Scientists have proved once again that sex is good for health. The researchers note that favorable results will be especially noticeable if you make love at least once a week. Scientists have discovered a surprising number of therapeutic properties of sex, from prolonging life and ending with an analgesic effect.
Studies do not indicate whether the improving effect of sex consequence of the sexual act, or the emotions experienced by people during intimacy. However, sex has a very beneficial impact on the physical condition of man. This is especially true of women. Scientists are six ways to impact of sex on human health:
1. Sex can cure colds and flu. According to the research of scientists from Uilkskogo University in Pennsylvania, sex 1-2 times a week is capable of three-fold increases of immunostimulatory antibodies - immunoglobulin A, which protect the organism from respiratory viruses.
2. Sex - better cabinet cosmetologist. In the course of study at the Royal Edinburgh Hospital Group of Experts considered the people of different ages through one-way mirror and the making of assumptions about their age. Participants of the study that looked, according to experts, under the age of 7-12 years, on average, had sex 4 times a week. Scientists believe that regular sex is to help them look younger. One of the reasons - sex increases the level of estrogen in the blood of women, which makes their hair shiny and skin - elastic.
3. Sex burns calories. During sex burns more than 4 calories per minute. For half an hour of love you could spend the calories obtained by eating four chocolate candies. So consider sex as a way of daily sport.
4. Sex cures migraines. Women headache is the main reason to make love, not abandon it. The hanging of the level of endorphins and corticosteroids in the blood during arousal and orgasm is an excellent analgesic.
5. Sex stabilizes the menstrual cycle. A number of studies conducted by endocrinologists at Columbia and Stanford universities found that women who have sex weekly, cycle more regular than abstaining or resorting to congress from time to time. (A similar study showed that even the lesbian caresses a beneficial effect on menstrual cycle). The researchers argue that the very intimacy is important, but not orgasm.
6. Sex may be free from troubles. Women use the muscles of the pelvic floor to contain the urine. With age, they wear out, so we have to make greater efforts to avoid accidental urination. Those muscles can be trained during sex - with a better way simply does not exist.
Sunday, November 22, 2009
Sex for the first time
The first sexual experience is firmly imprinted in the minds of all persons, regardless of his wishes. Especially important is it for women as being more receptive and emotional. Unsuccessful first experience very often becomes the cause of female frigidity, its indifference to sex, inability to experience orgasm, sexual disharmony and its negative attitude towards men in general.
And she will be lucky if its first partner will be a man knowledgeable, experienced, discreet and cautious. Loving, of course. Because all its subsequent connection, it will not help to pass through the impression and feeling its very first night. What are they? Pleasant, not at all or terrible? In large measure this depends on her ...
The first time, usually painful and frightening, and unpleasant. And, if the partner is rude and inconsiderate, and even bitter. And do not believe their "experienced" minor girlfriend, who first ascended to heaven and experienced heavenly delight. This is a lie! It is even physiologically impossible, because the traumatic (even if the hymen is elastic, not break, and stretchy natural barrier). Even if the first man experienced, and attentive, and loving, it is unlikely she will be able to experience orgasm. It is rather an exceptional case than the rule.
And if proximity is of the same age, the same young and inexperienced, as it is, some not too pleasant, and even curious moments, alas, can not be avoided. But everything is reparable, if young people go to it for love, emotional attachment, knowingly and voluntarily. And most importantly balanced. And if it happens otherwise? Incidentally, out of stupidity, because of fear ...
From this absurd and painful experience she often makes the impression of experiencing frustration and aversion to sex sometimes for many years. Again, many women's sex problems are connected with the first failed sexual experience.
