Hot, Humid Weather May Have Helped Shape Human Noses


Noses may be the unsung heroes of the face. We tend to think of them as mere scent collectors, but noses do so much more, including make it possible for humans to survive in different climates all over the world. A study published in the American Journal of Physical Anthropology explores how that may have come about.

Your nose acts like a portable, personal HVAC system, treating the air you inhale to make it easier for your body to process. In the winter, your nose warms the air so that it’s nice and toasty by the time it reaches your lungs. In arid climates, our noses add humidity to our inhalations to keep our respiratory tracts from drying out.

Human nose shape, like skin color, generally varies by latitude. Scientists have suggested that northern Europeans’ thin, pointy noses evolved to help their ancestors process their homelands’ cold, dry air, since narrow nasal passages mean that a greater percentage of inhaled air has to come into contact with heat- and moisture-adding mucous membranes. This, the researchers believed, was the only way the nose has evolved: away from the flatter, wider noses of people living closer to the Equator. The air in those regions is typically hot and humid already, requiring no special treatment. So if the winter nose is a custom job, they said, the summer nose must be the base model.

But "we don't really think that that's true," said biological anthropologist Scott Maddux of the University of North Texas Health Science Center. Maddux and his team used global climate data from 1901 to 2013 to construct maps of average annual temperature and humidity. Then, they compared those with the results of a study from 1923, which measured the noses of more than 15,000 people from 147 countries.

Their results suggest that, rather than a starting point, wider, flatter noses have themselves evolved to help their owners cope in those hot, muggy climates. Humidity is rough on the human body. It makes it much harder for us to shed heat by sweating, so we have to find other ways to cope. One way to do that might be allowing more heat to escape through the two holes in the middle of our face. The wider the nose, the more heat it can funnel out of the body. 

More questions remain. Nearly all the work our noses do takes place inside in a part called the nasal cavity. If it’s the cavity that’s doing the heating and humidifying, Maddux says, why would the outside of our noses need to change at all? To find out, scientists will need to go deeper inside, all the way to our skulls.

Nicholas Holton, a biological anthropologist at the University of Iowa, was not involved in the study but praised the team’s work. "A big part of any face, not just the human face, is the nose," he told Inside Science. "Literally, it's a central component of the skull, so understanding what's happening with the nose may tell us a lot about what's happening with the rest of the face."

[h/t Inside Science]

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Courtesy of October Films
This Scientist's Idea of the 'Perfect' Human Body Is Kind of Terrifying
Courtesy of October Films
Courtesy of October Films

The perfect human body has the legs of an ostrich, the heart of a dog, and the eyes of an octopus, according to anatomist Alice Roberts. And it’s utterly terrifying.

With the help of anatomical artist Scott Eaton and special effects designer Sangeet Prabhaker, Roberts created a life-size replica of herself that fixes many design flaws inherent to the human body, Motherboard reports. Roberts unveiled the sculpture on April 23 at the Science Museum in London. On June 13, the BBC released a documentary about the project.

Among the flaws Roberts’s sculpture corrects are humans’ inferior ears, spine, and lungs. Roberts borrowed anatomy from reptiles, birds, and other mammals to create a Frankenstein-esque creature straight from the island of Dr. Moreau.

The sculpture of Alice 2.0, left, with Alice Roberts, right
Courtesy of October Films

The sculpture has legs like an ostrich because, as Roberts says on her website, the human knee is complex and prone to failure. Like humans, ostriches are bipedal, but they are far better runners. Bird-like lungs that keep air flowing in one direction, not two, make running and other aerobic activities easier for the perfect human to manage. And a chimpanzee’s sturdier spine and a dog’s heart (which has more connected arteries, leading to lower heart attack risk) make Roberts’s alternate self more resistant to injury and disease.

Roberts’s ideal human body also has skin like a frog that can change shades based on the environment, and large, bat-like ears that amplify sound. Roberts also fixed humans’ backwards retina, which produces a natural blind spot, by borrowing from octopus eye anatomy.

Perhaps most disturbing of all is the baby head poking out of the sculpture’s marsupial pouch. Roberts says marsupial pregnancy would be far easier on the human body and more convenient for parents on the go.

“This could be a human fit for the future,” Roberts says at the end of a trailer for her BBC documentary.

[h/t Motherboard]

Scientists Accidentally Make Plastic-Eating Bacteria Even More Efficient

In 2016, Japanese researchers discovered a type of bacteria that eats non-biodegradable plastic. The organism, named Ideonella sakaiensis, can break down a thumbnail-sized flake of polyethylene terephthalate (PET), the type of plastic used for beverage bottles, in just six weeks. Now, The Guardian reports that an international team of scientists has engineered a mutant version of the plastic-munching bacteria that's 20 percent more efficient.

Researchers from the U.S. Department of Energy's National Renewable Energy Laboratory and the University of Portsmouth in the UK didn't originally set out to produce a super-powered version of the bacteria. Rather, they just wanted a better understanding of how it evolved. PET started appearing in landfills only within the last 80 years, which means that I. sakaiensis must have evolved very recently.

The microbe uses an enzyme called PETase to break down the plastic it consumes. The structure of the enzyme is similar to the one used by some bacteria to digest cutin, a natural protective coating that grows on plants. As the scientists write in their study published in the journal Proceedings of the National Academy of Sciences, they hoped to get a clearer picture of how the new mechanism evolved by tweaking the enzyme in the lab.

What they got instead was a mutant enzyme that degrades plastic even faster than the naturally occurring one. The improvement isn't especially dramatic—the enzyme still takes a few days to start the digestion process—but it shows that I. sakaiensis holds even more potential than previously expected.

"What we've learned is that PETase is not yet fully optimized to degrade PET—and now that we've shown this, it's time to apply the tools of protein engineering and evolution to continue to improve it," study coauthor Gregg Beckham said in a press statement.

The planet's plastic problem is only growing worse. According to a study published in 2017, humans have produced a total of 9 billion tons of plastic in less than a century. Of that number, only 9 percent of it is recycled, 12 percent is incinerated, and 79 percent is sent to landfills. By 2050, scientists predict that we'll have created 13 billion tons of plastic waste.

When left alone, PET takes centuries to break down, but the plastic-eating microbes could be the key to ridding it from the environment in a quick and safe way. The researchers believe that PETase could be turned into super-fast enzymes that thrives in extreme temperatures where plastic softens and become easier to break down. They've already filed a patent for the first mutant version of the enzyme.

[h/t The Guardian]


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