On October 19th, 2017 we learned about

New evidence necessitates the reevaluation of species that survived past their supposed extinctions

It seems like it’d be hard to miss an animal the size of a lion named for its serrated, sword-like teeth. An animal like Homotherium latidens, or the European scimitar cat, was once one of Europe’s most formidable predators, at least until 300,000 years ago, when it seemed to have gone extinct. However, a jawbone pulled from the North Sea is rewriting that timeline by 270,000 years, as both carbon dating and genetic evidence suggests it was alive as recently as 28,000 years ago. This younger specimen is now raising a lot of questions, as new causes for extinction, new ecological niches and that giant gap in the fossil record all need to be reconsidered.

Homotherium were like slightly scaled-down versions of their more famous saber-toothed cousins, like Smilodon. Nonetheless, this cat still had two large, canine teeth, and their knife-edge shapes suggest they were probably used for cutting and slashing rather than simply impaling prey. It’s hard to know for sure, because the humans that we now know lived as neighbors to these scimitar cats unfortunately didn’t leave any good field notes behind. Even cave paintings of predatory cats found in norther France somehow omit any solid portraits of H. latidens.

Missing, or migrating?

One of the possible explanations for Homotherium’s absence in the fossil and written record may be that they just weren’t around much. One hypothesis to explain how the cats could be alive without leaving behind more evidence is that they had gone on a very long migration, possibly even around the world. This idea is slightly bolstered by some the fact that the cats’ closest relatives are known to have turned up in North America, although that relationship is also being reexamined.

Looking at the mitochondrial DNA recovered from the new jawbone, researchers were able to not only date the specimen, but also see where it fits in the larger cat family tree. They found that H. latidens is remarkably similar to its North American kin, Homotherium serum— so much so that it’s been suggested that they might be the same species in a new location. This similarity is in contrast to H. latidens’ relationship with other cat species, which forked away from each other 20 million years ago. While they do share a common ancestor, your house cat is more closely related to a modern tiger than Homotherium is to other saber-toothed cats like Smilodon.

Assuming that we’ve now found the most recent H. latidens bone on the planet, scientists now have to think about what caused its final extinction 28,000 years ago. As presumptuous as it sounds, there’s a fair chance that these cats really did go extinct at that point (really!) if only because so many other animals were being removed from the food chain around the same time. Europe was experiencing an ice age at that point and coming to grips with more efficient human hunters. The combined ecological stresses likely explain not only the extinction of these saber-toothed cats, but other megafauna like mammoths and cave bears as well.

Other exaggerated extinctions

Balbaroo fangaroo
Balbaroo fangaroo, who’s name may never be topped

As big an upheaval as this new bone has caused, it’s worth remembering that this isn’t the first time paleontologists have had to rethink extinctions. You can’t predict what fossils will be found, and while most species seem to cluster geographically and chronologically, they can surprise us with their extended survival. Just this month, another extinct mammal with big teeth extended it’s timeline, but by five million years. Fanged kangaroos like Balbaroo fangaroo weren’t exactly impressive predators, as they were browsing herbivores that scurried around ancient Australia, but they apparently did better than we’d previously given them credit for. Like the European saber-toothed cats, the pressures that drove them to their (final!) extinction is now be rethought, since in their case they seem to have outlived their regions major climate crisis known to have taken place 15 million years ago.

Source: This Saber-Toothed Cat Mingled With Modern Humans by Michelle Z. Donahue, National Geographic

On October 19th, 2017 we learned about

Frozen pee may be a practical reference point in our future search for life on Enceladus

In 2005, the Cassini spacecraft captured images of plumes of icy water erupting from Saturn’s moon, Enceladus. Subsequent flybys and sampling have suggested that this moon may be habitable by some form of life in its sub-surface ocean, thanks to geological heating. However, this is all inconclusive at this point, because Cassini wasn’t designed to tackle this kind of mission. Even when the spacecraft was flown through the moon’s icy geysers, it could only sample a limited portion of the ejected slush, since the probe could only detect one size of ice grain at a time. Now that Cassini has been crashed into Saturn, researchers are hoping to get another probe to Enceladus, but they need to make sure it’s ready for the job, and that means developing a better understanding of frozen water when it’s flushed into space.