Why are girls still go to it
1. Due to differences in motivations and levels of sexual development guys and girls in their teens and early adolescence. It relates to how they look at the issues of love and friendship. The girl aged 14 - 18 years interested in the question of romantic love, platonic love relationships, gentle friendship. They love to read romance novels and watch melodramas and imagined relations between men and women in beautiful and romantic spirit of mutual sympathy, benevolence, respect and tenderness. They are in our dreams are very far from the animal instincts and impulses of the flesh, which is still dormant in them. Manifestation of activity on the part of young men frightens them, repels, confusing and even frustrating. Sexuality wake them much later. Boys also about 17 - 24 years, first unconsciously, and then all definitely have quite specific personal desire for closeness with the girl. They want sex. And not matured yet to the high spiritual relationship with the woman. She will have them later in adulthood. And while their lead with a tremendous shock to the body. The girls, not realizing this, gives his desires, taking them for their love of high spiritual order. Very often invented relationship deducted from romance novels and podsmotreny in the movies seem to be love, and she decided at the first attempt. Some girls do not realize that they are playing with fire, revealing the seductive part of its shape, legs, chest. They provoke the boys their clothes, behavior, like allowing them a wish. Most guys are very hard to resist this. So there are random and early communication, due to a desire to unbearable intimacy. Unfortunately, they are far from true love and intimacy, but inexperienced young people are perceived this way.
2. The girl behind the requests, desires and threats because of the fear of rejection, ridicule be worse than the other, differ from the collectively formed the image of "his girls", who dominates her social peers. That is going to take this step out of fear. But not for love. Sometimes it happens by accident in a state of uncontrolled and unconscious drive under the influence of alcohol. In such cases, the girl is not immune from anything. Especially if it is not too picky acquaintances, and among her entourage have guys with questionable reputations. To anything good this experience does not lead, as a rule. And great love, and especially marriage, what each secret dreams, here and does not smell.
3. Some modern girls have a sexual relationship as outrageous, in retaliation, in order to annoy their parents, in order to pass for peer advanced, for the sake of interest, to look older, more attractive in the eyes of the opposite sex. Most of these eksperimentatorsh grow cynical and indifferent to the normal human women. They reduce any gender relations to the bed, they thrive in the art of bodily pleasures. But few of them able to really relax during sex. Because promiscuous and experiments, alas, does not enhance their femininity, and destroy him, emptying their souls, which loses the ability to complicity, empathy, and a thin inner feelings of another person. I do not believe that the best wife went to prostitutes. For the simple reason that the best wife - is, above all, a person close. Spiritually close. You can learn relaxation techniques with thousands of bed, learn to play thousands of sexual games, but never learn to be a woman, soft, kind and tolerant to one single person who becomes your husband.
When a woman sells her body for many, whether for the sake of experiment and my own pleasure or for money, she unlearns feel selfless love. She loses herself as a woman, with each new partner without acquiring and losing part of his soul. Because that was the way her body, it can not exist apart from the mind and heart. Because sexual activity is included her entire body. When it comes to sex, she gets a man's strength and energy of the solid plan, but gave part of his inner being.
When this happens, and happens naked sex, women in this "woman" are no longer or not yet.
I admit that this is merely a subjective opinion of the author, and that modern life is more loyal to the issues of sex. But no one can convince me that by engaging in a sexual relationship with a man, woman never thinks about love, even for a moment, though out of the corner of his consciousness, and concerned only with the obvious question sexual release, or opportunity to practice in bed. Show me the woman I want to look into her eyes!
I think for every girl's question, the first night - one of the most important questions of life. In spite of everything. Because it creates all of her future life with men, and is directly related to her happiness. Therefore, it should treat it as possible carefully and responsibly.
I think in any case, it should not:
• Hurry up.
• Striving to be like everyone else. Adjusting to the standards and requirements of fashion (which may be a fashion, if we are talking about your own life, which is given to you only once, and to correct, amend and alter anything in it already will never have!).
• AFRAID be rejected (love, real love, if it has a place to be, do not check such dubious means).
• attending this irresponsible, careless, thoughtless, without considering possible consequences.
• DO IT FOR EXPERIMENTS WITH dubious character. And if you dare to know everything in this life, choose a partner without aggravating circumstances.
