The human evolution has gone through several steps. In this essay, the focal point is on the gradual change of the heritable and biological traits of human organisms with emphasis on the difficulties they undergo within the environment. The evolutionary methods give rise to biodiversity at all tiers of human species. The focus is also on human viruses and how the physique immune system reacts to the pathogens.
In human evolution, the new groups emerge in response to the desires of the difficult physical, economic and social surroundings. At this juncture, the need for food is cosy by literally gathering the uncommon or limited food commodities. At some point, looking becomes a source of obtaining food items for the people. The human society, therefore, is determined by the levels of political and sexual/biological relations they engage in. The modern human evolution is also ratified by the rapid development of language and culture which is said to have transformed humankind to its states presently. The scientific study of human development is known as paleoanthropology, and it involves analysis of human biological make up, cultural traits, and society. Through the field, it is possible for scientists make appropriate comparison between humans and other species. Here, the emphasis is made on the genes, behavior, body forms and the physiological make up. The scientists can also understand how limitations and potentials of people have changed over time due to evolution. Paleoanthropology also focuses on investigating the scientific origin of the defining traits of people, over millions of years ago. Early human fossils, offers the most reliable clues about the human ancient past. Evidences such as bones, pottery, skulls, tools, footprints, butchery marks on animal bones, tools, weapons, clothing, ornaments, settlements among others. Some of the remains were buried and preserved naturally but were later exposed to the ground surface by rain, floods, rivers, wind, digging or soil erosion. Through the study of the bone fossils, scientists can understand human physical appearance and how such traits have transformed over time. The fossilized bones are of various sizes, shapes, and markings that are believed to be left by muscles. Through close examination of the bones, the scientists can detect how the brains size of early humans have changed over time. Also, by studying the archeological shreds of evidence, the scientists can understand how early human beings made and utilized their tools. It is also possible to recognize the kind settlements that people lived in in the past. How their lifestyles have changed over time is a clear indication of the gradual human evolution, and this depends fully on the type of archeological evidence at stake.
All human beings and other species originated through biological evolution (Relethford, 2008). The process of evolution analyzes the various changes that species undergoes through before their extinct or death. For instance, human beings can reproduce sexually resulting in fertile offspring. Upon maturation, the offspring too can breed and give birth to other productive humans. In this system, the scientists classify the modern human system as Homo sapiens. The surviving of the offspring depends on a lot of factors, parental care being the primary factor. Other factors include things such as environmental conditions (weather and climate), diseases, nutritional values administered to the young ones, culture, and beliefs of the people.
The evolution process also occurs as a result of the changes in the genetic make-up of the organisms which determines the particular characteristics of the species. Genes constitute the DNA information that is significant to the overall growth and development of an individual. DNA is a chemical molecule that is inherited specifically from the parents. The molecular expressions of the DNA gene embedded in the population connected to hereditary and kinship. It is present in all nucleus cells of human beings, and it determines their appearance and how they respond to specific occurrences in the environment. The information in the DNA can be altered through the process of mutation (Plyusnin et al, 1996). Genes influences the behavior and of the body over time. Therefore, the characteristics one inherits genetically would ascertain the chances of the organism to survive or reproduce. Evolution alters the genetically acquired ways of growing and developing that characterizes a given populace (individuals of the same species occupying a given habitat). Offspring inherit the adaptive genetic components from their parents. The changes are than replicated in the entire population. Such changes enhance the ability of the offspring to survive and for conception. Changes in the environment may change the genetic make-up of the human species, and this can alter overall ways of life of the species, for instance, what they consume as food, where they live and how they grow. Human evolution takes place since the new variations in the early ancestors facilitates new capabilities to adapt to fluctuations in the environmental conditions, and so transformed the way of life of the humans (Balter, 2005). Other factors that show humans are evolving includes, human brains are still shrinking, the persistent resistance to diseases which is as a result of body cell mutations, human fertility rates which determine their ability to give birth to more offspring (Stock, 2008). Upon reaching the environment, their chances of survival are determined by natural selection. In this case, once survival depends on their ability to resist diseases and how they respond to treatments.
The Role of Viruses in Human Evolution.
