Modern Human Anatomy Free Essay

Modern Human Anatomy

Human Hearing System

The inner ear as an organ of hearing and balance has emerged in the first vertebrates, and since then has undergone many improvements in the process of evolution. In addition, it was gradually complemented by the middle (the amphibians and reptiles) and the outer ear, available in mammals. The inner ear has developed to maintain the sense of balance and has the system of round and oval sacs, as well as semicircular canals. The amount of the latter gradually increased, reaching three in mammals. Moreover, in the course of evolution, there have been significant changes in the structure of visceral skeleton, which eventually finished in the formation of auditory ossicles. Finally, the outer ear was formed as a receiver of sound waves, finalizing the evolution of the organs of hearing in mammals and, therefore, humans.

Human Vision System

The eyes have gradually developed from simple light-sensitive cells to the complex structures. In vertebrates, including humans, they incorporate lens, retina, and the other components. In addition, the skull of some species, including Homo, has the eye sockets located in front, within the same horizontal plane. As a result, the fields of the right and left eyes became combined. The further development of visual analyzer (cerebral cortex) allowed combining the images received by each eye into a single one, causing the emergence of stereoscopic vision. At the same time, the development of color vision in primates and Homo species was due to the transition to the daily lifestyle, which was provoked by the need for distinguishing ripe and unripe fruits, shades of green, and so on. Consequently, primates and, therefore, humans, lost some visual capabilities possessed by their ancestors that were active during the night but gained the new ones. The photoreceptors in their eyes, which were previously responsible for the perception of the ultraviolet rays, have evolved into the ones capable of perceiving colors (red, blue, and green), and after that the trichromatic vision has emerged.

Modern Human Brain

After the Homo species have become subject to energetic shift as a result of combining hunting and gathering, as well as food processing, their brain has become larger as less energy was spent on digestion. Moreover, the biggest contribution to its development was made by complex social relationships that became necessary due to the abandonment of the nocturnal lifestyle and life in groups. The complexity of such existence is largely determined by the formation of couples and monogamy that can ensure the survival in the long-term perspective. Besides, both of those factors place high demands on the brain – the careful choice of a partner and negotiations between the group members. In other words, the complexity and intensity of social relationships had a strong evolutionary effect on the development of a brain, guaranteeing the favorable conditions for the emergence of the system of values and culture (the so-called human spark) in the future.

Human Hand

Bipedalism gave the Homo species free upper limbs, which could be used for a variety of tasks, including gathering and processing of food and, most importantly, the manufacturing and use of tools. In turn, the hands have become subject to the following evolutional changes. The strong opposing thumb enabled a tight grip of large objects, and, in combination with another finger, made it possible to move smaller ones accurately. At once, the other fingers became shorter to make their movements more precise and hold small tools tightly while having a full control over them. The precision was also enhanced through the replacement of claws with nails that played a protective role, and the emergence of sensitive fingertips, which made it possible to identify the shape and size of different objects with ease. Thus, the evolution has transformed the hand into an indispensable tool of a human.

Human Locomotor Adaptation

The Homo species’ transition to the life on the ground due to the climate change and scarcity of food has reduced the need for climbing and has contributed to the development of bipedalism. Consecutively, their bodies have used to the changes, developing the wide hips, broad and flat chest, and massive bones of the lower limbs. The spine became a shock absorber due to the presence of natural curves which protected its discs and ligaments from the injury during running or jumping. Moreover, the need to shift weight from the heel to the front of the foot when walking made every step the balancing exercise. As a result the arced feet with short thumbs have emerged. Finally, the legs became longer and stronger to cover larger distances in search of food and shelter, as well as to pursue the prey during the hunt.

Human Skin

The human skin has also been subject to changes during the course of the evolution. In particular, the body hair of the humans’ ancestors has become scarce in comparison with that of the majority of land-dwelling mammals. On the one hand, fur provides an evolutionary advantage even in the hot climate as it protects from the sun. However, bipedalism reduced the daily dose of received solar radiation by about one-third due to the vertical stance. Moreover, during running, the furless body cooled better than the one with fur. These factors had their impact on the disappearance of the thick hair. Meanwhile, the ancient hominids have lost the protection it provided. In turn, their skin has become oilier with an abundance of sebaceous glands, layer of subcutaneous fat, and the developed network of blood vessels and sweat glands, protecting them from water, cold, and heat respectively. Moreover, the openness of the human skin to the impact of the sun rays has accelerated the development of melanocytes, which produced the pigments that reduced the negative effects of the ultraviolet radiation.