In better tailor sensors for the icy ejecta of Enceladus, engineers would like experiment with, or at least observe, water as it flows into the cold vacuum of space. Of course, water is heavy and therefore expensive to get off the ground, plus astronauts value it as a way to stay, you know, alive. So rather than fly water up to space only to toss it out, it’s been proposed that we start paying closer attention to how wastewater from astronauts’ toilets as well as fuel cells, behaves when it’s vented from spaceships. Wastewater, or any water, spewed from a small metal tube wouldn’t be a perfect proxy for the vents of Enceladus, but it may be a starting point for measuring what kind if ice crystal distribution should be expected.

Previous work with purged pee

There’s also some precedent for these observations. In 1989, researchers used a telescope in Hawaii to watch as the space shuttle Discovery dumped water from its fuel cells. They couldn’t develop a full 3D model from these observations, but they could at least note that two sizes of ice grain formed. Bigger pieces of ice formed right out of the vent, while smaller grains, probably from recondensed water vapor, formed further away. The space shuttles also ejected liquid waste while on missions, although they made sure to keep the astronauts poop for later disposal back on Earth. Some of this vented liquid was found to form long icicles just outside the vents, suggesting another phenomenon that could be found on Enceladus.

While space shuttles dumped liquids more often, the International Space Station doesn’t quite provide the same opportunities to observe frozen pee. Pee isn’t sprayed into space as much anymore, partially due to the realization that frozen urine ejected from the Mir space station in the late 1980s had been slowly damaging the facility’s solar panels. Instead, most of the astronauts’ pee is cleaned and recycled into drinking water, leaving only the most concentrated, briny, urea to be purged into space. Astronauts’ poop doesn’t get tossed out either, but is instead packaged with other bundles of trash that are dropped into the natural incinerator that is the Earth’s atmosphere.

With these limitations, it’s not clear how much we’ll learn by watching astronaut’s waste water. At the very least, the stuff humans flush can at least provide a basic reference point for what to expect the next time we’re near Enceladus.

Source: Astronaut wee could show us how the plumes on Enceladus work by Leah Crane, New Scientist

On October 18th, 2017 we learned about

Tactile stealth makes mosquitoes more successful at sucking your blood

In addition to keeping your guts in, germs out and providing a convenient canvas for tattoos and scars, your skin is your body’s largest sensory organ. It’s loaded with different types of nerve cells to pick up tiny changes in pressure that might spell trouble for your body, from a cactus needle to a parasitic insect. Unfortunately for us, insects like mosquitoes have evolved adaptions to our epidermal warning system, giving them a chance to sneak in a bloody snack without drawing our attention.

Sneaky stabbing and sucking

When a mosquito “bites” you, it’s actually piercing your skin with its proboscis. In insects like butterflies, the proboscis is a long, delicate tube that is used to suck up nectar from a flower. In a mosquito, it’s a bit more weaponized, and is actually a sheathed set of six thin needles called stylets. Two stylets have tiny teeth to cut through the skin, but they’re sharp enough that they can slip between your skin’s sensory defenses. The next two stylets push the incision open, followed by a labrum that senses for blood vessels.

Finally, the hypopharynx covers the top of the labrum to make it into more of a tube, as well as drip drool back into your incision. In addition to passing pathogens to our bodies, the drool keeps the blood from coagulating, or clotting, too quickly. This allows the mosquito to get her fill of blood cells, even taking the time to poop out excess water while she sucks.

Soft, delicate departures

A mosquitoes departure is no less specialized, as all that blood would go to waste if we detected the parasite and squashed before it could escape to lay eggs. Many insects, and birds and probably pterosaurs, kick-start their flight by pushing off the ground, or skin, with their legs. By catapulting themselves into the air, they save their wings some work and get moving faster. The catch is that they’re exerting all the force of their liftoff in one quick movement, which means that that force feels more punctuated and noticeable to your skin.

