The virus has certain life characteristics under certain conditions, but it cannot complete any life process by itself. They can't metabolize nutrients, can't produce energy, and can't be used as food for other creatures. For viruses themselves, the only purpose of their existence is to infect the host, and then use the resources of the host cell to continuously expand their number, which is a group of "lazy" parasites. However, we must not ignore their existence. Because these "lazy" parasites play an extremely important role in nature. They are the promoters of life evolution and the supporters of the normal operation of the whole ecosystem.
In the "ocean" of viruses, human beings can stay healthy because we have a perfect defense system to constantly monitor and remove pathogens such as invasive viruses. If something goes wrong with this system, the human body will become fragile. This defense system is the immune system. Human immunodeficiency virus (HIV) will destroy the immune system after infecting human body. After the collapse of the immune system, any common infection will cause fatal harm to the human body. Therefore, the danger of AIDS lies not in the HIV itself, but in the complications caused by various opportunistic infections after HIV infection. In the initial stage of the origin of life, the immune system has not been established and perfected. The evolution of the immune system is an important basis for the evolution of the whole life system, and the evolution of the immune system is completed under the stimulation of various pathogens such as viruses.
With the development of modern sequencing technology, the human genome has been deciphered. Scientists are surprised to find that there are as many as 654.38+ 10,000 fragments in the human genome, accounting for 8% of the human genome, while the sequences encoding all protein of human cells only account for 654.38+0.2%-654.38+0.5% of the genome. Such a large number of viral gene fragments may also play an important role in the human genome. Although there are still many unknown things to be explored, there is no doubt that without these viral gene fragments, human cells cannot work normally.
Viruses also play an important role in the balance of ecosystems. In the ocean, there are about 10 cubic meters of virus infection every second, which is one of the main causes of marine life death. No matter shrimp or whale, it is difficult to escape the attack of virus, and the contents released after their death will become food for other creatures. In addition to animals and plants, bacteria are also important targets of virus infection. It is estimated that viruses kill almost half of the bacteria in the ocean every day and release billions of tons of carbon for other organisms, which is also an important part of the natural carbon cycle. Therefore, if there is no virus in the ocean, there will be a lack of an important chain in the material cycle, and it will be difficult for many lives to get opportunities for growth and reproduction.
In addition, there are a large number of dinoflagellates living in the ocean, which bear about14 of photosynthesis on the earth and produce a lot of oxygen for the earth. Scientists found that in this algae, some genes encoding protein of photosynthesis came from viruses. According to scientists' estimation, 10% of photosynthesis on the earth is related to protein encoded by virus genes. In addition, algae and bacteria on earth play an important role in maintaining the balance of gases such as oxygen and carbon dioxide in the earth's atmosphere. By controlling their numbers, viruses also indirectly affect the climate.
For ourselves, the role of viruses cannot be underestimated. There are more than 10000000000000 bacteria living in our intestines, which constitute the intestinal flora that people often say. These bacteria are very important to human health. They not only help people digest food, participate in energy metabolism, but also affect the function of human immune system. Studies have shown that there are more viruses than bacteria in human intestines, and they may have direct beneficial effects besides helping people control the balance of intestinal flora. For example, recent studies have found that norovirus in the intestine of mice can help mice repair damaged intestinal mucosa and maintain normal intestinal mucosal immune function. In addition, some mild viruses, such as rhinovirus, can also exercise our immune system not to respond to minor stimuli, thus reducing allergic reactions.
We have been living in a virus. They bring diseases and help sustain life. With the deepening of research, I believe we will have a deeper understanding of the virus.