• do so on the Staircase in the basement, through the gateway, etc. There is a risk that you will not like this is extremely, and turn away from it all.
• GO FOR IT, IF YOU ARE NOT SURE, that you love this man. Try to find out whether you love or "just because" some other way. You'll see, soon it will become clear to you and without sex.
• Binds man So, if you want a man, not a male. There is a risk that, to satisfy his desire, he just throws you. Man, that a woman need only this tie is impossible, because sooner or later, on his way to meet other, more attractive female, and draw it into the new network.
• use sex as a provocation and blackmail. Unless you do not Mata Hari, it is unlikely to make you happy. And for what it was all over, remember ...
I think that the feeling of happiness for women as for men, not due to sexual release, but with the concepts of higher and subtle plan. Spiritual closeness, love, respect, human warmth. And, of course, harmonious, deep and comprehensive physical contact, which can not happen in a hurry, in the hallway, as horrible and with just anyone ... So why are you your first most important experience of life rush and lets things slide? To the rest of his life he stood over you like Damocles' sword of your women unhappy? You do not want to! So do not rush to become a woman, the more so with a sense and knowledge of their femininity is related only formally ...
And she will be lucky if its first partner will be a man knowledgeable, experienced, discreet and cautious. Loving, of course. Because all its subsequent connection, it will not help to pass through the impression and feeling its very first night. What are they? Pleasant, not at all or terrible? In large measure this depends on her ...
The first time, usually painful and frightening, and unpleasant. And, if the partner is rude and inconsiderate, and even bitter. And do not believe their "experienced" minor girlfriend, who first ascended to heaven and experienced heavenly delight. This is a lie! It is even physiologically impossible, because the traumatic (even if the hymen is elastic, not break, and stretchy natural barrier). Even if the first man experienced, and attentive, and loving, it is unlikely she will be able to experience orgasm. It is rather an exceptional case than the rule.
And if proximity is of the same age, the same young and inexperienced, as it is, some not too pleasant, and even curious moments, alas, can not be avoided. But everything is reparable, if young people go to it for love, emotional attachment, knowingly and voluntarily. And most importantly balanced. And if it happens otherwise? Incidentally, out of stupidity, because of fear ...
From this absurd and painful experience she often makes the impression of experiencing frustration and aversion to sex sometimes for many years. Again, many women's sex problems are connected with the first failed sexual experience.
Why are girls still go to it
1. Due to differences in motivations and levels of sexual development guys and girls in their teens and early adolescence. It relates to how they look at the issues of love and friendship. The girl aged 14 - 18 years interested in the question of romantic love, platonic love relationships, gentle friendship. They love to read romance novels and watch melodramas and imagined relations between men and women in beautiful and romantic spirit of mutual sympathy, benevolence, respect and tenderness. They are in our dreams are very far from the animal instincts and impulses of the flesh, which is still dormant in them. Manifestation of activity on the part of young men frightens them, repels, confusing and even frustrating. Sexuality wake them much later. Boys also about 17 - 24 years, first unconsciously, and then all definitely have quite specific personal desire for closeness with the girl. They want sex. And not matured yet to the high spiritual relationship with the woman. She will have them later in adulthood. And while their lead with a tremendous shock to the body. The girls, not realizing this, gives his desires, taking them for their love of high spiritual order. Very often invented relationship deducted from romance novels and podsmotreny in the movies seem to be love, and she decided at the first attempt. Some girls do not realize that they are playing with fire, revealing the seductive part of its shape, legs, chest. They provoke the boys their clothes, behavior, like allowing them a wish. Most guys are very hard to resist this. So there are random and early communication, due to a desire to unbearable intimacy. Unfortunately, they are far from true love and intimacy, but inexperienced young people are perceived this way.