To make their departure as gentle and subtle as possible, mosquitoes shift the work to their wings. 61 percent of a mosquitoes liftoff is powered by its wings, which get to push against the air instead of your skin. Their longer legs than the average fly allow them to push with the same amount of force, but that force can be spread out over a longer amount of time. All these adjustments soften the impact of mosquito take-offs, but without sacrificing speed compared to other flies. The one catch is that a belly full of blood does weigh them down a bit, as they move around 18 percent slower in the air than unladen insects. This means a mosquito’s final escape is just less than one mile an hour, although we’re usually too distracted by the histamine-induced itching to notice.

Source: The physics of mosquito takeoffs shows why you don’t feel a thing by Mariah Quintanilla, Science News

On October 18th, 2017 we learned about

STEM students can, and probably should, do a bit of dancing

When my wife was a graduate student, she helped run a dance troupe, took ballet classes, and performed and help produce a campus-wide dance show. The program ran over an hour, featuring everything from hula to ballroom, lyrical to… something approximating hip-hop. These performers probably weren’t going to give up their day jobs, but they all looked pretty amazing considering their day jobs had them working in some of the world’s most prestigious research labs across a huge range of fields. Nobody questioned the value of dance in these scientists’ lives, and the school community was very supportive of the show each year. A more formalized study from North Carolina State University has come to similar, if more specific conclusions. Even top-notch biochemists benefit from time on the dance floor.

Finding balance with ballet or ballroom

The study was framed against the multitude of calls for more science, technology, engineering and mathematics (STEM) education in the United States. As technology continues to shape our economies and capabilities, STEM proponents feel that students need to be more thoroughly prepared to have an active role in those fields, or else risk falling behind. However, focus shouldn’t mean ignoring other activities, and it seems that students from all disciplines, including STEM, can improve their lives by participating in creative arts like a dance troupe or class.

The pattern that emerged through surveys and interviews was that dance was both complementary and supplementary to academic work. Rehearsing a specific dance for a class or possible performance requires, and reinforces, self-discipline that is crucial for any form of research. Students reported dance helped them work with larger groups, and it was easier to incorporate multiple viewpoints into their thinking. Of course, it doesn’t hurt that dance can be fun, allowing for personal expression and a sense of community, all without the need for a keg of beer. Researchers hope to follow up with a more quantifiable study, looking at how participating in dance affects work performance and personal health.

Mental challenges of choreographed movement

Beyond proving the value of dance in STEM-oriented environments, many previous studies have looked at how dance can benefit individual brains. The rhythmic movement has been found to trigger reward centers, which are further boosted by the accompanying music during a performance. Coordinated efforts in choreographed and spontaneous dance have been found to increase activity in the motor cortex, somatosensory cortex, basal ganglia, and cerebellum, all in order to handle planning, control and movement of the body. Some of this is likely true for other physical activities as well, but in a 2003 study, only dance classes were found to help lower participants’ risk of developing dementia. This is thought to be tied to some of the social aspects of dance that isn’t replicated in a game of golf, for instance.

Where does all this lead us? To Dance Your PhD, of course.

Source: How Dance Can Help Students in STEM Disciplines by Fay Cobb Payton and Matt Shipman, NC State News

On October 17th, 2017 we learned about

A history of air pollution recorded on preserved bird bellies

History is usually studied in written records, man-made objects, rocks and bones. It’s no surprise that we generally rely on durable materials like this, but more studies of more recent history aren’t so limited. Thanks to careful preservation of biological samples from around 200 years ago, we can use softer, more delicate bits of biology to find out what was happening in the world, including picking up evidence of very indelible events, like air pollution from the industrial revolution. In that case, instead of looking at stone or tools, researched dug into museum collections to survey thousands of dead, but preserved, birds.

By the 1870s, parts of the United States were being overwhelmed by smoke from furnaces and steam engines. These early combustion engines opened up a lot of new possibilities in technology, but they also dumped a lot of soot on their surrounding neighborhoods. By 1874, places like Chicago were so choked with smoke that it obscured the Sun on a daily basis, a scenario we usually associate with natural disasters. These smokey years have been documented in some forms, but biologists wanted to find data on air pollution across a wider territory and time span. The record they then turned to was the accumulated soot that was still stuck to the feathers of birds collected from the 1800s to the present day.

