Humans sit firmly at the top of the food chain pyramid. Do they have natural enemies on Earth? Who are they?

Humans have been the kings of the earth for tens of thousands of years. With the development of modern technology, human power is getting bigger and bigger, and the earth can hardly hold it. So what are the natural enemies of humans? Today we will discuss this issue.

Every animal has its natural enemy. Humans are animals, and of course they are no exception. In the biological world, humans seem to have long been at the top of the food chain. Humans came from ancient times, from apes to humans, becoming stronger and stronger, and finally becoming invincible and the master of the earth. The reason why humans are at the top of the food chain is not because of how strong or powerful individual humans are. If we talk about this, humans cannot beat elephants, lions, tigers, or even wolves and dogs.

The invincibility of human beings is intelligence. With intelligence, language and logical thinking, human beings can unite to fight against the enemy together, and can also create advanced tools, so that they can stand at the top of the food chain pyramid and look down on everything. But is there really nothing that human beings can restrain? No, it is too early.

Children in some places like to play a poker game called fishing. The rules are very simple. Divide the cards into two or more parts. Each person plays one card at a time. The big card eats the small card. Whoever has all his cards eaten loses. They put the poker cards in order from 3 to 13 (11~13 is J, Q, K). Above K is 2 and the big and small jokers. In this way, 3 is the smallest card and anyone can eat it, but 3 has a privilege, which is to eat the big and small jokers. This ace is like a human being. Although it is the largest, it will be eaten by the small 3. However, this small 3 is not the same as the small three. Everyone should distinguish them clearly.

Although this is a children's game, it illustrates a great truth, that is, nothing in this world is invincible. This is the principle of the mutual generation and mutual restraint of all things in the world, which contains the dialectics of the harmony of yin and yang and the opposite of things when they reach their extremes.

Everything has a weak spot, which is called a weak spot in martial arts. In martial arts novels, no matter how high a martial arts master is, he may be covered in a golden bell or iron cloth shirt, and he may not be afraid of being hit from head to toe, but everyone has a weak spot, which is a weak spot. If you hit his weak spot (soft spot), he will be dead.

So where is the weakness of human beings? It is also a small thing, too small to be seen by the naked eye, and even by a high-power optical microscope. Only an electron microscope can see it - the virus.

This new coronavirus has ravaged the world, infecting more than 40 million people and killing more than 1 million people so far. Although the casualties are smaller than those in World War I and World War II, no other modern war of mankind seems to have caused more casualties than this, which shows how powerful a tiny virus is.

Why are viruses so powerful? First, they are too small; second, there are too many of them; third, they are changeable; fourth, they are difficult to kill; and fifth, their origins remain a mystery.

Viruses are so small that they are hard to grasp. Since viruses are so small that they cannot be seen under a microscope, they were not known to humans until the end of the 19th century, but they are still invisible. In 1892, when a Russian plant physiologist was studying tobacco mosaic disease, he found that the juice of diseased tobacco leaves was filtered to remove bacteria, and then rubbed on healthy leaves, which still caused disease. So he believed that there was a microorganism smaller than bacteria, and it was this tiny thing that infected the tobacco leaves.

Although it was impossible to see such a small thing at that time, people still imagined that this invisible pathogen was called a "virus", also known as a "filterable virus". At that time, people had discovered bacteria through a microscope for more than 100 years. Viruses are so small that they can parasitize in bacteria and rely on the bacteria's cell body for nutrition and reproduction, so viruses are also called bacteriophages.

Because viruses are so small, it was not until the invention of the electron microscope in the 1930s that people could see the vague appearance of viruses through electron microscopes. It turns out that viruses are only tens to 100nm (nanometers), and the largest is only 300nm. 1m (meter) = 1000mm (millimeter), 1mm = 1000μm (micrometer), 1μm = 1000nm, so everyone can more intuitively understand how small viruses are, right?

There are so many viruses that they are too numerous to count. Viruses are everywhere in the world. There are millions of known viruses, and countless more have not yet been discovered. New viruses are being created all the time, so some people estimate that there may be more than 100 million types of viruses.

Among them, there are more than 1.7 million parasitic viruses in vertebrates, invertebrates, plants, mosses, mushrooms, brown algae, etc., 320,000 viruses with mammals as hosts, and thousands of viruses with humans as hosts. In this world, whether it is a beautiful flower, a mighty lion, a towering tree, or a reptile in the soil, it is inevitable to become a victim of the virus.