2. The girl behind the requests, desires and threats because of the fear of rejection, ridicule be worse than the other, differ from the collectively formed the image of "his girls", who dominates her social peers. That is going to take this step out of fear. But not for love. Sometimes it happens by accident in a state of uncontrolled and unconscious drive under the influence of alcohol. In such cases, the girl is not immune from anything. Especially if it is not too picky acquaintances, and among her entourage have guys with questionable reputations. To anything good this experience does not lead, as a rule. And great love, and especially marriage, what each secret dreams, here and does not smell.
3. Some modern girls have a sexual relationship as outrageous, in retaliation, in order to annoy their parents, in order to pass for peer advanced, for the sake of interest, to look older, more attractive in the eyes of the opposite sex. Most of these eksperimentatorsh grow cynical and indifferent to the normal human women. They reduce any gender relations to the bed, they thrive in the art of bodily pleasures. But few of them able to really relax during sex. Because promiscuous and experiments, alas, does not enhance their femininity, and destroy him, emptying their souls, which loses the ability to complicity, empathy, and a thin inner feelings of another person. I do not believe that the best wife went to prostitutes. For the simple reason that the best wife - is, above all, a person close. Spiritually close. You can learn relaxation techniques with thousands of bed, learn to play thousands of sexual games, but never learn to be a woman, soft, kind and tolerant to one single person who becomes your husband.
When a woman sells her body for many, whether for the sake of experiment and my own pleasure or for money, she unlearns feel selfless love. She loses herself as a woman, with each new partner without acquiring and losing part of his soul. Because that was the way her body, it can not exist apart from the mind and heart. Because sexual activity is included her entire body. When it comes to sex, she gets a man's strength and energy of the solid plan, but gave part of his inner being.
When this happens, and happens naked sex, women in this "woman" are no longer or not yet.
I admit that this is merely a subjective opinion of the author, and that modern life is more loyal to the issues of sex. But no one can convince me that by engaging in a sexual relationship with a man, woman never thinks about love, even for a moment, though out of the corner of his consciousness, and concerned only with the obvious question sexual release, or opportunity to practice in bed. Show me the woman I want to look into her eyes!
I think for every girl's question, the first night - one of the most important questions of life. In spite of everything. Because it creates all of her future life with men, and is directly related to her happiness. Therefore, it should treat it as possible carefully and responsibly.
I think in any case, it should not:
• Hurry up.
• Striving to be like everyone else. Adjusting to the standards and requirements of fashion (which may be a fashion, if we are talking about your own life, which is given to you only once, and to correct, amend and alter anything in it already will never have!).
• AFRAID be rejected (love, real love, if it has a place to be, do not check such dubious means).
• attending this irresponsible, careless, thoughtless, without considering possible consequences.
• DO IT FOR EXPERIMENTS WITH dubious character. And if you dare to know everything in this life, choose a partner without aggravating circumstances.
• do so on the Staircase in the basement, through the gateway, etc. There is a risk that you will not like this is extremely, and turn away from it all.
• GO FOR IT, IF YOU ARE NOT SURE, that you love this man. Try to find out whether you love or "just because" some other way. You'll see, soon it will become clear to you and without sex.
• Binds man So, if you want a man, not a male. There is a risk that, to satisfy his desire, he just throws you. Man, that a woman need only this tie is impossible, because sooner or later, on his way to meet other, more attractive female, and draw it into the new network.
• use sex as a provocation and blackmail. Unless you do not Mata Hari, it is unlikely to make you happy. And for what it was all over, remember ...
I think that the feeling of happiness for women as for men, not due to sexual release, but with the concepts of higher and subtle plan. Spiritual closeness, love, respect, human warmth. And, of course, harmonious, deep and comprehensive physical contact, which can not happen in a hurry, in the hallway, as horrible and with just anyone ... So why are you your first most important experience of life rush and lets things slide? To the rest of his life he stood over you like Damocles' sword of your women unhappy? You do not want to! So do not rush to become a woman, the more so with a sense and knowledge of their femininity is related only formally ...