Documenting accumulated dirt

The researchers traveled to museums around America’s so-called Rust Belt to compare as birds across different decades and locales. Instead of taking samples of soot for chemical analysis, they measured the overall level of contamination on a bird’s body by taking photos, then quantifying exactly how dark its white feathers had become. To make sure varying light levels or human error didn’t throw off these measurements, each bird was placed next to a paint strip called a reflectance that allowed each photo to be properly calibrated, ensuring that the gray on a woodpecker or horned lark’s belly was the result of smoke and not a shadow. Once the data was gathered, it was plotted by location and time frame, revealing the history of America’s air quality with impressive specificity.

The dirtiest birds were dated from the beginning of the 20th century, when industrial air pollution was at its peak. Feathers were cleaner when manufacturing declined during the Great Depression, and were then dirtier again during World War II. Birds after the 1955 Air Pollution Control Act looked cleaner than their predecessors, and those that had lived after 1963’s Clean Air Act were cleaner still. When he birds were laid next to each other, the gradation was obvious enough that my four- and eight-year-old immediately picked up on it. My eight-year-old also commented that the dirtier birds were generally smaller as well. Unfortunately, the effects this soot might have had on the birds (ruling out age or other nutritional differences) wasn’t in the study’s scope.

Bird breathing problems

Other studies, however, have looked at the effects on air pollution on our feathered friends, even before they’re covered in soot. Beyond canaries in coal mines, birds’ health has been found to decline from air pollutants faster than humans, as pollutants often lead to thinner egg shells and lower birth rates. Relative body sizes probably play a role, but scientists suspect that bird respiration also contributes to their sensitivity to particulate in the air. While humans breath in and out in two distinct steps, birds breath in a more continuous cycle, essentially inhaling and exhaling in one step. This allows them to fuel the metabolism needed for high-energy tasks like flying without pumping their lungs as a ridiculous rate. It unfortunately also means that they’re more efficient at sucking in soot and other toxins that can cause health problems. So if the birds are suffering in an area, there’s a chance that human health is being attacked as well. Or to put it in a more positive light, you can breath easy if your avian neighbors are clean and in good health.

Source: Sooty Feathers Tell the History of Pollution in American Cities by Alex Furuya, Audubon

On October 17th, 2017 we learned about

Optimistic findings about preventing fires by reducing the amount of flammable fuel in forests

With yet another wildfire filling our skies with smoke, it’s starting to feel like California will never stop burning. The state experienced an unusually rainy winter that thankfully helped fend off a multi-year drought, spurring new plant growth at the same time. Unfortunately, all that vegetation was dried out in record-setting summer heat. From that perspective these fires feel somewhat inevitable, since we can’t stop the rain and many people in power seem intent on avoiding doing much to curb climate emissions that help make more extreme temperatures. However, there’s still opportunities to reduce our fire risks by thinning out the forests themselves, either mechanically or with controlled burns. These aren’t easy tasks to take on, but studies suggest that strategic thinning may reduce some of the costs and logistics associated with wildfire prevention.

For millions of years, forests have occasionally caught fire. In this time, they’ve adapted to make the most of blazes naturally caused by things like lightning strikes, in some cases even evolving pine cones that only open in a fire’s extreme heat. Humans have thrown this balancing act off a bit though, as we both help start fires more often with sparking cars, campfires and cigarettes, but also rush to put those fires out as soon as possible. The result is that forests are now denser than before, not just with living plants but also dry, dead branches, pine needles and more. This means that when a fire does start up, it’s got a lot more fuel to burn, and can get out of control much more quickly.

Small burns aren’t bad

A controlled burn certainly works, because it’s intended to be a safer version of a good lightning strike. Burning a small area ideally clears out dry tinder, but can then be contained before it becomes a problem. Detractors to this method have worried about the fires getting out of control, but also about unintended damage to the environment. To see if prescribed burns were harming plants or animals, the U.S. Forest Service and six universities embarked on detailed studies of the flames’ effects on the affected environment. While there’s obviously smoke and soot after a burn, a smaller fire caused no measurable harm. If anything, plant diversity increased and trees seemed more resilient to things like bark beetles after a small fire. This makes sense, because the more frequent fires of the past would have been smaller on average, and thus something these ecosystems have been able to adapt to.

