5 Signs Humans Are Still Evolving

Lealisa Westerhoff, AFP/Getty Images
Lealisa Westerhoff, AFP/Getty Images

When we think of human evolution, our minds wander back to the millions of years it took natural selection to produce modern-day man. Recent research suggests that, despite modern technology and industrialization, humans continue to evolve. "It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans," Dr. Virpi Lummaa, a professor at the University of Turku, told Gizmodo.

But not only are we still evolving, we're doing so even faster than before. In the last 10,000 years, the pace of our evolution has sped up, creating more mutations in our genes, and more natural selections from those mutations. Here are some clues that show humans are continuing to evolve.

1. Humans drink milk.

Historically, the gene that regulated humans' ability to digest lactose shut down as we were weaned off our mothers' breast milk. But when we began domesticating cows, sheep, and goats, being able to drink milk became a nutritionally advantageous quality, and people with the genetic mutation that allowed them to digest lactose were better able to propagate their genes.

The gene was first identified in 2002 in a population of northern Europeans that lived between 6000 and 5000 years ago. The genetic mutation for digesting milk is now carried by more than 95 percent of northern European descendants. In addition, a 2006 study suggests this tolerance for lactose developed again, independently of the European population, 3000 years ago in East Africa.

2. We're losing our wisdom teeth.

Our ancestors had much bigger jaws than we do, which helped them chew a tough diet of roots, nuts, and leaves. And what meat they ate they tore apart with their teeth, all of which led to worn-down chompers that needed replacing. Enter the wisdom teeth: A third set of molars is believed to be the evolutionary answer to accommodate our ancestors' eating habits.

Today, we have utensils to cut our food. Our meals are softer and easier to chew, and our jaws are much smaller, which is why wisdom teeth are often impacted when they come in — there just isn't room for them. Unlike the appendix, wisdom teeth have become vestigial organs. One estimate says 35 percent of the population is born without wisdom teeth, and some say they may disappear altogether.

3. We're resisting infectious diseases.

In 2007, a group of researchers looking for signs of recent evolution identified 1800 genes that have only become prevalent in humans in the last 40,000 years, many of which are devoted to fighting infectious diseases like malaria. More than a dozen new genetic variants for fighting malaria are spreading rapidly among Africans. Another study found that natural selection has favored city-dwellers. Living in cities has produced a genetic variant that allows us to be more resistant to diseases like tuberculosis and leprosy. "This seems to be an elegant example of evolution in action," says Dr. Ian Barnes, an evolutionary biologist at London's Natural History Museum, said in 2010 statement. "It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force."

4. Our brains are shrinking.

While we may like to believe our big brains make us smarter than the rest of the animal world, our brains have actually been shrinking over the last 30,000 years. The average volume of the human brain has decreased from 1500 cubic centimeters to 1350 cubic centimeters, which is an amount equivalent to the size of a tennis ball.

There are several different conclusions as to why this is: One group of researchers suspects our shrinking brains mean we are in fact getting dumber. Historically, brain size decreased as societies became larger and more complex, suggesting that the safety net of modern society negated the correlation between intelligence and survival. But another, more encouraging theory says our brains are shrinking not because we're getting dumber, but because smaller brains are more efficient. This theory suggests that, as they shrink, our brains are being rewired to work faster but take up less room. There's also a theory that smaller brains are an evolutionary advantage because they make us less aggressive beings, allowing us to work together to solve problems, rather than tear each other to shreds.

5. Some of us have blue eyes.

Originally, we all had brown eyes. But about 10,000 years ago, someone who lived near the Black Sea developed a genetic mutation that turned brown eyes blue. While the reason blue eyes have persisted remains a bit of a mystery, one theory is that they act as a sort of paternity test. “There is strong evolutionary pressure for a man not to invest his paternal resources in another man’s child,” Bruno Laeng, lead author of a 2006 study on the development of blue eyes, told The New York Times. Because it is virtually impossible for two blue-eyed mates to create a brown-eyed baby, our blue-eyed male ancestors may have sought out blue-eyed mates as a way of ensuring fidelity. This would partially explain why, in a recent study, blue-eyed men rated blue-eyed women as more attractive compared to brown-eyed women, whereas females and brown-eyed men expressed no preference.

Here’s What You Need to Know About the New Coronavirus

jarun011/iStock via Getty Images
jarun011/iStock via Getty Images

This morning, the Centers for Disease Control and Prevention (CDC) confirmed the second case of the recently discovered coronavirus in the U.S. Find out what it is, where it is, how to avoid it, and all the other need-to-know information about the illness below.

What is the new coronavirus?

