Biologists offer a new way of thinking about based on a reconstruction of their evolutionary heritage pleasure.
The eyes are for seeing, nose to smell. Many aspects of the human body have purposes that are obvious. However, some defy easy explanation. For biologists, few phenomena are as mysterious as the female orgasm
Although orgasm has an important role in intimate relationships of women, has been difficult to discover the evolutionary roots of experience. Combination muscle contraction, release of hormones and intense pleasure.
for decades, researchers have proposed theories, but none is widely accepted. Now, two evolutionary biologists have joined the fray, offering a new way of thinking about the female orgasm based on a reconstruction of its ancient history.
On Monday, in the Journal of Zoology experimental , the authors conclude that the response in mammals originated over 150 million years ago as a way to release eggs that are fertilized for after copulation. So far, few scientists have investigated the biology of animals with a distant relationship for clues to solve the mystery.
“Because orgasms, the reserve for humans and primates,” said Mihaela Pavlicev , an evolutionary biologist at the Faculty of medicine at the University of Cincinnati and author of the new paper. “We do not focus on other species to dig deeper and find the source,” he said.
The male orgasm has never caused great furor among evolutionary biologists. Pleasure is precisely linked with ejaculation, the most important step for transmitting the male or male genes to the next generation. That pleasure motivates men emit more sperm, which is an advantage in evolutionary terms.
For women, it is more difficult to figure out the evolutionary path. Muscle contractions that occur during orgasm are not essential for pregnant women. And while most men can experience an orgasm during sex, is less reliable for women.
In a 2010 survey, more than 35% of women said they had not had an orgasm the most recent time they had sex. Part of the reason for this is the anatomy: the clitoris is physically separated from the vagina. Either way, many scientists suspect that female orgasm serves some biological function favored by natural selection. Just need to find out what it is.
“My gut instinct tells me something that is so important in emotional terms-the intense pleasure of orgasm, obviously would have reproductive consequences,” he said David A. Puts , an evolutionary anthropologist at Pennsylvania State University.
the
skepticism
many hypotheses have been proposed. Puts and his colleagues have conducted studies to test the possibility that orgasms increase the likelihood that a woman’s eggs for attractive genetically man be fertilized.
Elisabeth A. Lloyd , a philosopher at the University of Indiana, do not believe it. She published a book in 2005 entitled “The argument of the female orgasm”, which reviewed 18 published theories about its function.
None had firm evidence in his favor, he concluded, and many were undermined by other findings about human sexuality. Years of research have only strengthened further skepticism.
Lloyd believes the best explanation is that female orgasm has not served a single evolutionary purpose. It is more than a product derived from the development of the male orgasm.
The orgasm is for women, create, which nipples are for men. However, Pavlicev and his colleague, Gunter P. Wagner Yale University, are exposing the argument that the female orgasm is a deep human evolutionary history that dates back to the earliest mammals.
started by more familiar with the sex lives of other animals, studying dark old newspapers to gather information on species ranging from aardvarks to koalas.
they noted that many female mammals release oxytocin and prolactin during sex: the hormones released by women during orgasms. What’s more, in many of these species, females use a type of reproduction that differs radically.
While women release an egg each month, other mammals female, such as rabbits and camels, release an egg only after mating with a male.
the ovulatory cycles evolved in just a few lineages of mammals, including ours, found Pavlicev and Wagner. Before that, our ancient ancestors mammals originally supported in an ovulation triggered by mating with a male.
These early mammals developed a clitoris inside the vagina. Only mammals that ovulatory cycles was developed the clitoris away. Based on these findings, Pavlicev and Wagner argue that female orgasm evolved primarily as a reflection to help females to get pregnant.
When the first humans mated, the clitoris could send signals to the brain, triggering hormones that released an egg. Once the fertilized egg was, hormones may have helped ensure that implanting in the uterus.
This arrangement has worked well for mammals rarely find males. It helps the females make the most of each copulation. But, eventually, some mammals, including primates like us, began to spend their lives in social groups. The females had access to regular sex with males and orgasm as ovulatory mechanism was no longer useful. Rather, our ancestors females evolved a new system: releasing eggs on a regular cycle. “I think we are seeing the entire reproductive system of women under a somewhat different light when you have a model for how it might have evolved,” he said.
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