Mechanical thinning, for less money

Mechanical thinning doesn’t risk running out of control like a fire, and aside from some diesel exhaust, shouldn’t introduce widespread threats to the environment. Instead, detractors bring up the prices and logistics of sending in personnel to clear brush and remove trees, as it can become a huge task in a large forest. Real world experiments were, appropriately, cost prohibitive, so biologists from the University of New Mexico ran simulations of two approaches to mechanical thinning. One option tested the effectiveness thinning vast ranges of land, while the other looked at scenarios where only areas that were considered to be higher risk were dealt with. With all other things being equal, both strategies reduced the severity of simulated fires by as much as 60 percent. This may sound inconclusive until you compare the difficulty of either approach, and realize that the much simpler, cheaper option of thinning only high-risk areas of a forest offers the same benefits for a much smaller price. This means that well-planned mechanical thinning may be more affordable than people previously understood.

If these last two weeks are anything to go by, it looks like we’ll unfortunately have ample opportunities to put these prevention methods to work in the coming years.

Source: Fighting Fires Before They Spark, Scienmag

On October 16th, 2017 we learned about

Currency made from fruit bat teeth offers an opportunity for conservation

How much is a tooth worth? It probably depends on who you ask. A tooth that needs saving at the dentist can get pretty pricey, while a baby tooth that falls out might net around a dollar from the tooth fairy. For mammals like giant fruit bats living in the Solomon Islands, a mouth full of teeth may cost them their lives. Traditional practices on various islands use bat teeth as a form of currency, primarily for ceremonial events like weddings. This, along with the large bats’ meat, has led to increased hunting which is now threatening the safety of various bat species. The good news is that the demand for bat teeth may also turn out to be a way to help keep these same species alive.

Hunting bats for protein and profit

As their name implies, giant fruit bats eat fruit and are big. The Pacific flying fox (Pteropus tonganus), for example, can have a three-foot wingspan while weighing a under two pounds. That may be smaller than your average chicken, but it’s big enough to make these bats a target for islanders looking for scarce sources of protein. It also means that the bats grow teeth large enough to trade and even drill holes in for use in jewelry. While P. tonganus aren’t technically endangered yet, they’re one of many species of bat that are hunted on the Solomon Islands without much care for population management or conservation.

Dietary needs are of course hard to ignore, but trading in teeth has certainly raised a few eyebrows throughout history. Solomon Islanders have been using teeth as currency for centuries, with the practice temporarily dropping off in the 19th century, around the arrival of Christian missionaries. The teeth haven’t only come from bats either, as dolphins have also been hunted for their teeth and meat in a similar manner to the bats. These practices saw a revival around 1948, and while younger islanders feel like these traditions are once again on the decline, they’re still significant enough to make an impact on local ecology. Since these bats are key seed dispersers for the islands, any shift in their populations can spell trouble for the plants, and other animals, that depend on them.

Using culture to motivate conservation

Conservationists focusing on fruit bats suggest that the continuing use of teeth may actually be an opportunity. The fruit bats need better protections from hunting, but also from indirect threats like habitat loss where their deaths are simply an unfortunate byproduct of other goals. However, if the bats’ teeth retain their cultural value, than the bats’ lives will too. The hope is that educating people about the bats’ vulnerability will inspire people to protect them as part of preserving their people’s traditions. Banning hunting outright might help in the short term, but it probably won’t make people feel invested in the bats’ continued success on the islands either, exposing them to further habitat degradation. Promoting teeth as tender as a way to save bat lives may seem counterintuitive, but it’s not a terribly far-fetched idea. Other animals, from sharks to pigs, may also stand a better chance at survival if humans maintain our reason to kill some (but not all) of them.

Source: How to save giant tropical fruit bats: Work with local hunters who use bat teeth as money

On October 16th, 2017 we learned about

Gravitational waves help scientists spot the collision of two neutron stars

My daughter loves hearing about astronomy, as the movement of the planets, the unfathomable scale of the universe, and unanswerable questions like “is the universe contained in something?” really excite her imagination. So with today’s announcement that astronomers had finally observed the collision of two neutron stars, it seemed like the perfect story to share with her. If only we hadn’t gone out for candy-laden frozen yogurt an hour earlier…

Me: So once up on a time, two stars blew up.