On the nature of sex
How did sex? No answer - puzzle to be solved Science XXI century. But there is a hypothesis: according to one of them, this is a side effect of the biochemical mechanism of repair of damaged genes, which arose more than a billion years ago. Evolution proved - sex useful. Actually, we have this and so have guessed. Science has given to rational arguments
Sex appeared already in the far-celled human ancestors more than a billion years ago. Virtually all animals (with very rare exceptions) can reproduce sexually. Even at jellyfish there are male and female. Those animals which are deprived of this happiness (eg, some species of lizards), which undoubtedly had ancestors that reproduce sexually.
Why sex?
Sexual reproduction is so widespread in nature, that until the XIX century, people did not even ask why animals and plants reproduce by mating or otherwise a combination of germ cells. This question arose in the middle of the XIX century in connection with the proliferation of Charles Darwin's theories of evolution and natural selection. After all, according to this theory, so that sexual reproduction was maintained, it should help the survival of the species, and "profit" must be greater than the cost of sexual reproduction. Otherwise, the continuation of the species - including human - nature would have found something better.
Price sexual reproduction
Every action has its price. Reproduction with sex - is also very expensive. Flowering plants are forced to work, produce nectar to attract bees that carry pollen from flower to flower, helping plants carry out sexual reproduction. A male species Homo Sapiens, for example, are forced to buy interesting sports car to attract girls, girls - well, we know that "The Devil Wears Prada" ...
In addition, only half of sexually reproducing species - a female - to bear children. If the population of creatures that reproduce sexually, there was a mutant, gemmate, then ceteris paribus (eg birth, on average 2 -3 children), the descendants of this mutant can easily be replaced descendants couples sexual beings - only after 11 generations the difference in the number of offspring would be more than 1000 times (211 / 2 = 1024). Why do we still reproduces sexually? The answer to this question became clear only after the development of genetics.
From the standpoint of genetics
Charles Darwin believed that the existence of sex for the benefit of heterosis - the effect of increased survival of hybrids of different breeds of animals are often observed in animal husbandry: it is known that, say, mestizos of different breeds of horses are running faster than their "clean" relatives. But the nature, of course, the races do not care - she wondered survival of species. At the same time Charles Darwin could not explain the nature of this effect, because it was assumed that the heredity of two parents is mixed, like the blue and red paint, which results in a cross - purple paint.
Following the work of Gregor Mendel, August Weismann and other pioneers of genetics XIX century explanation of the usefulness of sex was found. According to genetics, each person carries two sets of genes: one obtained from the mother, the other - from the father. Moreover, because of the shuffling of genes in a process called crossing-over, the person receives a rather complex collection of genes from all of their grandparents. But genes sometimes accrue broken - defective. So, genetics has shown that the healthy gene, derived from the father, can cover the negative effect of the defective gene, derived from the mother, and - contrary. It became clear observation of Charles Darwin on the high survivability hybrids of different breeds of animals.
However, the persistence of mixed parentage is not the main advantage of sexual reproduction. Much more important is the possibility of a combination of several positive mutations. This phenomenon is most evident in bacteria. While the bacteria multiply by simple division, in some species, there is sex in the form of exchange of genetic material through a special hose (pilus), which the bacteria are connected with each other, as aircraft during refueling in the air. That way bacteria communicate with each other resistance genes to each newly-opened medical antibiotic. Without sex bacteria would require Millennium to consistently acquire all mutations that protect them from several antibiotics. Because of the sex they can acquire these mutations independently and then share their accomplishments.
Evolution puts on selfish
Explanations of the usefulness of sex for survival of the species considered to be sufficient until 1962, when the British zoologist VaynEdvards began to dispute about the essence of Darwinism in American biologist George Williams. Edwards thought that evolution selects species, and Williams was convinced (and failed to substantiate), that evolution selects individuals, selfish. According to Williams, a hare in the woods does not compete with the wolf, but with another hare. If one rabbit will run slightly faster than the other rabbit, it is another hare will be eaten by wolves, thus providing an evolutionary victory of the first hare.
