Biologists have long puzzled about how evolutionary selection, known for its ruthless requirement for efficiency, allows the existence of males — when in so many species their only contribution to reproduction are spermatozoa.
But research published…in Nature shows that sexual selection — when males compete and females choose over reproduction — improves population health and protects against extinction, even in the face of genetic stress from high levels of inbreeding.
The findings help explain why sex persists as a dominant mechanism for reproducing offspring.
Lead researcher Prof Matt Gage, from UEA’s School of Biological Sciences, said: “Sexual selection was Darwin’s second great idea, explaining the evolution of a fascinating array of sights, sounds and smells that help in the struggle to reproduce — sometimes at the expense of survival.
“Sexual selection operates when males compete for reproduction and females choose, and the existence of two different sexes encourages these processes. It ultimately dictates who gets to reproduce their genes into the next generation — so it’s a widespread and very powerful evolutionary force.
“Almost all multicellular species on earth reproduce using sex, but its existence isn’t easy to explain because sex carries big burdens, the most obvious of which is that only half of your offspring — daughters — will actually produce offspring. Why should any species waste all that effort on sons?
“We wanted to understand how Darwinian selection can allow this widespread and seemingly wasteful reproductive system to persist, when a system where all individuals produce offspring without sex — as in all-female asexual populations — would be a far more effective route to reproduce greater numbers of offspring.
“Our research shows that competition among males for reproduction provides a really important benefit, because it improves the genetic health of populations. Sexual selection achieves this by acting as a filter to remove harmful genetic mutations, helping populations to flourish and avoid extinction in the long-term.”
Phew! Had me worried for a while. :)
RTFA for details of the analysis.
Hey – not any dumber than a contrived phrase like “erectile dysfunction”!
A daily dose of caffeine may reduce the odds of erectile dysfunction…Researchers analyzed dietary information to estimate the daily caffeine intake of 3,724 men who participated in the National Health and Nutrition Examination Survey.
The study…concluded that men may have a reduced risk for ED if they consume caffeine in daily doses roughly equivalent of two to three cups of coffee…per day.
Specifically, men who drank 171-303 mg of caffeine per day reduced the risk of ED by 39 percent and men who drank a daily 85-170 mg reduced the risk by 42 percent, while those who drank 7 mg or less per day reduced the risk by only 1 percent…
The study notes that the results constitute “no evidence for a trend” but adds that “these associations are warranted to be investigated in prospective studies.”
Terminology for polite society changes from generation to generation. It’s regional, often class-based and certainly governed by the quantity of so-called moral foolishness stuck into your mind.
I’m amazed at the number and quality of discoveries about the benefits of coffee-drinking popping up, nowadays. And glad I love my breakfast and brunchtime coffee.
The Consumer Electronics Show is in full swing in Las Vegas, which means editors’ inboxes are flooded with press releases about it.
Here at MedPage Today, we received one Monday that made us do a double-take. Well, one line in it, anyway.
The release, on behalf of “A&D Medical, the worldwide leader in connected health and biometric measurement devices, was about a survey of Americans’ attitudes on using smartphones and other “connected health devices that automatically connect online and send information to their doctor or other people they choose.”
We had just posted a story with a headline including the phrase “Smartphone in Bedroom Is Not So Smart Choice,” albeit for kids. Still, we were primed for some cognitive dissonance when we saw a line in the release saying that “And only 5% of Americans wanted their sexual activity monitored online.”
Really? We wondered whether “only” was really the right term there. We’re not PR experts, but we might have gone with something more like “More Americans want their sexual activity monitored online than voted for a third-party candidate in 2012.”
I must be out-of-date. I recall [in 1965] causing a disturbance in the middle of orientation for a group of activists when a pedant started listing distractions from strategic goals. He said something about food, where to eat in Chicago. He said something about sex.
I said “I don’t especially differentiate between the two…food and sex, that is.” Made some good friends on the West Side that day.
Now, I guess I need a new simile about smartphones and sex. I don’t think it works as well.
Intrauterine devices (IUDs) are amazingly, fantastically good at preventing pregnancy — better than pretty much any other available contraceptive.
Birth control pills, which have to be taken regularly — are susceptible to human error. The pill has a 6 percent failure rate. So out of 1,000 women taking birth control pills, 60 will become pregnant in a typical year. Among women who use an IUD, that number will be between 2 and 8 (depending on the type of IUD they use).
The American College of Obstetricians and Gynecologists recommends IUDs and the contraceptive implant (the one other long-acting, reversible contraceptive) as a “first-line” contraceptive that should be “encouraged as an option for most women.”
But despite IUDs’ incredible efficacy, few American women — just 8.5 percent of contraceptive-users — choose this method. The devices tend to get an especially bad rap in the United States because of the Dalkon Shield, an early IUD from the 1970s. It was hard to insert…sometimes failed to prevent pregnancy, injured as many as 200,000 women, and sometimes led to infertility or even death. All in all, it was a terrible contraceptive that was subsequently pulled from the market.
Today’s IUDs are different: they’re safer, easier to insert, and they work incredibly well. That probably explains why 40 percent of gynecologists using a contraceptive are using IUDs — way more than the general population…
RTFA. It’s long and really detailed. Lots of questions are answered – factually, reasonably, in human-speak.
Pretty useful article.
American women who work full time, year round are paid only 77 cents for every dollar paid to their male counterparts. But the wage gap is even larger for many women of color working full time, year round, as African-American women are paid only 64 cents, and Hispanic women only 54 cents, for every dollar paid to white, non-Hispanic men.
These gaps translated into a loss of $18,650 for African-American women and $24,111 for Hispanic women in 2012. Closing the wage gap is, therefore, particularly important for African-American and Hispanic women, who are already more likely to have lower incomes and to be in poverty than virtually all other groups.4 Although enforcement of the Equal Pay Act and other civil rights laws has helped narrow the wage gap over time, addressing the significant disparity that remains is critical for women and their families.
