conversationJune 23, 2021 11:47:52 AM IS
Charles Darwin was a diligent scientist. In the mid-19th century, he was gathering evidence to support his theory that species evolved Natural selection, He noted that it didn’t explain why a male peacock’s showy tail, the antlers carried by a male deer, or some of the males of some species were much larger than their female counterparts. It was.
For this habit, Darwin proposed a quadratic theory: Sexual selection With a trait that increases the likelihood of animals securing their spouse and brood, he will attract the opposite sex with weapons such as horns, spurs, fangs, and large weapons that are used to control competing rivals. Carefully distinguished the ornaments for.
The scientist Charles Darwin proposed a secondary theory. It is a sexual selection of traits that increases the likelihood that an animal will secure a spouse and brood. Image source: Wikipedia
Darwin believed that sexually selected traits could be explained by heterogeneous gender relationships – if the population had more men than women, or vice versa. He thought Men with a small number of women available will have to work harder to win one of them as a spouse, and this competition will encourage sexual selection.
so New research, My colleague and I confirmed the link between sexual selection and gender relations, as Darwin suggested. But surprisingly, our results suggest that Darwin went the wrong way. It was found that sexual selection was most pronounced when the prospective spouse was abundant, not when it was low. This means rethinking the selection pressure in animal populations that are characterized by heterogeneous gender relationships.
Since the days of Darwin, we have learned a great deal about the heterogeneous gender relationships that are common in wildlife populations. For example in many cases butterfly And Mammal-The number of adult women, including humans, exceeds the number of adult men.
This crookedness is the most extreme Between marsupials .. For example, in Antekinus, Australia, all are men Suddenly die After the mating season, adult males may no longer be alive and the entire adult may be made up of pregnant females.
In contrast, many birds have more males than females in their populations. Some plovers, e.g. Outperforms women 6 to 1.
Why do mammals have more females while many species of birds have more males? Simply put, we don’t know. But there are smoking guns.
Description of the inconsistent gender ratio
Some inconsistent gender ratios can be partially explained Difference in life .. female mammal, They usually live significantly longer than their male counterparts, including humans. In humans, women live on average about 5 percent longer As men African lion And Orca, The lifespan of women is up to 50 percent longer.
Predator preferences can also play a role. African lions almost kill 7 times or more Male buffalo tend to roam alone, while females are more male buffalo than female buffalo because they are protected in the herd. In contrast, the cheetah kills More women The Thomson gazelle is likely to be easier to overtake than a male gazelle, especially a pregnant gazelle.
After all, men and women often Another ailment Of parasites and diseases. The COVID-19 pandemic is a prominent example of this. The number of men and women infected is the same in most countries, but male patients High probability of death Compared to women.
Gender balance and sexual selection
Despite increasing knowledge of heterogeneous gender relationships, Darwin’s findings that link gender relationships with sexual selection have received little attention from scholars. Our study attempted to address this by bringing these two evolutionary strands together to rethink Darwin’s argument.
I paid special attention to evolution Big man In different species, it is often many times larger than its female counterpart Male baboon, elephant seal And Migratory bird, For example.
Sometimes women are taller than men – as is the case with some bird species, African jacana, etc. The scientific terms for when one sex of one species is greater than the other is: “” Sexual Dimorphism “.
The method is clear Sexual selection Can produce dimorphism in size. Killing enemies takes strength, but combat stamina takes stamina. Growing up therefore often means dominating rivals and thereby winning the evolutionary lottery of reproduction.
In analyzing 462 reptiles, mammals, and birds, our study found a close relationship between gender dimorphism and gender ratio, which supports Darwin’s speculations.
But this trend was the opposite of what Darwin had predicted with limited evidence. It found that the strongest sexual selection occurred in species with a large number of females to choose from, rather than a lack of females as Darwin suggested.
Influence on sexual selection
This does not invalidate Darwin’s theory of natural selection and sexual selection. Our results merely indicate that a mechanism other than that proposed by Darwin promotes mating competition for animals living in sexually distorted populations.
Darwin’s assumption was based on the idea that the toughest competition for mating partners should take place when there is a lack of mating partners Newer theory This logic may not be correct and suggests that sexual selection is indeed a system where the winner takes everything.
That is, if the population has many potential partners, the top males (the largest and heaviest in our study) will receive disproportionately high payments and will fertilize large numbers of females at the expense of the small males. .. all.
Further research to help men and women find new partners in a group of male and female skewers, and in what situations ornaments, weapons, and size sizes are particularly useful. Required. Such studies can give us unprecedented new insights into how nature works, based on Darwin’s original theory of sexual selection.
Tamas Zeckery, Professor of Biodiversity, Milner Evolution Center, University of Bath
This article is republished from the conversation under a Creative Commons license. Read the original work ..
Charles Darwin may have reversed sexual selection, new research suggests-Technology News, Firstpost
Source Link Charles Darwin May Have Reversed Sexual Selection, New Research Suggests-Technology News, Firstpost