Human Spark

As it was mentioned before, the emergence of the complex social relations helped cause the further development of the human brain as a whole, as well as its certain parts. In this regard, it is possible to indicate the frontal lobe, which is responsible mainly for thinking, consciousness, and the communicative ability, contributing to the emergence of the so-called human spark. Successively, the appearance of decorations, as well as mystical and religious beliefs, has become possible, differentiating humans from all the other species. Moreover, the temporal lobe, which is primarily responsible for hearing, has also developed to recognize the speech and sounds, allowing a better coordination of the group activities, and influencing the emergence of such components of human culture as music and singing.

Adjustment of Behavioral Patterns

Given the fact that the current distinctive features of Homo sapiens have developed in the course of evolution as a response to certain changes in the life of the humans’ ancestors, there is a possibility that they may be lost in a similar way. However, it is possible to put the bodies and minds of the modern people in better accord with the evolutionary adaptations. This goal can be achieved through the adjustment of one’s lifestyle in the following ways.

First of all, it is possible to point out the primary consequence of bipedality – the posture – as a unique feature of Homo sapiens. It allows performing simple and complex movements and determines the state balance between skeletal and muscular systems that protects body structures from strain or injuries. However, the irregular body position quickly causes the deformations of spine, chest, pelvis, and lower limbs. For example, scoliosis and flatfoot are extreme manifestations of an incorrect posture. In turn, the position of body segments during a movement significantly affects the efficiency of motor activity. For instance, it is difficult to imagine a round-shouldered person moving efficiently as its actions tend to be clumsy and may end with an injury. Thus, it is important to maintain the correct posture through specific physical activity, which concentrates on the restoration of the muscular balance in the body. Hence, such exercises must be performed on a daily basis.

Simultaneously, in the course of evolution, the digestive system of the Homo species has undergone considerable changes, becoming adapted to processed food that is much easier to digest. As a result, it started consuming less energy. To control such an energetic shift, it is necessary for modern people to maintain a balanced diet and avoid overeating. In particular, it is recommended to monitor the amount of calories and limit the energy received from fats, preferring the unsaturated ones. One should also strive to increase the proportion of fruits, vegetables, whole grains, legumes and nuts in the daily diet, as well as decrease the intake of simple carbohydrates. As a result, the digestive system will not be subject to the excessive loads, meaning that the energy balance in the human body will remain stable.

Furthermore, the trichromatic vision of the Homo species has developed due to the transition from a nocturnal activity to the one during the daytime, causing the evolution of photoreceptors in the human eye. In turn, the modern people are incapable of seeing well and differentiating colors in darkness. Therefore, it is important to adhere to the specific daily regime, which provides enough time for the night rest, thus ensuring that the capabilities of the human vision system are used to their full extent. In this regard, it is possible to identify the importance of physical activity – in the case a person remains idle during the day, its period of wakefulness increases greatly. Moreover, these extra hours are counterproductive as it is difficult to engage one’s brain in any activity due to it being in the phase of rest. Thus, one’s day must be planned properly to ensure the lack of activity during the nighttime, when the trichromatic vision is of little importance.

Finally, the transition to processed food has contributed to the growth of human brain and emergence of complex behavioral patterns and, eventually, the development of culture and traditions, e.g. the so-called human spark. Therefore, one should pay enough attention to the socialization as the role of this process in the life of both society and individual is significant. In particular, it defines the ways, in which the person forms its culture values and norms of behavior through the collaboration with the partners. Also, it facilitates the realization of one’s abilities and development as a personality. Moreover, for the society as a whole, the socialization process becomes an assurance, defining the ability of the representatives of a new generation to take the place of the older one in social interactions and learn from their experience, skills, and values. In other words, socialization provides the renewal of public life. The lack of it does  not only give rise to conflicts of generations but also may cause the  disruption of social life, disintegration of society, loss of its culture, integrity, and, therefore, the human spark as a whole. Thus, it is necessary to avoid seclusion and maintain the productive contacts with the other people to ensure one’s development as a personality, which was initially facilitated by the life in a group.

By adjusting their lifestyle in the ways described above, the modern people can make their bodies and minds more harmonious with the evolutionary adaptations. In other words, the abilities and features developed by the Homo species in the course of evolution will continue to remain relevant. Eventually, these measures will ensure the long and healthy life of the mankind as a whole.

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