Four-year-old: That’s bad.

Eight-year-old: It happens eventually to all stars, right?

Me: Well… many of them? The point is the stars were the right size to use up all their full, supernova and be left as neutron stars.

Eight-year-old: What’s a neutral star?

Me: “Neutron,” but that’s a good connection to make. A neutron star is the remains of a star that’s basically made of neutrons, which is a neutrally-charged part of an atom, as compared to positive protons and negative electrons. Anyway, the important thing here is that a neutron star is incredibly dense. You remember density?

Eight-year-old: That means it’s… hot?

Me: No, it’s not about how much energy it has, but how tightly packed together all of it’s material is. So in this case, imagine something that if you put it on Earth somehow would weigh more than our Sun, but was small enough to fit in a space between San Francisco and the San Francisco Airport.

Kids together: Whooooaa…

Me: Yeah, it’s so packed together that–

Eight-year-old: But is it hot?

Me: Well, it’s not inert. It has some some energy as we’ll see, but I’m not sure about its temperature. [Post-bedtime fact-check: Neutron stars are hotter than Earth, but cooler than most stars.]

So the mass of a neutron star is so dense that a teaspoon full of neutron star would weigh a billion tons. They’re a ton of stuff in a small amount of space. But all that ‘stuff’ means that they have a lot of gravity, which is imporant when these two stars started circling each other. As they drew closer, they started orbiting each other, but also tearing each other apart.

Kids: Oooo….

Me: As they spun closer and closer, their immense collective mass started emitting gravitational waves. Do you remember the last time we heard about those?

Eight-year-old, now hanging upside-down off the couch: Uh….

Me: We last heard about this when new sensors detected two black holes crashing into each other. The impact send out waves that were basically warping the universe just a tiny bit, and sensors at two seperate buildings were set to notice when lasers were stretched a tiny bit?

Eight-year-old: Oh right!

Me: Well, those two facilities were called LIGO [Laser Interferometer Gravitational-Wave Observatory], and now a third set of sensors has been set up in Italy, called VIRGO, which is doing the same job. To get back to our neutron stars, we know that 130 million years ago, the two stars finally collided, because the waves from their collision arrived at the Earth, and were picked up by these sensors, around two months ago.

Eight-year-old: Two months ago?!

Me: The collision was very far away- around 130 million light-years. The cool thing was that when the gravitational waves were detected, people were notified to jump into action and start looking for the light that they were expecting to follow.

This kind of collision had been predicted, and the size and shape of the gravitational waves looked like what people expected of crashing neutron stars. So they thought that, unlike a black hole, there’d be some light for telescopes to see. Lots of people at observatories around the world started scanning the sky to find traces of the exploding neutron stars, which is called a kilonova.

Four-year-old: What’s an observatory?

Me: A place with a high-powered telescope.

Eight-year-old: Does that mean it was in the sky the before? Did the constellation [Hydra] change?

Me: They did get to see it, but it wasn’t previously visible.

Many, many teams started working together to look for the colliding neutron stars. One guess is that 25 to 30 percent of all astronomers on Earth helped out with this to get as much information from different telescopes as possible. Finally, someone [Charlie Kilpatrick] from UC Santa Cruz, nearby, found a new bright spot near another star. He told everyone to “look over here!” and you could see a blip appear over time. First it was blue, then red, and then dimmed away to nothing.

It was emitting light, but also something called gamma radiation, which is just a form of energy. We can’t see it, and it usually just flys right through us without doing anything. A lot of it was released in the collision, which is what all the telescopes were really looking for.

We had talked about what it meant to be an “author” on a paper the other day, right? Well, one of the papers about this event has about 3,500 authors on it because so many people helped out.

Eight-year-old: You’re like an author, right Daddy?

Me: Well, not like that kind of author.

Eight-year-old: But you write about science stuff.

