Sketchy Fact #82: Foot for thought

Butterflies experience taste through their feet. They are like tiny flying Andelites, complete with morphing capabilities.

Metamorphosis: Ch-ch-ch-ch-ch-changes

Elementary school science classes do a great job of engaging young people with the amazing way that things in nature work. They spark enthusiasm for learning and create a passion for science in some kids that eventually leads them to careers of great discovery. The thing about introductory science, however, is that it needs to cover a lot of material in a very short amount of time. The result is that some of the most fascinating topics tend to get glossed over and kids miss out on appreciating how weird and amazing certain things are. This is especially true for the subject of metamorphosis.

 Even the high-level, detail-free version of metamorphosis we get taught in grade school is pretty amazing. An animal begins its life as one thing (the usual example is a caterpillar), enters a period of pseudo-hibernation and emerges as something totally different. As incredible as this seems, you may not have ever stopped and put together the fact that the majority of animals follow this sort of life plan. Nearly all insects look very different at the beginning of their lives than they do at the end, and since insects make up the vast majority of animal species, metamorphosis is more the rule than the exception. Generally speaking, it is weird that you didn’t spend your teenage years in a chrysalis.

The reason that evolution has selected this approach to life for so many animals is amazingly straightforward. If the adult version of an animal inhabits a completely different ecological niche than its offspring, the mature and immature versions of that animal are not competing against each other for food. Caterpillars spend their days munching leaves whereas most butterflies get all their meals through their straw-like proboscis. In the case of the Atlas Moth, the adult version doesn’t even have a mouth. It relies only on fat storage to survive its adult life. It is hard to complete with your children for food when you don’t even eat.

So metamorphosis is a cool, albeit common approach to life on earth, but how does it happen? Most of us are under the impression that after it has munched its last leaf, a caterpillar finds a safe spot and encases itself in a hard shell, inside which it grows wings, antennae, and the other anatomical necessities of adulthood. In fact, what happens it far weirder. The freshly fattened up caterpillar will either attach itself to the underside of a stick, or use silk to create a hammock of sorts to suspend itself. From there, the caterpillar sheds its skin to reveal the chrysalis, which eventually hardens into a shell.

What happens inside that shell is decidedly stranger than you probably think. Rather than simply adding wings onto its usual body plan and calling it a day, the caterpillar effectively digests its own body. Most of the structures get broken down to their constituent proteins and put back together in a totally new form. It is a bit like taking apart your Lego skyscraper to build a car, only the Legos are alive and a lot more gooey. If you cut open a chrysalis, you would basically just find a soup of animal fluids that don’t at all resemble a caterpillar.

Interestingly, at least some of the memories that caterpillars form survive the metamorphosis process. Research at Georgetown University has shown that if you train caterpillars to avoid certain smells, the butterflies they become show the same behaviour. This is because not all the parts of a caterpillar’s body get broken down. The guts and breathing tubes (in addition to the brain, presumably) remain intact and undergo only slight changes.

In the end, whether it is a caterpillar turning into a butterfly or a maggot turning into a fly, metamorphosis is worthy of the label “craze-mazing.” You could almost be jealous if the life expectancy of the average butterfly weren’t less than a year.

Sketchy Fact #81: Gecko Problems

Geckos can't blink because they don't have eyelids. They have to lick their own eyeballs to remove dirt and other miscellaneous gunk.

Our Bi-Polar Planet – Magnetic Reversals and Death from Above

Special thanks to reader Mark L. for this week's polarizing topic.

If you’ve ever spent time navigating in the outdoors or sitting in an elementary school science class, you understand that the Earth is a gigantic magnet. If you’re the curious type who digs into these things a little deeper, you probably know that that is a wonderful thing. Besides being able to find your way home with a compass if you ever get lost, the magnetism of the Earth creates a protective bubble that blocks harsh solar particles from reaching the Earth and bathing us in radiation.

As agreeable as this state of affairs is, there is something you should know about the planet you are in a long-term relationship with… It’s unstable. Avid outdoorspeople are all aware of something called magnetic declination: the difference between true north and magnetic north. As it happens, your compass points to the Earth’s magnetic north pole and your map is oriented towards “true north” – the point around which the planet spins – and those are not the same thing. In fact, the magnetic pole tends to wander. On average, it moves in loops of around 80 kilometers (50 miles) per day and the annual average of those daily points moves around 41 kilometers (25 miles) per year.

That might pose a slight inconvenience for hikers and sailors who have to keep up with revised estimates of what exactly they are walking or drifting towards, but it is generally something we can deal with. The real problems happen when our planet moves from mildly unpredictable shifts to outright mood swings. When those happen, the north pole and south pole can actually switch places.