The most troubling thing is the changeable face of the virus. We can see from the SARS virus and the new coronavirus that when people have not yet figured out their toxicity at a certain stage, they will mutate again, making it difficult for people to guard against them. Why is it that the flu vaccine has been invented and widely used among the people for a long time, but the flu still spreads in waves every year? This is because there are many types of influenza viruses, including influenza A, influenza B, influenza C, etc., HIN1, H5N1, H7N9, etc., as well as human influenza, bird influenza, swine influenza, equine influenza, cattle influenza, etc. Generally, humans and other animals do not cross-infect, but swine influenza is an exception.

The transmission of viruses between hosts often changes. For example, the intermediate host of the new coronavirus has not yet been figured out. It is generally believed that the original host of this virus is bats, but bats cannot directly infect humans. It must pass through intermediate hosts to mutate into a virus strain that humans are sensitive to, and eventually become a terrible disaster for mankind. But the intermediate host will also change. This year it may be a pangolin, but next year it may be a snake, rat, or turtle.

Humans are overwhelmed by the attack of viruses. Virus diseases are difficult to treat because it is difficult to develop specific drugs. Viruses do not have the ability to survive. They live in host cells and rely on absorbing cell nutrients to reproduce. If you cut off the nutrition of the virus and kill it, it will damage healthy cells. Such drugs are difficult to study. Therefore, basically, the treatment of viral infections is to enhance the patient's own immunity and rely on the patient's immune system to fight the virus at the microscopic level. Killing a thousand people will hurt eight hundred of your own, so it is difficult to determine who will win in the battle. Many people's immune systems collapse in the fight against the virus, and eventually the virus kills important organs of the human body, causing the patient to fail and die.

Therefore, the most important means to deal with viral infection is epidemic prevention. In addition to anti-infection measures such as disinfection and isolation, the key and decisive role is the invention of antiviral vaccines. Since the advent of vaccines, the spread of some viral "plagues" that seriously endanger human survival, such as measles, smallpox, etc., has been effectively eradicated.

The mechanism of action of antiviral vaccines is actually to stimulate the body's own resistance. The main method is to inactivate or weaken the virus, and then inoculate it into the human body, causing people to be infected with mild symptoms, giving the human immune system a warning or reminder. After receiving the warning, the human body will activate the immune mechanism to resist these viruses. Through the fight with the virus, it knows the virus's weaknesses, and thus produces more fighters to fight these viruses, that is, antibodies.

In this way, the human body has gone through a simulated exercise and built a strong defense wall. When real viruses invade, we can be sure to block them from entering the country or destroy them. However, because viruses are very "smart", after coming into contact with human weapons to deal with them, they will "develop" new armor or weapons. This is the mutation of the virus, which makes people's epidemic prevention system ineffective. Therefore, viral infections are difficult to prevent and treat.

Where exactly the virus comes from is still a mystery. Biology has three domains and four kingdoms, namely the bacterial domain, archaea domain, and eukaryotic domain; the protist kingdom, the fungal kingdom, the plant kingdom, and the animal kingdom. Viruses jump out of the three domains and four kingdoms and belong to a world that is not controlled by gods, ghosts, or humans. We all know from watching fantasy movies that the demons outside the three realms are the most terrifying and the most difficult to deal with.

A virus is such a thing that is both dead and alive, so it is both a living thing and not a living thing. When it is in the cells of the host, it becomes a living parasite. When it leaves the host cell, it becomes an incomplete thing and cannot survive on its own.

What is a host? It is a biological cell that provides food and lodging for these viruses, not only for free, but also at the cost of its own life. In front of these tiny invisible things, the host is a hapless wimp.

Since people knew that viruses exist in this world, they have been trying to fight them. But so far, it is still unclear where these living and dead things come from and where their source is. They seem to exist everywhere, but they only have a piece of DNA or RNA, just like a person's broken limbs, dormant anywhere, not eating or moving, and without any signs of life. Once they find a breakthrough in living things, they will show their fangs and claws.

Some people believe that they are actually fragments of life, genes abandoned by dead life, excrement of life, and disabled life forms. But where they came from and why they desperately need to find a host to revive are still not fully understood, and perhaps they will never be understood.

Are these viruses like the three in a deck of cards, designed to deal with the big and small jokers? Are they natural enemies set up by nature to curb the greedy plunder of human beings? Will humans eventually be destroyed by viruses? No one can say for sure.

But in addition to viruses, there are many disasters that can kill humans and cannot be dealt with, such as huge celestial events, geological and climate disasters on the earth itself, solar drastic changes, etc. These are not the topics to be discussed today and will be discussed next time.

That’s it, welcome to discuss, thanks for reading.

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