Me: But I’m not contributing to experiments or anthing. It’s different…anyway…

Eight-year-old mumbling something…

Me: Because there was so much mass and energy between the two stars, when they smashed together they could essentially make a lot of new atoms. Not making them out of nothing, but recombine material to make new atoms that don’t get created all that often. Most new atoms made by stars are light, like hydrogen, but in this case the neutron star was making heavy metals, meaning silver, gold, platinum, and…

Eight-year-old: Gold?! Oh! Money money money money money…

Me: Uh, yeah. They estimate that there was probably so much gold created in this collision you could ball it up into something the 10 times the size of Earth.

Both kids: Whoaaa….

Eight-year-old: You could be soooo rich!

Me: If you could do something with it, yeah. We use gold for lots of stuff, like some of Mommy’s jewelry, or inside electronics like cell phones, and–

Four-year-old: I want to see Mommy’s jewelry!

Eight-year-old, upside-down again: Inside phones?! Money money money money money…

Me: Ugh… right. So to have any of these metals on Earth means that before the Earth was formed, other neutron stars must have collided and released all these metals, some of which got bundled with the other rocks and dust that eventually clumped together to form the planet. We now dig these things out of the ground to use for all sorts of stuff, like earrings or even dipping strawberries

Eight-year-old: People do that? What?!

Me: Yeah, we put use gold for all kinds of things, but my point is that none of it was from Earth originally. It all came from these huge explosions in space!

Eight-year-old: …my friend said she bought gold for two dollars. Is that real?

Me, realizing I’ve totally lost my audience: If it was a small amount. Two-dollars worth of gold.

Eight-year-old: So it’s made up? The price?

Me: Prices are only what we decide… look, people predicted this is where these heavy metals came from, and now for the first time we’ve been able to observe that happening. We’ve never seen neutron stars colliding before! This work also helps us learn about the expansion rate of the universe, because we can now compare the speed of the gravitational waves to the speed of the gamma radiation. It’s also an amazing project to have so many people working as a team across the globe in a way that just wasn’t possible before!

Eight-year-old: …

Me: You know, platinum is worth more than gold per ounce?

Eight-year-old: Money money money money money…

Me: Bed time?

Source: In a First, Gravitational Waves Linked to Neutron Star Crash by Nadia Drake, National Geographic

On October 15th, 2017 we learned about

Chimpanzees’ use of sticks to stab and scoop shows two sides of tool invention and innovation

While humans love our tools so much that we strap them to our faces, we’re certainly not the only animal to use objects to improve our lives. Crows use sticks to access food, monkeys use rocks to open nuts, and dolphins use sea sponges to find hidden prey. In many of these cases, there seems to be a cultural component to the spread of any particular technique— the sponging dolphins, for instance, only pick up those particular foraging behaviors if their mother teaches them. In chimpanzees, the transmission of tool use is less clear, as some stick use seems to be localized, while other studies have found that chimps’ may have some innate ingenuity the is the mother of their inventions.

Shared strategies for sharpened spears

An example of an apparently localized specialization can be seen in the chimpanzees of the Fongoli savanna in Senegal. Many chimps are known to wield sticks for various tasks, like fishing for termites, but this group has invented a tool that’s engineered for use as a probe and a spear. There’s a five-step process making these spears requiring cleaning the shaft of twigs and leaves, plus chewing one end to sharpen it into a point. Once finished, the weapon-wielding chimps would then use them to both find and spear bush babies hiding in trees, going as far as to check the tips of their spears for traces of blood to know if they were on target or not.

Like much tool use, these spears opened up new opportunities for chimps that didn’t or couldn’t participate in the group’s primary hunting activities. Adult male chimps hunt for meat by other means, but the specialized spears allow female and juvenile males to find their own food, a strategy that becomes more important when other food sources are seasonably scarce.

There’s a good chance that the development of these spears and their usage is the result of iteration and cultural transmission of knowledge. More and more examples of animals learning from the examples of their peers and parents are being discovered, even if it’s not strictly tied to tools. Other researchers have been curious about tool use in the other direction- how does it get started? Based on the example above, if a generation of chimps grew up without the tools and techniques invented by their parents, would they be left bewildered when presented with rocks, sticks or other would-be tools?

