Wednesday, 30 September 2015

Study Spotlight: The Virtues of Laziness

Special thanks to this week's guest illustrator Tina Do, the world's newest entomological artist!

Generally speaking a good Sketchy Science article is one that requires a lot of research. Each miscoloured word in our article archive represents a resource that took time and effort to track down, read and integrate into the story. Every so often, though, a single resource stands out for its peculiarity and warrants an article all to itself. That is the case this week as we shine the Sketchy Science Study Spotlight on some new research from the University of Arizona that may help you feel a bit better about putting your feet up.
If you know anything about ant colonies, you know that every individual has a job that contributes to the well-being of the entire group
. It is a metaphor that is often used to encourage unemployed teenagers with too much free time to drop off a resume at the local burger joint; but, as it turns out, those lazy teenagers might just be manifestations of a law of complex systems: some individuals just don’t want to work.

Researchers working on the new study discovered that certain ants of the species Temnothorax rugatulus seem to specialize in inactivity. While most members of their colonies busy themselves building things, finding food or tending to the queen, these ants spent their time not doing much of anything. The apparent laziness wasn’t confined to a single colony either, it was seen in all five of the groups the scientists looked at. While this kind of behaviour is grudgingly tolerated in human society, the researchers wondered why the cold, indifferent hand of nature wouldn’t act to sort out the free-loaders. They came up with a couple theories:

Flexibility and Robustness – The first explanation is based on the merit an individual brings to a group simply by existing. As cold and indifferent as nature is, it is also unpredictable. One day might bring a bountiful supply of leaves or whatever, while the next day could bring a flood or an invasion from a neighbouring ant colony. The best way to be prepared for the things you cannot anticipate is to have some spare legwork waiting in reserve. Put simply by one of the researchers, “it’s better to have too many workers during the down times than not enough during the peaks.”

Threshold Response – Another possible explanation for lazy ants is that individuals might naturally vary in the threshold at which they begin working. To draw an example from the human world, if you’ve spent much time in the homes of university students you understand that different people can tolerate living in different degrees of filth. While one person might leap for the laundry detergent at the site of a single sock on the floor, others won’t lift a finger until they have run out of clothes, other still may never in fact learn that the apartment they are renting even has a laundry room. Some ants, the explanation goes, may not have the “pitch in” switch in their brains turn on until the colony is falling apart at the seams.

Colony Size – Finally, the researchers hypothesize that laziness in ants may just be a product of colony size. Ants in small colonies may be called on to do any number of jobs, so they must be prepared to do any of them at a moment’s notice. In larger colonies, work tends to be very specialized and when an ant with a specific purpose finds no work to do that matches it’s particular set of skills, it may just sit and wait until there is work to be done. The same phenomenon can be seen in small and large companies. In this writer’s experience, you are much more likely to find slackers at a massive corporation than at a small non-profit where resources are limited.

So why does any of this matter to use humans? Well, aside from the comfort of knowing that laziness might not be confined to our species, the lessons apply to the complex systems that power our culture. The researchers point out in an interview with Futurity that, “in cloud computing, where you have a network of servers working together to store or analyze data, you end up with some servers that are completely inactive.” It is just a naturally part of the way systems organize.

That is all well and good from a science perspective, but good luck explaining it to your boss next time he catches you playing Candy Crush.

Friday, 25 September 2015

Sketchy Fact #97: Unfortunate Frogs

Until the 1960’s, the most reliable pregnancy test available was to inject a woman’s urine into an African clawed frog. If the woman was pregnant, the frog would ovulate.

Tuesday, 22 September 2015

Weird and Distant: What's the deal with Pluto?

For such a cold place, Pluto is a pretty hot topic among those who get excited about space. Especially over the past few months, with the data collected by NASA’s New Horizons spacecraft, Pluto has found it’s way into news headlines and even managed to surpass Micky Mouse’s dog for the top ranking image when you search its name. Not since 2006, when Pluto was stripped of its status has a planet has the world been so fascinated with this mysterious, distant snowball.

But what happened back in 2006 anyway? Why after more than three quarters of a century did scientists suddenly decide that Pluto should be kicked out of the club? It’s an interesting story that has as much to do with Pluto itself as it does with our understanding of what words mean and what cool stuff is floating around in our solar system. In the end, the more we learn, the harder it is to sort out all the information.

Pluto was discovered by American astronomer Clyde W. Tombaugh on Feb 18, 1930 and it was immediately evident that something weird was going on. For a long time astronomers has been searching the sky for an elusive ninth planet, but Pluto wasn’t at all what they were expecting. The thing about the solar system is, before 1930, it kind of made sense. At the heart of the show was the sun: the massive fiery ball of gas that we all know and love. Moving outwards from the centre we had a quartet of small, rocky planets (Mercury, Venus, Earth, and Mars); followed by a rocky interlude known as the asteroid belt; then four ginormous planets made mostly of gas (Jupiter, Saturn, Uranus, and Neptune). There was a nice symmetry to things and scientists were fairly confident that any other planets they found in the outer reaches of the solar system would also be ginormous and gasy.

Pluto is neither of those things. First, it is small. So small that even spotting it was kind of a miracle. Pluto is 2,370 km (1,473 miles) in diameter, making it about two thirds the size of the moon (3,476 km) and less than half the size of the next smallest planet, Mercury (4,878 km). Second, Pluto is not gaseous. It is made of rock, ice and snow. On top of that though, there is lots of other weird things about Pluto. While the rest of the planets orbit the sun on a relatively flat plane, Pluto’s orbit is rakishly tilted 17-degrees, like a 20's-era mobster’s hat. Its orbit also crosses Neptune’s. Fortunately, due to the effects of their gravity on one another, they will never collide.

