Scientists found the female orgasm is an evolutionary relic – BBC

Comparison of hormone activity in a variety of placental mammals for the first time possible to understand how and why there was a female orgasm. The work, published today in the Journal of Experimental Zoology , shows that the female orgasm – an evolutionary relic of the days when he helped stimulate ovulation

inexplicable. the meaning of the female orgasm, do not play an obvious role in reproductive success, intriguing scientists since Aristotle

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in fact, if the male orgasm is closely related to ejaculation (and no fertilization will not occur without the sperm), the direct link between women orgasm, breeding success and the number of offspring from Homo sapiens is not. And if the sign is indifferent to the appearance of offspring, what it can be beneficial in evolution? To explain this paradox tried using multiple hypotheses.

two most commonly claimed that women’s orgasm or evolved hand in hand with a male as its “by-product”, or still plays a role in reproduction.

Most of the studies focused on people and other members of the primate. Researchers from Yale University and the Centre for the prevention of preterm birth Children’s Hospital in Cincinnati, disagree with anthropocentrism, presented their views on this vital topic, tracing the evolution of this trait in many different placental mammals.

Expectation vs Reality

Although mammals that live in almost all parts of our planet, is strikingly diverse, some of their features literally “run like a red thread” through their evolutionary development. For example, the ovulation cycles – maturation and release of the ovarian follicle ready to fertilize the egg. At the time of release of the egg body is ready for fertilization: the uterus is covered inside a special “lining” (endometrium) with a lot of blood vessels, where the zygote (fertilized egg) could easily be attached. When this happens, the embryo begins to develop, and the delivery of oxygen and nutrients to it through the placenta – “sostykovochny unit” that links the blood system of a woman and child, which consists of overgrown blood vessels of the endometrium.

But the rare egg drops a chance to be fertilized, and the body, freshly prepared to meet the long-awaited zygote “with a red carpet, flags and fanfare”, now contemptuously rejects the functional part of the endometrium and gets rid of it, with the result that there is menstruation.

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It is true that most of the mammalian female menstrual cycle is absent, while the endometrium is also periodically thickens. Instead, they observed estrus, or heat, when they are ready to mate, and the rest of the females of mammals are not interested in reproductive issues.

Heritage lonely ancestors

There are several ‘switch “able to transfer a female mammal in mode” active search “. In some animals ready for breeding largely depends on the season and comes at a certain temperature and the length of daylight hours, when the conditions are favorable for bearing and rearing. Such species include horses, bats, hedgehogs, the females of which ovulation occurs at certain times of the year.

But if the mammal lives alone and rarely meets representatives of their own species (camels, wolves, many cat, rabbit), spend the egg hurl female unprofitable,

so that “switch “may be the presence of a male or even the sexual act itself, and here most clearly visible part of the female orgasm.

in females of primates (including from Homo sapiens women) ovulation occurs at a time defined their internal schedule, and external factors affect it much less

Controls the mammalian ovulation the corpus luteum -. a temporary iron, formed from ovarian granulosa cells and secrete hormones (progesterone, follicle stimulating hormone, and others.). This activity of the corpus luteum hormones and became the basis for the comparison of females with all types of

«switches». It has been shown that in animals with a “switch” the second type of sexual intercourse causes neuroendocrine response, increasing prolactin, luteinizing hormone and follicle-stimulating hormones. These hormones stimulate ovulation in primates and stand on their own. Scientists believe that in females with ovulation induced by mating the main stimulus becomes a physical effect (although camels described the role of specific chemicals in the process of sperm).

So, many rodents (hamsters, rats, mice) for the delivery of artificial sperm and without physical stimulation zygote can not be attached to the walls of the uterus and grow.

also in the female placental mammals were taken into account differences in the location of the clitoris stimulation which causes a clitoral orgasm. It was found that the mammalian ovulation, depending on the males, the body is stimulated directly in the process of mating.

Analysis of ovulation types of representatives of different groups of mammals showed that our ancestors likely had ovulated with ” switch “of the second type. Therefore, the existence of the female orgasm, we should be grateful to the ancient mammals,

living alone and produce eggs in response to stimulation by the male.

Such properties of the organism, changing in the course of evolution, often acquire new functions, like feathers, hair, and other swim bladder, which originally served other purposes.