The Earth’s magnetism is caused by the movement of molten iron in the planet’s core. Way down beneath you, wherever you are reading this, is a solid iron ball at the centre of the globe. Around that is another, larger ball of liquid iron. The inner part of that outer core is hotter than the outer part and the difference in temperature causes iron to drift up and down and create currents (hot iron rises, cold iron falls). When those currents speed up, the magnetic field around the Earth gets stronger. When they slow down, the field gets weaker.

When the field gets too weak the north and south pole flip back and forth until things stabilize. In the distant past, this was a pretty rare event… but still probably more frequent than you would guess. Between 1.5 and 2.9 billion years ago a flip happened once every 5 million years or so. Since then, the outer core has cooled and the inner core has grown. The result is less stability and now the poles flip, on average, once every 200,000 years. The last switch was 780,000 ago however, so we are very much due.

So will the poles switch in our lifetime? Surprisingly, the answer is “Yeah, maybe.” These things are hard to predict with any degree of certainty but over the past 150 years the strength of the magnetic field has been weakening by about 5 per cent per decade whereas before that it weakened by about 5 per cent per century. That could mean that one day in the not too distance future, your compass will be useless.

What does that mean for life on Earth? Overall, probably not much. As I mentioned, the poles have flipped and flopped literally thousands of times in Earth’s history. We know this because the magnetic elements in very old rocks show patterns of alignment that only make sense if the poles were in different places. No big animal or plant die offs correspond with these changes, so we will probably be okay. The major risks are increased solar radiation, raising your risk of skin cancer (sunscreen up!) and communications being wiped out or messed up. It turns out our cell phones and the internet depend on the protection the Earth's magnet field provides.

The irony of the whole situation is if our communications collapse and society crumbles (rather than just reverting back to 1800’s levels), we won’t be able to use compasses to guide our wandering nomadic tribes… I guess it’s time we all buy a star atlas and start studying. See you on The Road, everybody!

Sketchy Fact #80: Electro-Ladder

The San Francisco fire department is one of the last in North America to use wooden ladders because wood does not get electrified when it touches streetcar cables above the road... As a bonus, the ladders last longer because wood doesn't get weaker if you stress it over and over like aluminum does (think of a crinkled pop can).

Human Echolocation: You’re only as blind as you want to be

This article goes out to the amazing Amy Kux on her birthday. Happy birthday Amy!

If you take a stroll around the animal kingdom and look at all the amazing abilities that different creatures possess, it is easy to become jealous. Sure, us humans are the brainiest of the bunch and we have used our smarts to make up for some of the physical deficits nature has left us with, but riding in a car going 70 miles (112 km) per hour just doesn’t have the same coolness factor as being able to reach that speed on foot, like a cheetah can. Even the best human sprinters would be hard pressed to catch a squirrel. We can’t fly like birds or swim like dolphins. We aren’t as strong as gorillas and we can’t track criminals with our noses like a bloodhound. However, there is one superhuman ability that science is beginning to realize that some of us have an unexpected knack for...

Most people are familiar with the concept of echolocation. It is the ability of some animals (ex. bats, some birds, whales, and dolphins) to detect objects in their environment by emitting high frequency sounds and listening to how they bounce of different surfaces to create a sort of mental image of the world. Typically these sounds are too high pitched for human ears to pick up, further adding to the mystique of this impressive skill. The thing is, it might not be so beyond our ability to grasp.

We don’t spend a lot of time thinking about how we perceive sounds, so it is easy to think that we aren’t very good at it. Humans have evolved to rely on our eyes to a ridiculous extent. The idea of losing our vision is terrifying to some people, but that is likely because most of us have never tested our ability to navigate using other senses. Rest assured, you are more skillful than you think. If you don’t believe me, try to think back to the last time you were in a really big space like a church or an airport terminal. Think about the things you heard and how they were different from the sounds that reach your ears while sitting on a soft couch in a carpeted room. Odds are if I blindfolded you, put you in one of those places and asked you which it was you wouldn’t have much trouble telling me.

Beyond the ability to distinguish between when we are at home watching Netflix and when we are about to board a plane to Prague, our ears are also good at determining the direction that sounds are coming from. You probably don’t realize it, but when you hear a bird chirp or a car backfire your two ears receive the sound at slightly different times. Your brain is able to use this difference to determine where in space the noise came from and we can turn our heads toward it without even thinking. Just like how your two eyes let you see in three dimensions, your ears let you hear in three dimensions.