As small and weird as it may be, Pluto was happily admitted as the solar systems ninth planet. And so it remained until we had some things to compare it to. Actually, that isn’t entirely true. We have long known about another object in the solar system that poses problems for Pluto’s planet status. The object is Ceres, and though it doesn’t show up on any classroom diagrams, it sits in between Mars and Jupiter, happily going about its business. But Ceres is only 950 km (590 miles) in diameter, so even after discovering Pluto we were happy to label it as just the largest asteroid in the belt.

Pluto’s problems really began on January 5, 2005. Leading up to that date astronomers had been discovering objects that were similar to but smaller than Pluto out in the far reaches of the solar system. But is wasn’t until one astronomer named Mike Brown, author of the surprisingly thrilling and wonderfully titled How I Killed Pluto and Why It Had It Coming, discovered an object called Eris that the world had to stop and ask “Okay, so what they hell is Pluto?”

The problem with Eris is that it appeared to be bigger than Pluto. We now know that Eris is a hair smaller at 2,340 km (1,454) across, but it is still basically Pluto’s twin. It orbits outside of Pluto, at a rakish angle to the rest of the solar system and generally infringes on everything that once made Pluto special. The trouble was, if we called them both planets, there would be very little stopping us from having to include the hundreds or thousands of other objects in the outer solar system (the Kuiper Belt) as planets.

That simply isn’t practical, so astronomers sat down and finally defined what the word “planet” meant. Here’s what they came up with:

“A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood [sic] around its orbit.”

The upshot is that since both Pluto and Ceres cross the orbits of other objects, they can’t be called planets. Instead they are “Dwarf Planets”:

“A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood [sic] around its orbit, and (d) is not a satellite.”

There are five officially recognized dwarf planets in the solar system: Pluto, Eris, Ceres (upgraded from ‘asteroid’), Haumea, and Makemake. So although not being able to call Pluto a planet anymore seems to make the solar system a slightly lonelier place, in reality, we’ve gained a lot more company.

Friday, 18 September 2015

Sketchy Fact #96: The World's Biggest Invisible Animal

Polar bears are nearly invisible to infrared cameras because their fur is transparent. That makes it very hard for scientists to count them since infrared cameras are one of the most useful tools we have for finding animals in the wild.

Wednesday, 16 September 2015

Whale Fall – More than just a hilarious existential crisis

Whale fall. It may sound like the rejected title of a James Bond movie or a Douglas Adams reference, but it is actually a surprisingly important and relatively little known concept in the study of the world’s oceans. It all begins with one of the saddest moments in the story of any whale family. Grandpa whale, let’s call him Moby, after a long a fulfilling life of eating ship captains’ legs, dies. 

As sad as this is for the rest of the whale family, odds are that if Old Moby died from natural causes he lived a pretty long life. Research beginning in the 1990’s revealed that a significant portion of the population of many whale species is over 100 years old. Questions started being asked when whale carcasses were pulled from the ocean containing stone harpoon heads, which fell out of fashion around 1860. Tissue samples from a group of Bowhead whales subsequently revealed that several were in their mid-100’s and one male was pushing 200. The point is whales can live a long time.

When a whale dies without human intervention its body either washes up on shore, occasionally with hilarious consequences, or it sinks to the bottom of the ocean. The latter is much more common and the result is something pretty remarkable.

When a whale fall, as these things are known, touches down the animals that live on the sea floor throw a party. The deep ocean is a surprisingly poor environment in terms of available food and energy with animals living mostly on small particles of so-called “marine snow” that drift down from above or by eating each other. A whale carcass, as you can imagine, is a welcome break from this kind of life.

The first phase of a whale fall food chain involves getting all that delicious, rancid flesh off the bones. That job is taken care of by animals like ratfish, sharks, crabs, and hagfish. The work goes surprisingly quickly. These scavengers can liberate up to 60 kg (132 lbs) of meat in a day. After a few short months (whales are big animals) only a skeleton remains. At first glance it would seem like the show is over, but in reality things are just heating up.

As the crabs and sharks pack up and move on to greener pastures, worms move in. Lots of worms. Polychaete worms, to be precise. Up to 45,000 worms per square meter blanket the sea floor about one year after the whale buffet opens its doors. They, along with a few other species of invertebrates, feast on the organic material in the whale bones. Although this stage of whale decay brings huge numbers of animals, they represent only a few species. The real fun begins when the microbes arrive on the scene.

Somewhere between one and two years into the show, most of the low hanging fruit (to use a more pleasant sounding metaphor) has been harvested. At this point sulphur-reducing bacteria arrive to feed on the fats and oils left in the skeleton. As they do this they release sulphur into the surrounding water, which attracts sulphophilic (sulphur-loving) bacteria. These bacteria, remarkable, form the basis for a very unique food web.

Most food webs on Earth begin with photosynthesis as plants turn sunlight into food. The web around this stage of a whale fall by comparison is chemosynthetic, meaning that it’s basis is chemical reactions by bacteria. Larger and larger animals feed on the bacteria and on the creatures that feed on the bacteria until eventually you have a booming community that includes up to 190 different species of visible animals. The only other place where this type of system exists is around deep sea vents where the energy comes from within the Earth itself.

These Stage Three whale fall communities can last a surprisingly long time. We're talking decades. Research has shown that some whale falls can sustain an ecosystem for over 50 years! And these are not rare systems. Given the number of whales alive today and the length of time that these communities last, scientists estimate that there may be a whale fall every 5 to 16 km (3 to 10 miles) along the sea floor, meaning that when the nutrients finally do run dry, the creatures that depended on them don’t have far to travel until they find their next home.

Whale falls are islands of biodiversity in one of Earth’s least bountiful places. Yet another reason why humans should do our part not only to protect whales, but to protect the fish and oceans that they depend on.