Scooping with sticks, from scratch

A separate study looked into just that, presenting captive chimpanzees as the Twycross Zoo with some raw materials that are regularly manipulated by some of their wild counterparts. Wild chimps are known to use sticks to collect protein-rich algae from rivers and ponds, basically like crude fondue-forks. Under the assumption that, like spearing bush babies, this method for algae-scooping had been taught by one chimp to the next, researchers gave captive chimps some nondescript sticks and buckets of water with bits of food floating in it. They wanted to see what the chimps would come up with to solve this little challenge on their own.

The captive, naive chimpanzees not only engaged with the task, they started scooping food in a very similar manner to their wild kin. The resemblance to the wild algae scooping was significant, as the captive chimps even adopted the same scooping motion to use their sticks. This all suggests that at least some of the object manipulation that chimpanzees engage in is built into their brains to a certain extent. It’s not necessarily singularly-focused instinct, but a predisposition for exploring what objects can do. Expanding this line of thinking out to other primates like humans, we know that human brains have internal reward loops for learning new things, and so this kind of foundation may be enough to get us to experiment with just about anything we can get our hands on, including sticks.

Source: Chimpanzees Learn to Use Tools On Their Own, No Teaching Required by Leah Froats, D-brief

On October 15th, 2017 we learned about

The plants that deter their demise by becoming more toxic and doubling their DNA

While people often become vegetarians or vegans to avoid causing harm to animals, there’s plenty of evidence that plants aren’t much happier about being eaten than any animal. Sure, fruit can be tasty and enticing so that a plant’s seeds will be distributed, but the leaves and stems themselves are more likely to be bitter or dangerously toxic for interested herbivores. If the plant itself is eaten, it will probably miss its chance to reproduce, a goal so significant that some plants actively respond to threats as they occur. This may mean trying to regrow lost leaves or stems that were chomped off. Or it could mean a plant will warn their kin to increase their production of nasty toxins to scare off incoming insects. Or, in plants known appropriately dubbed “overcompensators,” a single plant will adopt both strategies at once, fighting back the threat of being consumed so vigorously that they end up better off after being bitten than if they lived their whole lives untouched.

The ideal scenario for an overcompensating plant is to be nibbled on enough to trigger its defenses, without causing so much damage the plant can’t carry on. Once a primary stem is bitten or clipped, plants like the mustard Arabidopsis thaliana will increase their growth rate, regrowing the lost stem two to three times faster than it originally grew. To make sure the plant isn’t simply restocking some herbivore’s buffet, the plant will also increase the amount of toxins it produces so that it theoretically won’t get munched on again. This two-pronged strategy not only helps keep the plants alive, it may even give them a boost, as they have been found to enjoy greater reproductive success, spreading more seeds, than plants of the same species that never responded to danger.

Pumping out proteins

As from the energetic cost of tacking both toxins and regrowth at once, the weird part of these abilities is just how the plants make themselves grow faster. Normally growth involves a cell cloning its DNA then dividing into two so that each resulting cell is copy of the first, complete with cells walls, mitochondria, etc. Those cells can then do whatever job the original cell was doing before, like making proteins vital to the plant’s metabolism. These overcompensating plants speed up growth with a process called endoreduplication, which tries to get twice as much out existing cells, rather than having them split themselves in two. A cell’s DNA will be copied, but both copies stay put and go to work. This means that that first cell can kind of multitask, encoding two proteins simultaneously using both strands of DNA, but without the overhead of a second cell’s other organelles. As it happens, the molecular triggers for endoreduplication also help kick off toxin production, making overcompensating a rather elegant package for a plant to adopt.

Researchers are hoping that this package is also transferable to other plants. While 90 percent of herbaceous flowers currently engage in endoreduplication, there could be big benefits if commonly farmed crops used it more often. Responsive toxicity levels could reduce the amount of pesticides needed to protect plants like cotton. Higher growth rates would be appreciated in all kinds of crops, shortening the amount of time necessary to get a full year’s yield. There’s more work do be done, but farms may someday be able to significantly boost their crops’ growth with just a bit of well-intentioned pruning.

Source: Some plants grow bigger – and meaner – when clipped, study finds by Diana Yates, Illinois News Bureau