A few of us, it turns out, can take what our ears can do to a level that is beyond belief. Some people who have been blind for a long time can click their tongues and detect the way the sound waves bounce off objects around them, very similar to how bats and whales do it. Apparently this is actually something that most people can learn to do. One study found that, over time, blindfolded participants could learn to tell the difference between large and small objects placed in front of them using only tongue clicks. With more practice, research has shown that people can learn to walk down hallways while blindfolded without touching the walls simply by listening to how sounds are echoing around them.

Human echolocation is something that people like Daniel Kish, founder of World Access for the Blind, have known about for a long time. Kish, who lost his eyes to cancer as a toddler, taught himself to echolocate as a child so he could know how high up he was in the trees he was climbing. As an adult he is often annoyed at the surprise people express when he rides by them on his bicycle, clicking all the way. Experts like Kish, research has shown, can use clicks and head movements to determine the distance, size, density, movement and even the contours of objects.

Kish’s message to other blind people is not to believe the world when it tells you that you can’t do something. You are as capable as you believe you are. That’s something we should all try to remember, especially as we navigate a world full of animals that appear to have us outmatched.

Sketchy Fact #79: Metatarsal Moisture

Your feet alone sweat half a pint of liquid every day. Socks have basically the worst job of any article of clothing. 

Concussions: Brain Damage for the Every-Man

Disclaimer: Our guiding principle here at Sketchy Science is the belief that science is fun and that understanding the way things work can give you a deeper appreciation for the world you live in. With that in mind, we try to have fun and make jokes. We plan to continue that today, but keep in mind that this topic is a serious one. We hope this information can promote some good judgment among our readers.

Have you ever hit your head really, really hard? Most people have done it at least once and it is a pretty unique experience when it happens. Your vision blurs to a total white out, you stagger on your feet, you can’t think or speak for a few minutes, you might even lose consciousness. Few things cause a person to panic as quickly as losing control of their own brain, but that is exactly what a concussion is.

One of the coolest things about neuroscience is the ridiculous relationship between cause and effect. If I put an electrode in your brain in just the right spot and switched it on, I could make you pick your nose or slap your face or yell out your deepest darkest secrets in a crowded operating room. Your brain is an incredible network of cells that uses electrical impulses to control every part of you. In a very real sense, those electrical impulses are you. That’s why a blow to the head messes you up so badly, so quickly.

Basically, a concussion is what happens when your brain and your skull disagree about where they are moving to. Your brain is in motion, and as all things in motion do, it wants to stay in motion. But sometimes something blocks your way and brings your skull to a crashing halt. Examples may include a wall, the sidewalk, or a 350 pound linebacker. When this happens, your brain slams into your skull and as you might expect, bad things happen.

Blood vessels can tear, swelling and bruising can set in. Your brain may be the most complex organ in your body, but when you smush it a little it reacts the same way all your other organs do. The downside is that swelling and tearing in your brain prevents your body from functioning properly.

The obvious symptoms (headache, blurred vision, unresponsive pupils) can last anywhere from a couple days to a couple months. However, just because you stop noticing the effects doesn’t mean you are back to 100%. Research has shown that abnormal brain function can continue for years following a concussion.

That may sound really bad, and in a sense it is, but the good news is that if you rest and avoid blunt force trauma to the head following a concussion your brain can heal itself and eventually get back to normal. Hits to the head happen. I would even go as far as to say that if you never get a concussion, you’re not being adventurous enough. But, that being said, there are real and serious consequences to getting multiple concussions in quick succession.

In the short-term the biggest threat from a bonk on an already concussed noggin is Secondary Impact Syndrome. What happens with SIS that that your already damaged blood vessels get pushed too far. Your brain hemorrhages, swelling suffocates blood flow throughout your brain, and you either go into a coma or you die. Not fun stuff.

Fortunately SIS isn’t very common. Unfortunately, multiple blows to the head (even small ones) can also cause your brain to scar and degenerate. This condition is called Chronic Traumatic Encephalopathy and it is increasingly being observed in the brains of retired football and hockey players. People with CTE in their 20’s and 30’s have the brains of 80 year old Alzheimer’s patients. CTE can lead to memory loss, depression, loss of motor control, and early death.

Clearly concussions are serious stuff and your brain is something you should probably look into taking good care of. Wear a helmet if you’re playing contact sports and if you even think you have a concussion, take the day off. Get some sleep (the old advice about trying to stay awake is pure myth) and wait out the headaches. It’s a dangerous world out there, so use your head… just not as a battering ram.