Viruses are said to be the major drivers of human evolution, that is, the constant battles between the viruses and the host (humans) all along is what biologists believe that is a major driving force of evolution (Van Blerkom, 2003). Animal viruses are classified into various families depending on the viral genome i.e. DNA or RNA. The adaptive patterns caused by the viruses are too much strong and clear. The adaptations mainly occur in proteins which primarily interacts with the viruses. Proteins consist of essential nutrients necessary for the body of mammals. The nutrients are crucial to a vast array of functions that is responsible for the cells’ functioning. Recent studies reveal that certain variations in the size, shape, composition of proteins are what have assisted human beings and other mammals to respond to viruses. The revelation is what has helped scientists to come up with the new therapeutic leads to conquer or take control of the threats that results from virus attack. Like any other pathogens, the virus is a disease-causing germ. The body should have defensive mechanisms to respond to any threat that occurs as a result of the virus invasion. The viruses alter the functions of the body cells and organs. Presumably, certain parts of the cells have been used in the fight against viruses, and this is done without causing detrimental threats to the organs’ functionality.
When the virus hijacks the body, proteins react to enhance the needed immunity against the threat that may be due to the disease (Feschotte & Gilbert, 2012). The immune system, therefore, assists the body to adapt. Therefore, viruses have affected the humans in almost all aspects of their lives. The availability of proteins in the body makes essential cellular functions possible. Hence the scientists can use the analogy to be able to enact ways or cures to face future threats by the virus. Whenever a pandemic or epidemic strike, the humans must be able to develop the means to adapt to such conditions. Failure to which implies that their chances of survival diminish. Hence, they risk becoming extinct. It is, therefore, the duty of the health practitioners and scientists to apply the visible changes in protein to establish new ways that would help the body adapt. Through this knowledge, the scientists are in a position to explain why similar species evolve completely different methods in performing the same cellular functions like DNA duplication or creation of cell membrane (Deininger et al, 2003). Therefore, viruses are believed to be withholding vital information concerning how humans have evolved over time.
When the virus invades the body, it hijacks nearly all the functions of the host human cells. After that, the virus can replicate and spread to the majority of the parts of the body cells and organs (Plyusnin et al, 1996). This suggests that viruses are responsible drivers of the human cellular evolution. Because it stays within the body, the virus is believed to have more impact on the human evolution than other evolutionary pressures such as environmental conditions, socialization or tradition, and cultural beliefs. Virus invasion into the body has been a cause of some biological mysteries such as the following: closely related species evolving different machinery to perform same cellular functions, production of membranes or replications of the DNA (Van Blerkom, 2003). Human beings have involved in constant wars with the virus, for instance, the Human Immune Deficiency Virus which severely harms the body. The HIV is what causes AIDS, and once it enters the body, it multiplies rapidly and can result in the death of the victims. AIDS is one of the leader killers of people living on earth. Some believe it is a curse, but it is a product of viral infection of the body. Considering such effects, the humans have engaged in constant battles with the virus to control its spread or acquisition amongst different individuals. The insight is to help in the fighting of diseases today.
Unlike most of the viruses that infect, replicate, spread and later disappear away from the host, the retroviruses nudge their way into the genome of the host where they are copied and passed to daughter cells for the life of the hosts (Feschotte & Gilbert, 2012). The retrovirus cell is said to have sneaked its way into one of the sperm or egg cells of the human ancestors. The virus is, therefore, able to be passed on through subsequent generations. Hence, the finding that the host and virus have become one and the same thing. This goes by the saying that without the retroviruses, humans might have never evolved their placentas, and this means humans would be extinct by now. The viral DNA uses its genes to replicate itself into the host’s genome. The copies spread in different parts of the body at a different point in time. Such symbiotic relationship between the virus and the host is what constitute raw materials for developing new body functions (Stock, 2008).
Therefore, if humans or other mammals lived millions of years ago, the symbiotic relationships between them and the retroviruses is what enabled them to evolve a placenta over the years and the upcoming generations. For the fetus to get mature in the mother’s womb/uterus, the human enacts certain ways to get oxygen and specific nutrients (Deininger et al, 2003). The animal also would remove wastes and keep blood supplies separate. The early animals had a way of sparing the viral parts left in the junk drawers of the genome and utilize the viral gene to produce a placenta. The process, together with other symbiotic viruses is what transform the ball cells into a fully formed squalling newborn. It also protects the infants from pathogens. Junk DNA is a portion of the symbiotic viruses that is a significant catalyst in the evolution of new species. Therefore, the evolution of pregnancy through the placenta is considered a clear evidence that the viruses occupying the human genome are responsible for the rise in new species. Hence, the role of the endogenous retroviruses in human evolution implies that the DNA diminishes the boundary between humans and virus. In other words, human and virus are part of each other.