In other words, any trait of an organism (including sex) will be assigned an evolution only if this feature is now helping a specific individual, rather than the whole of his mind in the abstract future. A large number of observations and mathematical models have confirmed the correctness of "individualist" Williams. Still further, this theory was developed by Richard Dawkins, who generally said that the true evolution of the players are not the kinds and even individuals, and genes. Body - this is only way to ensure a future for the gene.
Politically incorrect sex After the book Dawkins' "Selfish Gene" many researchers have made attempts to explain human sexual behavior as imposed on its genes optimal strategy transfer these genes into the future.
Matt Ridley, for example, showed how people evolved in small groups, living in the African savanna. In this environment, genes men prompted him to have one wife and the maximum number of mistresses. My wife - for the birth of children, which he handed over his status in the group, and a mistress - for the widest possible dissemination of their genetic material. A genetically-based strategies of women, according to Ridley, there was another - to become his wife "a reliable breadwinner" for the sustenance of children, but at the time of ovulation to try to get genes from accidentally running through a number of "pirate" with a "high quality" genes than her husband.
When people began to build cities and big states, this genetically based strategies led to the formation of societies where the majority of women have been usurped by the big bosses (kings) and specialized Don Juan. The rulers of China, the Inca Empire, Babylon had thousands of concubines - and the "beloved wife" for the transfer status. In ancient Rome, the slave-owners did not hesitate used for sexual purposes of his slaves, leaving most of the men-slaves without women.
By Ridley, these trends have led to a lot of violence and low level of cooperation among men in the ancient world. In his book, Ridley suggested that the fall of the Roman Empire in the face of Germanic barbarians were partially due precisely to the fact that the Germanic tribes existed firmly implanted monogamy, which helped the men to unite against a common enemy - in Rome.
Why is sex does not go away?
Biologist George Williams explained this way. Suppose, in a forest tree growing. It produces thousands of seeds that may fall into a variety of places - sun or shade, wet or dry. Therefore, it is important for the tree to produce various offspring - with more or less long roots, varying in height of the barrel. Descendants will compete with each other, and the most successful survive. In other words, Williams believed that sex produces a variety, in which the brothers compete with each other.
The opposite hypothesis suggested American biologist Michael Giselin. He believed that, on the contrary, Sex and the associated diversity allows the brothers to avoid competition with each other, as they begin to occupy slightly different ecological niches. For analogy, suppose that in a small village lives a family of a blacksmith. If all five children of a blacksmith inherit his craft, the four of them will die of hunger, because the country needs only one blacksmith. But if they will have different professions (weavers, carpenters), then their total income will be greater, because they will not compete for a place under the sun.
The third hypothesis suggested American biologist Leigh Van Valen. It was called "Red Queen hypothesis, named character from the works of Lewis Carroll. For the Red Queen in Carroll scamper was the only way to stay in place. According to Van Valin, sex emerged as a way of dealing with individual parasites. In the course of this struggle, there are no victories - the individual and parasites evolve at the same time, staying in one place in relation to each other because of the simultaneous "arms race".
Finally, in the last two decades, a great contribution to the clarification of the question "Why is sex" has made Russian-American biologist Alexei Kondrashov, who emigrated from Russia to the U.S. in 1991. According to the theory Kondrashov, sex in the first place need not to useful combinations of genes, and for the combination and removal of populations of harmful genes. Each of us, the representative of the species Homo Sapiens, has dozens of new mutations that were not present for our parents. Most of these mutations have no impact, some (about 1%) are harmful, a very small part is useful.
Sex, by Kondrashov, allows to collect a combination of harmful genes in a lean subgroup of individuals, then these "specially damaged" die "cleansing", as a vacuum cleaner, its population from the harmful mutations.
