In the forests, people can easily find deer and deer skeletons in the middle of trees. The huge antlers of the males make it impossible for them to escape after being trapped and from there they cannot eat or escape from predators. They will be stuck between the branches until it is just a skeleton.
As early as 200 years ago, Darwin had the same questions, many animals seemed to preserve beauty and gradually fell to the dead end of evolution, but his object was the species at that time. peacock.
The saying “fighting for survival is the driving force of the natural selection process” seems to be a brief summary of evolution, animals will always evolve in the direction that they can continue to survive. good in nature. But right from the start of evolution theory, Darwin was skeptical of this saying. Because he really could not understand what the peacock’s tail feathers did in the process of helping them survive, and this was similar to the huge pairs of male antlers.
Regardless from the point of view, the fact that the peacock’s tail feathers are always a “heavy burden” combined with “waste, clumsiness and recklessness”. It not only consumes energy but also greatly affects the movement and operation of the male peacocks. The eye-catching color of the tail feathers attracts predators and can easily lead to their deaths.
From an evolutionary point of view, the 2-meter-long tail hair will surely be mercilessly removed by natural selection. But in reality, the male peacocks still have a long tail and flashy colors, which seems to be countering Darwin’s theory of evolution. In 1860, Darwin even admitted: “As soon as I saw the tail feathers of a male peacock, I didn’t know what to say.”
Shortly thereafter, Darwin faced similar difficulties and had to give corresponding answers. In addition to the evolution that happens as a result of adapting to the environment, there must be a certain “mysterious force” that dominates us. And in “The Origin of Mankind and Sexual Selection” published in 1871, he revealed another evolutionary trend – sexual selection.
If you want to pass on your own genes to future generations, you need more than just preserving your small existence. In addition to survival, animals have to evolve to serve another important purpose, which is to have the opportunity to mate and reproduce, and this also explains why the male peacocks still exist. At the eye-catching long tails and deer there are huge pairs of antlers.
With heterosexual animals, most males will look different and to be able to win the favor of females, they force themselves to evolve in contrast to the survival evolution to have Can own eye-catching appearance.
In theory, male peacocks losing tail feathers would be more suitable for the meaning of survival, but from the time of evolution, if they could not find an alternative method of stretching the tail, they still had could exist, but the gene transfer chain will be broken at that moment. In general they have to trade, to be able to maintain the same say to the next generation, they will have to use their lives to trade.
The evolution of the male-like eye-like appearance exists a lot in the animal kingdom, and especially for birds, such as the long-tailed ribbon-tailed bird (Astrapia mayeri) with long tail feathers. many times the length of the body.
Another example is the crown of the rooster, in addition to beauty, it is also a dangerous weakness of them. When they were pecked at by an opponent, they would easily lose a lot of blood and die. That’s why we see chicken breeders always cutting their crests right from the start.
In nature, “polygamy” species will have greater competition, the difference between the sexes will be greater. A strong male can dominate many females, so they can leave more females and spread their genes more widely. And those weak males may not have a chance to mate, and they will eventually die.
And for animals that tend to be “monogamous” we won’t find much difference between the sexes except size, because males don’t need as many females through competition from looks. out.
For example, the primates we are most familiar with for example, gorillas living near the equator on the African continent, they adopted polygamy and lived in groups, each group led by an adult male named is the “silver back” (black fur color of males over 13 years old will gradually become silvery white).
Apart from the silver backs, the other males in the pack will not have the right to mate with the female gorillas. Of course, only males with large stature and strong enough to be able to defeat the leader, it will become the new “silver back” of the herd. And in this selection process, male gorillas also evolved to become the largest primates. In contrast, in the case of a monogamous human being, the difference in size as well as body shape of the sexes is not much different.
However, in the history of the Earth, we have witnessed the extinction of many species because they evolved to preserve the beauty of an excessive scale and then suffered the end of destruction when the natural environment changed.
Sex selection is related to the general breeding plan of the entire population, but when an animal invests too much energy or over-inhibits its ability to survive, it will also cause catastrophe. Especially when the environment changes. Theoretically, species with greater gender differences will be at higher risk of extinction. Therefore, during the evolution of the species, natural selection and sex selection should examine and balance each other.