Thousands of viruses are embedded in the human genomes, and each of them has got potential effects (Van Blerkom, 2003). According to Cedric Feschottea, Geneticist at the University of Utah, viruses take a crucial role enhancing evolution of the mammalian immune system. According to him, the viruses are equipped with specified weapons that are destined to evade the human immune system. For instance, Mer41, a virus that infiltrated the genome forty- five to sixty million years ago, controls one of the proteins in humans, and this also has an effect on the human immune system. Due to the human vulnerability to infectious diseases, there is need to improve ones’ ability to survive the pathogens. Such protection can be derived from viruses, and this has an influence in the evolutionary process of human beings. Therefore, endogenous viruses have had impacts on human evolution and still affects our ways of life. The retroviruses also have an influence on how people think as species. That there exists an intimate relationship between the virus and the human self, hence, through a constant exchange of useful DNA, humans have molded the perceptions about themselves as components of the DNA which are infiltrated by the viruses.
However, like any other pathogens, the effects of viruses on human are not always beneficial as they also result to infiltration of deadly diseases and infections into the body. For example, diseases like common cold, HIV/aids, chickenpox, herpes, human papillomavirus (HPV), Mumps, Measles, and Rubella, viral meningitis, viral pneumonia, viral gastroenteritis, Ebola and viral hepatitis (Plyusnin et al, 1996). The viral diseases are contagious hence can easily be spread from one person to the other, for instance, through engaging in sexual intercourse with a person infected with a virus transmitted sexually. Other ways include: eating contaminated food or drinks contaminated with a virus, breathing in air droplets from a person infected by a virus, indirect transmission e.g. through insects such as mosquitoes, tick, or mouse. Upon entering the body, the virus multiplies and occupy the entire body system. The viral diseases portray a variety of symptoms which vary depending on factors such as; type of viral infection, age, and overall ones’ health. The antibiotics only treat diseases caused by bacteria, hence cannot be applied in the treatment of a viral infection.
The common cold is the most common viral disease, and it is caused by the virus attacking the upper respiratory tract which is made up of the nose and the throat (Krug et al (2003). It is generally self-limiting on the healthy individuals. Therefore, it implies that the viral infection only increases illness for a particular period. After which, the body immune system responds by attacking the virus, the symptoms disappear and then the person recovers. In some cases, viral infections develop serious and life-threatening complications, for instance, pneumonia, dehydration or secondary bacterial infections. People who are most vulnerable to such complications possess certain symptoms like; weak or suppressed immune system and are usually the very young or old individuals. Some of them have chronic infections (Feschotte & Gilbert, 2012). Furthermore, some of the viral infections transmitted sexually are more dangerous and lead to death and sufferings. The reason is that they have no permanent cure. Such diseases include HIV/AIDS, EBOLA, and HPV. It is, therefore, advisable that one seeks immediate medical attention if he or she suspects having a viral disease or is exposed to any sexually transmitted infection.
According to Krug et al (2003), viruses are responsible for the taking of countless lives, for instance, the Hantavirus comprises multiple viruses that can result in lung diseases, fever or kidney infection. Others are like the Lass and bird flu which is usually transmitted by rodents, Marburg virus which constitutes 90% of mortality rate, Machupo virus which causes constant bleeding and high fever, Junin virus responsible for tissue inflammation, Kyasunur forest virus causing muscle pain, high fever and bleeding. Apart from the above examples is Dengue fever which is spread by mosquito and boast extremely high rates of fatality. It affects between fifty to hundred million people annually. It is also a famous disease in most tourist’s destinations such as Thailand, Philippines, and India. Consequently, there exists the Ebola virus which is also very deadly and has resulted in thousands of deaths in the West Africa and beyond.
To treat the viral infections, it is vital that the scientists try their best in addressing the specific complications and symptoms of the diseases (Münz et al, 2009). For instance, the spread of Ebola virus is controlled by maintaining oxygen levels, treating every infection that arises, providing fluids as well as keeping stable the electrolyte levels. Above all, maintaining the blood pressure level would be a meaningful remedy. For other viruses, the scientists are currently engaged in continuous research to develop appropriate vaccines that would help in keeping them at bay. Enhancing the protein adaptations while responding to the particular symptoms would also be a necessary move for the scientists. Nevertheless, in this highly mobile world, the development of the international trade, as well as the presence of millions of people traveling through the air at any moment, has given the viruses more opportunities to spread and disseminate globally. The growth in human mobility across the world has connected pathogens e.g. bacteria, fungi, and viruses to new and growing hosts of the population thus contribute to the emergence and reemergence of disease epidemics.
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