Getting started
Theories Williams, Giselina, Van Valin and Kondrashov explain why sex retains its usefulness, and not replaced, say, budding. Unfortunately, they do not explain how sex arose. Many hypotheses. Unknown - even more. Find the answer - the task of science of the future.
Sex appeared already in the far-celled human ancestors more than a billion years ago. Virtually all animals (with very rare exceptions) can reproduce sexually. Even at jellyfish there are male and female. Those animals which are deprived of this happiness (eg, some species of lizards), which undoubtedly had ancestors that reproduce sexually.
Why sex?
Sexual reproduction is so widespread in nature, that until the XIX century, people did not even ask why animals and plants reproduce by mating or otherwise a combination of germ cells. This question arose in the middle of the XIX century in connection with the proliferation of Charles Darwin's theories of evolution and natural selection. After all, according to this theory, so that sexual reproduction was maintained, it should help the survival of the species, and "profit" must be greater than the cost of sexual reproduction. Otherwise, the continuation of the species - including human - nature would have found something better.
Price sexual reproduction
Every action has its price. Reproduction with sex - is also very expensive. Flowering plants are forced to work, produce nectar to attract bees that carry pollen from flower to flower, helping plants carry out sexual reproduction. A male species Homo Sapiens, for example, are forced to buy interesting sports car to attract girls, girls - well, we know that "The Devil Wears Prada" ...
In addition, only half of sexually reproducing species - a female - to bear children. If the population of creatures that reproduce sexually, there was a mutant, gemmate, then ceteris paribus (eg birth, on average 2 -3 children), the descendants of this mutant can easily be replaced descendants couples sexual beings - only after 11 generations the difference in the number of offspring would be more than 1000 times (211 / 2 = 1024). Why do we still reproduces sexually? The answer to this question became clear only after the development of genetics.
From the standpoint of genetics
Charles Darwin believed that the existence of sex for the benefit of heterosis - the effect of increased survival of hybrids of different breeds of animals are often observed in animal husbandry: it is known that, say, mestizos of different breeds of horses are running faster than their "clean" relatives. But the nature, of course, the races do not care - she wondered survival of species. At the same time Charles Darwin could not explain the nature of this effect, because it was assumed that the heredity of two parents is mixed, like the blue and red paint, which results in a cross - purple paint.
Following the work of Gregor Mendel, August Weismann and other pioneers of genetics XIX century explanation of the usefulness of sex was found. According to genetics, each person carries two sets of genes: one obtained from the mother, the other - from the father. Moreover, because of the shuffling of genes in a process called crossing-over, the person receives a rather complex collection of genes from all of their grandparents. But genes sometimes accrue broken - defective. So, genetics has shown that the healthy gene, derived from the father, can cover the negative effect of the defective gene, derived from the mother, and - contrary. It became clear observation of Charles Darwin on the high survivability hybrids of different breeds of animals.
However, the persistence of mixed parentage is not the main advantage of sexual reproduction. Much more important is the possibility of a combination of several positive mutations. This phenomenon is most evident in bacteria. While the bacteria multiply by simple division, in some species, there is sex in the form of exchange of genetic material through a special hose (pilus), which the bacteria are connected with each other, as aircraft during refueling in the air. That way bacteria communicate with each other resistance genes to each newly-opened medical antibiotic. Without sex bacteria would require Millennium to consistently acquire all mutations that protect them from several antibiotics. Because of the sex they can acquire these mutations independently and then share their accomplishments.
Evolution puts on selfish
Explanations of the usefulness of sex for survival of the species considered to be sufficient until 1962, when the British zoologist VaynEdvards began to dispute about the essence of Darwinism in American biologist George Williams. Edwards thought that evolution selects species, and Williams was convinced (and failed to substantiate), that evolution selects individuals, selfish. According to Williams, a hare in the woods does not compete with the wolf, but with another hare. If one rabbit will run slightly faster than the other rabbit, it is another hare will be eaten by wolves, thus providing an evolutionary victory of the first hare.