Coronaviruses are a group of viruses named for the crown-shaped spikes that cover their surfaces (corona is the Latin word for crown). According to the CDC, human coronaviruses can cause upper-respiratory tract illnesses, including the common cold, and can sometimes lead to more severe lower-respiratory tract issues like pneumonia or bronchitis.

Because this latest coronavirus, 2019-nCoV, is so new, health officials are currently trying to figure out how it works and how to treat it. It’s not the first time a potent new coronavirus has caused an international outbreak: SARS-CoV originated in Asia and spread to more than two dozen countries in 2003, and MERS-CoV first infected people in Saudi Arabia before spreading across the globe in 2012.

Where is the coronavirus outbreak happening?

The majority of cases are in China, which counts more than 800 confirmed diagnoses. Most are in Wuhan, a city in China’s Hubei province where 2019-nCoV was first detected last month. Additional cases have been reported in South Korea, Japan, Singapore, Hong Kong, Macao, Taiwan, Thailand, and Vietnam.

The CDC has confirmed two U.S. cases—a man in his thirties outside Seattle, and a 60-year-old woman in Chicago—both of whom had recently returned from trips to Wuhan. A CDC official said another 63 potential cases are being investigated in 22 states, and airports in New York, Chicago, Los Angeles, Atlanta, and San Francisco are conducting health screenings on passengers arriving from China.

Chinese officials have shut down transportation to and from Wuhan. Tourist spots like Beijing’s Forbidden City, Shanghai Disneyland, and a portion of the Great Wall are also closed temporarily.

What are the symptoms of the new coronavirus?

Symptoms are similar to those caused by a cold or the flu, including fever, dry cough, and breathing difficulty. The New York Times reported that as of Friday morning, 25 people in China have died from the virus, and most of them were older men with preexisting health conditions like cirrhosis, diabetes, and Parkinson’s disease.

How does the new coronavirus spread?

Because most of the early cases of 2019-nCoV were traced back to a seafood and meat market in Wuhan, health officials think the virus originally spread from infected animals to humans, but it’s now being transmitted from person to person.

Though scientists are still studying exactly how that happens, the leading theory is that it travels in tiny droplets of fluid from the respiratory tract when a person coughs or sneezes.

How do you avoid the new coronavirus?

The CDC is warning everyone to avoid any nonessential trips to Wuhan, and to avoid animals or sick people if you’re traveling elsewhere in China. If you’ve been to China in the last two weeks and experience any of the symptoms listed above, you should seek medical attention immediately—and you should call the doctor’s office or emergency room beforehand to let them know you’re coming.

Otherwise, simply stick to the precautions you’d normally take when trying to stay healthy: Wash your hands often with soap and water, cover your nose and mouth when coughing or sneezing, stay away from sick people, and thoroughly cook any meat or eggs before eating them.

Should you be worried about the new coronavirus?

The global health community is taking 2019-nCoV seriously in order to curb the outbreak as quickly as possible, but you shouldn’t panic. The CDC maintains that it’s a low-risk situation in the U.S., and public health officials are echoing that message.

“We don’t want the American public to be worried about this, because their risk is low,” Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told USA Today.

[h/t USA Today]

Has An Element Ever Been Removed From the Periodic Table?

lucadp/iStock via Getty Images
lucadp/iStock via Getty Images

Barry Gehm:

Yes, didymium, or Di. It was discovered by Carl Mosander in 1841, and he named it didymium from the Greek word didymos, meaning twin, because it was almost identical to lanthanum in its properties. In 1879, a French chemist showed that Mosander’s didymium contained samarium as well as an unknown element. In 1885, Carl von Weisbach showed that the unknown element was actually two elements, which he isolated and named praseodidymium and neodidymium (although the di syllable was soon dropped). Ironically, the twin turned out to be twins.

The term didymium filter is still used to refer to welding glasses colored with a mixture of neodymium and praseodymium oxides.

One might cite as other examples various claims to have created/discovered synthetic elements. Probably the best example of this would be masurium (element 43), which a team of German chemists claimed to have discovered in columbium (now known as niobium) ore in 1925. The claim was controversial and other workers could not replicate it, but some literature from the period does list it among the elements.

In 1936, Emilio Segrè and Carlo Perrier isolated element 43 from molybdenum foil that had been used in a cyclotron; they named it technetium. Even the longest-lived isotopes of technetium have a short half-life by geological standards (millions of years) and it has only ever been found naturally in minute traces as a product of spontaneous uranium fission. For this reason, the original claim of discovery (as masurium) is almost universally regarded as erroneous.

As far as I know, in none of these cases with synthetic elements has anyone actually produced a quantity of the element that one could see and weigh that later turned out not to be an element, in contrast to the case with didymium. (In the case of masurium, for instance, the only evidence of its existence was a faint x-ray signal at a specific wavelength.)

This post originally appeared on Quora. Click here to view.

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