hormones that regulate intestinal motility.
Third eyelid
Another rudiment in humans is the nictitating membrane, which is located in the inner corner of the eyes. The third eyelid is also called the lunate 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 rudiment of the third eyelid directs mucus, which collects dust and dirt, into the tear duct. Then they are removed from the eye.
Ear muscles
The outer ear in humans also has its own differences compared to the ancestors. Animals need to constantly listen in anticipation of danger or approaching 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 can move their ears.
Long palmar muscle
According to statistics, this rudiment is absent in 15% of the world's population. How to check if you are in this number? The most effective is the Thomson method. To do this, you need to squeeze four fingers into a fist, covering them with a thumb, and a littlebend the brush. See the tendon on the wrist? So, you are the owner of a long palmar muscle, which in humans is a rudiment. Animals use it to release their 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 looks like a small triangle, therefore it is called pyramidal. This muscle is small. In humans, it stretches the white line of the abdomen. This is the name of the fibrous structure of the anterior abdominal wall, horizontally located along 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. This structure is fully developed in marsupial mammals. In these animals, the pyramidal muscle is located around the sac in which the young develop. Like the long palmar muscle, this rudiment is not found in all people.
Goosebumps
When a person experiences strong emotions or feels cold, small bumps appear on the skin at the base of the hair follicles. This is a manifestation of the pilomotor reflex. In this case, the muscles that are at the base of the follicles raise the hair. This process is called piloerection.
In humans, the pilomotor reflex is rudimentary. The fact is that in mammals, raised hairs ensured a delay at the surface of the skin of a layer of air heatedbody. And in a dangerous situation, an animal with raised hair looks more intimidating. Since human hair is developed only in certain areas of the body, piloerection is of no practical importance.
Racial Features
It is known that certain rudimentary features are characteristic only for people of certain races. For example, representatives of the Mongoloids have epicanthus. This is the name given to the vertical skin fold located at the inner corner of the eye. It completely or partially covers the lacrimal tubercle. It is believed that in ancient times, such a "Mongolian fold" protected the eyes from harsh weather conditions.
There is an assumption that steatopygia is also a rudiment. This is an accumulation of fatty tissue in the upper part of the buttocks. Its function is similar to that of a camel's hump - a supply of nutrients.
Thus, the presence of rudimentary organs in humans indicates its animal origin. Evolutionary changes took place in the direction of complication of the structure, ensuring the adaptation of the organism to various conditions of existence.