In other words, any trait of an organism (including sex) will be assigned an evolution only if this feature is now helping a specific individual, rather than the whole of his mind in the abstract future. A large number of observations and mathematical models have confirmed the correctness of "individualist" Williams. Still further, this theory was developed by Richard Dawkins, who generally said that the true evolution of the players are not the kinds and even individuals, and genes. Body - this is only way to ensure a future for the gene.
Politically incorrect sex After the book Dawkins' "Selfish Gene" many researchers have made attempts to explain human sexual behavior as imposed on its genes optimal strategy transfer these genes into the future.
Matt Ridley, for example, showed how people evolved in small groups, living in the African savanna. In this environment, genes men prompted him to have one wife and the maximum number of mistresses. My wife - for the birth of children, which he handed over his status in the group, and a mistress - for the widest possible dissemination of their genetic material. A genetically-based strategies of women, according to Ridley, there was another - to become his wife "a reliable breadwinner" for the sustenance of children, but at the time of ovulation to try to get genes from accidentally running through a number of "pirate" with a "high quality" genes than her husband.
When people began to build cities and big states, this genetically based strategies led to the formation of societies where the majority of women have been usurped by the big bosses (kings) and specialized Don Juan. The rulers of China, the Inca Empire, Babylon had thousands of concubines - and the "beloved wife" for the transfer status. In ancient Rome, the slave-owners did not hesitate used for sexual purposes of his slaves, leaving most of the men-slaves without women.
By Ridley, these trends have led to a lot of violence and low level of cooperation among men in the ancient world. In his book, Ridley suggested that the fall of the Roman Empire in the face of Germanic barbarians were partially due precisely to the fact that the Germanic tribes existed firmly implanted monogamy, which helped the men to unite against a common enemy - in Rome.
Why is sex does not go away?
Biologist George Williams explained this way. Suppose, in a forest tree growing. It produces thousands of seeds that may fall into a variety of places - sun or shade, wet or dry. Therefore, it is important for the tree to produce various offspring - with more or less long roots, varying in height of the barrel. Descendants will compete with each other, and the most successful survive. In other words, Williams believed that sex produces a variety, in which the brothers compete with each other.
The opposite hypothesis suggested American biologist Michael Giselin. He believed that, on the contrary, Sex and the associated diversity allows the brothers to avoid competition with each other, as they begin to occupy slightly different ecological niches. For analogy, suppose that in a small village lives a family of a blacksmith. If all five children of a blacksmith inherit his craft, the four of them will die of hunger, because the country needs only one blacksmith. But if they will have different professions (weavers, carpenters), then their total income will be greater, because they will not compete for a place under the sun.
The third hypothesis suggested American biologist Leigh Van Valen. It was called "Red Queen hypothesis, named character from the works of Lewis Carroll. For the Red Queen in Carroll scamper was the only way to stay in place. According to Van Valin, sex emerged as a way of dealing with individual parasites. In the course of this struggle, there are no victories - the individual and parasites evolve at the same time, staying in one place in relation to each other because of the simultaneous "arms race".
Finally, in the last two decades, a great contribution to the clarification of the question "Why is sex" has made Russian-American biologist Alexei Kondrashov, who emigrated from Russia to the U.S. in 1991. According to the theory Kondrashov, sex in the first place need not to useful combinations of genes, and for the combination and removal of populations of harmful genes. Each of us, the representative of the species Homo Sapiens, has dozens of new mutations that were not present for our parents. Most of these mutations have no impact, some (about 1%) are harmful, a very small part is useful.
Sex, by Kondrashov, allows to collect a combination of harmful genes in a lean subgroup of individuals, then these "specially damaged" die "cleansing", as a vacuum cleaner, its population from the harmful mutations.
Getting started
Theories Williams, Giselina, Van Valin and Kondrashov explain why sex retains its usefulness, and not replaced, say, budding. Unfortunately, they do not explain how sex arose. Many hypotheses. Unknown - even more. Find the answer - the task of science of the future.
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