Natural selection and survival of the fittest are the basic laws of nature. How to choose the evolutionary path of any organism is made by nature according to this law.
In the animal world, there are carnivores and herbivores. Carnivores feed on herbivores, and herbivores feed on plants. I believe many of my friends know that most herbivores, whether they are small or large, are relatively docile, and will not fight when they encounter natural enemies, but turn around and run away.
If it is a rabbit and other small animals, it is normal for a tall and mighty natural enemy to choose to escape. But we will find that these tall, mighty-looking herbivores, such as bison and wild horses, will not actively choose to fight when they encounter carnivores like wolves, but also turn around and run.
We can imagine how ridiculous it is that a herd of bison and wild sheep are chased by some wolves smaller than them. Although it seems ridiculous to us, nature is so magical, and the instincts in the biological chain are too powerful. Even if the terrestrial overlord elephant encounters lions and tigers smaller than it, they dare not actively fight, but passively defend. Even so, there will be lone elephants eaten.
So a friend had this question: Why are herbivores generally not aggressive? Why didn’t nature choose to let them evolve? In our opinion, the main reason why herbivores choose to escape when they see carnivores is that these herbivores have not evolved powerful aggressive equipment.
Carnivores generally have powerful offensive “equipment”, such as very sharp teeth, strong bite force, sharp claws, etc. But why is such a powerful offensive equipment not common among herbivores? Nature is too partial, right?
In fact, nature is very fair in choosing the path of biological evolution, and every choice of biological evolution path is very fair, and there is no favoritism. The reason why carnivores have not evolved aggressive equipment is mainly related to their living environment and living habits.
We all know that herbivores feed on vegetation. In order to adapt to the feeding of plants, nature allows them to evolve a set of body structures that match them. Plants are completely different from meat. Vegetation is rich in cellulose, which is a very indigestible substance. Many carnivores cannot digest it, and can only excrete it after eating it. For example, we humans cannot digest this cellulose.
Herbivores can digest this cellulose. There are two main reasons for this. One is that their stomachs are very powerful, and they have multiple stomachs. In addition, the intestines of herbivores are also very long, much longer than those of carnivores.
A long intestine can keep food for a long time, which is conducive to the digestion of cellulose. Another reason is that the gastric acid concentration of herbivores is not high. We all know that the gastric acid concentration in carnivores is very high. This has the advantage that it can effectively kill microorganisms and prevent various diseases. In herbivores, the gastric acid concentration is relatively low, and microorganisms can survive in the body.
Microorganisms have a very powerful decomposition ability. They can help herbivores to decompose cellulose in plants and convert cellulose into various lipid molecules for herbivores to absorb. This is a mutually beneficial parasitic relationship. Some friends may have said that since the low gastric acid concentration helps to break down cellulose, wouldn’t it be better to reduce the gastric acid concentration of carnivores?
In fact, it is not good at all. Carnivores feed on herbivores, and herbivores have a large number of microorganisms in their bodies, and these microorganisms also enter the bodies of carnivores. In the body of herbivores, microorganisms have reached a parasitic relationship during the evolutionary process, forming a mutually beneficial relationship, so they will not cause harm to herbivores.
However, they are not friendly to carnivores. Once they enter the body of carnivores, these microorganisms will not only help decompose cellulose, but also decompose other healthy cell tissues, thus posing a threat to the health of carnivores. However, stomach acid can effectively kill these microorganisms, as long as the concentration is high, they can be eliminated, which can ensure the health of the meat eaten.
In this respect, human ancestors were very smart, learned how to drill wood to make fires, and learned that cooked food is healthier. After the food is cooked, the microorganisms in it can be eliminated in large quantities, so that after humans eat it, they will not be threatened by microorganisms. Nowadays, some people are constantly trying to eat raw meat, even if they eat meat, they only eat meat that is less than half-cooked.
This habit of eating meat is actually very bad. If the meat is not cooked well, the microorganisms in it are difficult to kill in large quantities. Once we eat it, it is easy to get sick. So here I would like to advise the majority of friends who like to eat meat to fully cook and roast meat at all times, not to eat half-cooked meat, let alone eat raw meat.
In order for herbivores to digest cellulose effectively, nature has allowed them to evolve a strong stomach, a longer intestine, and a lower concentration of gastric acid. Whether it is a more powerful stomach or a longer intestine, it consumes a lot of energy. The aggressive equipment of carnivores also consumes a lot of energy.
The total energy of living beings is limited, and only one can be selected in terms of powerful digestive equipment and offensive equipment. If the two choose at the same time, the energy will not be supplied, which is very detrimental to the evolutionary health of organisms. This is the choice made by nature for the better survival of organisms.
Moreover, the teeth of herbivores are generally large and flat rather than small and sharp like carnivores. The reason is that herbivores need to grind vegetation into small pieces with their teeth to facilitate digestion in the stomach and decomposition of microorganisms. At the same time, the eyes of herbivores are also very different from those of carnivores.
The eyes of herbivores are on both sides of the head, which has the advantage of expanding the field of vision, and can detect the dangers around them in time when eating grass. Once a natural enemy approaches, it can be spotted and jumped in time. It is important to know that herbivores have to escape frequently, their feet have evolved hooves, and their running ability is also very strong. As long as natural enemies can be spotted in time, they can escape most of the time.
Although in our opinion, herbivores live very pitifully, they do not have powerful and aggressive equipment when facing natural enemies, and can only choose to escape, but in fact, herbivores live very comfortably. They rarely worry about food. In nature, vegetation is the most abundant. You must know that in the life of nearly 500 million years, there have been five major biological extinctions on the earth, and countless biological extinctions have disappeared.
But after the mass extinction, the vegetation is the first to recover, then the herbivores, and then the carnivores. In the animal kingdom, herbivores have the strongest continuity. Therefore, in the animal kingdom today, many of the older species are basically herbivores.