The wage gap for African-American and Hispanic women [.pdf] working full time, year round persists even when the effect of race or sex is considered alone.
• The typical African-American woman working full time, year round is paid roughly 83 cents for every dollar paid to her white, non-Hispanic female counterpart. The gap is larger for Hispanic women working full time, year round, who are paid just 69 cents for every dollar paid to their white, non-Hispanic female counterparts.
• The typical African-American woman working full time, year round is paid roughly 88 cents for every
dollar paid to her African-American male counterpart. The gap is the same for Hispanic women working full time, year round, who are also paid 88 cents for every dollar paid to their Hispanic male counterparts.
RTFA for example after example of death by a thousand cuts if you ain’t white and male.
Not so incidentally, if you are white and male don’t get smug. Although you may not have confronted pay cuts directly, part of the discrimination that adds to profit – is that white men also receive less than they might because “Hey, look. You’re better off than they are, eh?” And that’s good enough for plenty of guys who haven’t looked at what they might be earning if they got together and joined forces with the rest of their class.
“Chimp leader assassinated by gang of underlings,” read the headline last year in New Scientist. It told the story of Pimu, who led his cohort of chimpanzees until a violent day in March last year when Pimu picked the wrong fight. Four chimpanzees appeared out of nowhere, according to New Scientist, and beat Pimu to death with their hands and feet. It was a grisly end for a species that, along with humans, are among the only animals to coordinate attacks on their own kind.
But such a murder was a natural action, according to a study published Wednesday in Nature. The paper, which analyzed data from 426 combined years of observation and 18 separate chimp sites, argues chimps are not driven to violence by their contacts with humans, which some scientists have previously contended. Chimps, rather, are natural born killers.
“Variation in killing rates was unrelated to measures of human impacts,” said the paper, which was researched by an international team of 30 scientists. “… The adaptive strategies hypothesis views killing as an evolved tactic by which killers tend to increase their fitness through increased access to territory, food, mates and other benefits…”
The rate of killing…seems more dependent on how many males were in each band of chimps as well as population density. It’s inter-community tension — not outer-community tension.
Just as chimps appear to reflect some humanity’s better traits, they also reflect the bad…anthropologist Joan Silk wrote in an accompanying article.
“The behavior of non-human primates, particularly chimpanzees, are often distorted by ideology and anthropomorphism, which produce a predisposition to believe that morally desirable features, such as empathy and altruism, have deep evolutionary roots, whereas undesirable features, such as group-level violence and sexual coercion, do not,” she wrote. “This reflects a naive form of biological determinism.”
Steps in the evolutionary ladder are not as far apart as some would presume. That is, those members of human society whose understanding of life on this planet extends beyond the 14th Century.
The rest, sad to say, still rely on wee winged creatures sitting on either shoulder whispering in their ears.
Scientists continue to unveil impressive innovations at the American Chemical Society’s annual conference, currently being held in San Francisco. The latest is a removable tattoo that doubles as a miniature battery — turning human sweat into storable electricity.
The device is meant to be worn during a trip to the gym. It can monitor a person’s progress during exercise routines while simultaneously powering a small electronic device, like an iPod.
The mini tattoo tracks athletic performance by measuring levels of lactate in sweat secreted by the exerciser…
Currently, lactate testing is done via blood samples. But by installing a lactate sensor in a temporary tattoo, researchers found a way to track performance in a much less evasive way. They also found a way to produce electricity. As the sensor processes the lactate in the sweat, it strips the lactate of electrons.
Engineers designed the sensor so it could pass the stripped electrons from an anode to a cathode, just like a battery.
UC nanoengineering professor Dr. Joseph Wang said the device is “the first example of a biofuel cell that harvests energy from body fluid.”
There must be some way to make money from sex – using this discovery.
A Japanese artist who made figures of Lady Gaga and a kayak modeled on her vagina said on Wednesday from jail she was “outraged” by her arrest and vowed a court fight against obscenity charges.
Megumi Igarashi, 42, says she was challenging a culture of “discrimination” against discussion of the vagina in Japanese society.
Igarashi, who worked under the alias Rokudenashiko, which means “good-for-nothing girl” in Japanese, built a yellow kayak with a top shaped like her vagina after raising about $10,000 through crowdfunding.
Igarashi sent 3D printer data of her scanned vagina – the digital basis for her kayak project – as a thanks to a number of donors.
She was arrested for distributing indecent material on Saturday and faces up to two years in prison and a fine of up to $25,000.
Igarashi said about 10 police officers had arrived at her house on Saturday and initially, she thought they were only interested in confiscating work she has said is meant as a pop-art exploration of the “manko”, vulgar Japanese slang for vagina.
“I couldn’t stop myself from laughing a little as I explained to the grim-looking officers, ‘This is the Lady Gaga ‘manko’ figure’,” Igarashi told Reuters from across a plastic security divide in a central Tokyo jail.
“I did not expect to get arrested at all. Even as they were confiscating my works, I thought to myself, ‘This will be a good story’. Then they handcuffed and arrested me. Now, I just feel outraged…”
Igarashi has touched off a debate on both women’s rights and the freedom of artistic expression, said Kazuyuki Minami, her lead defense lawyer.
The legal definition of what counts as obscenity is vague in Japan, and the key point of debate will be deciding whether the vagina itself can be considered obscene, said Minami…
A 1951 Supreme Court case broadly defined obscenity as something that stimulates desire and violates an ordinary person’s sense of sexual shame and morality.
Just like political idjits, bigoted idjits, even musical idjits – every nation seems to have its share of sensual and sexual idjits. Japan, obviously, is no exception.