Friday, 31 October 2014

Sketchy Fact #65: Super Sleepers

Koalas are nature's sleeping champions. They sleep 22 hours a day, 2 more than sloths, and 4 more than comic illustrators.

Wednesday, 29 October 2014

The Worst Inventor in the World: The Story of the Ozone Hole

Saving the world is a lot trickier than Bruce Willis makes it seem. The more we learn about humanity’s influence on the processes of nature, the more we understand that the earth is a very complex thing, full of dynamic and constantly changing systems. For that reason, people often end up confused and frustrated when we try to undo some of the harm we have caused. Climate change in particular is enough to make people switch off their brains and wait for a new topic. It is a big unruly problem and it often seems like no matter what we do, we can’t fix it. However, recent evidence from Antarctica is beginning to show that the changes we make can have a positive impact on environmental problems

It all began back in the 1930’s with a man named Thomas Midgley, an inventor who was riding high after his creation of a new form of gasoline that solved a problem called engine knocking. His handy solution was to put lead in the gas. Little did he and everyone else on the planet know, but eventually his invention would expand the amount of lead in the atmosphere (and consequently in the bodies of every man, woman, and child alive) so much that it would eventually be outlawed.

But back in 1930 everything was going well for old Thomas. Following his success with tetraethyl lead Midgley took a job with General Motors, a company that hoped he could come up with a chemical for them to use in refrigerators. Back in the early 20th century your fridge was a pretty dangerous thing. The chemicals used to cool it were so poisonous that a small leak could result in your whole family suffocating in their sleep. GM had high hopes that Midgley could fix the problem.

As it turned out, their confidence was well placed and in no time at all Thomas Midgley had his name attached to another invention: chlorofluorocarbons (CFCs). CFCs were harmless to humans and nowhere near as flammable as the old refrigeration chemicals so they quickly became the molecules of choice for keeping your leftovers cool and delicious.

However, along with leaded gasoline, CFCs would eventually become the scourge of the Earth. As it happens, when CFCs get into the atmosphere they destroy a chemical called ozone. Ozone itself is a bit of a handful. It is just three oxygen molecules stuck together, instead of the usual two. At ground level, ozone is not your friend. Your body confuses it with pure oxygen gas and binds it to you red blood cells where it very swiftly kills you. Up in the atmosphere however, where it makes up a 3 millimeter thick layer all around the earth (about the thickness of 2 pennies stacked on top of each other), ozone is great. It blocks harmful UV rays from reaching the surface where they cause skin cancer and sunburns.

As developed nations cranked out CFCs at every increasing rates through the 50’s and 60’s the chemicals found their way into the atmosphere in ever increasing quantities. Eventually they destroyed enough ozone to create a massive hole in the ozone layer that forms over Antarctica between September and December of each year. The hole is isolated to the bottom of the planet because wind currents create the vortex of super-cold air over the South Pole and cold air multiplies the effect of CFCs on breaking down ozone.

Clearly something needed to be done before the entire atmosphere was depleted of ozone and we were all dying from cancer. In 1987 leaders from nations all over the world came together and drafted the Montreal Protocol, a document that would phase out the use of CFCs across the world. The agreement was reinforced in 1997 with the Kyoto protocol. The people of the world crossed their fingers and hoped for the best.

So what was the result? Well, in 2012 measurements of the ozone hole revealed that it was the smallest it had been in over a decade. The ban on CFCs is actually working in ways we can see on time scales we can comprehend. In the world of environmental science, that is a slam dunk. Scientists estimate that by the middle of this century ozone levels will rebound to where they were in the 1960’s and the ozone hole should be completely gone sometime in the next 20 years.

To put a slight downer on an otherwise happy ending, it is possible that the shrinking of the hole we are observing is due to warmer air temperatures caused by climate change mitigating the ability of CFCs to break down ozone, but the effect is larger than you would expect from that alone. The news is still good.

The lesson to take away from the patching of the ozone hole (aside from not hiring Thomas Midgley to do anything ever again) is that we can make a difference. When humanity puts its mind to something, we are able to get it done. We should all go out for a beer to celebrate and then get to work eliminating fossil fuels.

Friday, 24 October 2014

Sketchy Fact #64: The Clap

Gonorrhea bacteria can pull 100,000 times their own weight, making them the strongest creatures on Earth relative to body size.

Wednesday, 22 October 2014

Epidemiology: How to know when things are safe and when they R-naught

As the ebola epidemic continues to rage in west Africa and new cases start to pop up in countries like Germany and the US, people are beginning to pay attention to the study of how diseases spread through groups.  Movies like Contagion  and Outbreak give some idea of the work that gets done when a disease begins to pose a threat, but not many of us really understand the nuts and bolts of the science known as epidemiology. Where do diseases come from? How are they spread? Why has the current ebola epidemic proven to be so difficult to contain if, as we learned a few articles ago, the disease isn’t actually all that easy to catch? It turns out the answers are as interesting as the questions.

Where do diseases come from?

How can a disease like ebola suddenly burst onto the world’s stage? When you stop and think about it, it doesn’t make a lot of sense. If ebola is so deadly and is able to spread from person to person the way it has been for the past 10 months, why isn’t it something that is always going on? Well, in the case of ebola and many other diseases that harm people, the reason is that diseases have reservoirs where they hide out between epidemics.

When I say "reservoir" I don’t mean that there is a dam somewhere and behind it is a churning green soup of ebolavirus. Disease reservoirs are animals that viruses can live within without causing any ill effects. In the case of ebola, the reservoir is thought to be fruit bats. The reservoir for influenza is sea birds. The reservoir for plague is fleas. Every animal out there is a potential host for the next horrifying pandemic. Every so often humans come into contact with these animals in a way that allows diseases to jump into our bodies, this is called a spillover. For more on that, check out this great book published last year by David Quammen. Diseases that spread this way, from animals to people are called zoonoses (plural of zoonosis) and they make up most diseases you can name.

How do diseases spread?

The spread of a disease through a group of people depends on a number of things. Epidemiologists bring a few different factors together to present that information in a neat and tidy number they call R­­0 (pronounced “R-naught” because being British is fun). In its simplest terms R0 is the average number of healthy people that a sick person will infect while they have the disease. Ebola has the same R0 as hepatitis C: 2. That means that if I had ebola I could expect to infect 2 new people before I either died or was cured, maybe my wife and my doctor, or a doctor and a nurse. Either way, a couple of you suckers are going down with me. R0’s of other notable viruses include 4 for HIV and SARS, 10 for mumps, and a whopping 18 for measles.

R0 ­ depends on a few different things: the probability of infection after being exposed to an infected person, the average rate of contact between infected and susceptible people (some people will be naturally immune), and how long the disease is contagious for. What is working against ebola’s R0 ­are the facts that the rate of transmissible contact between people is low (you need to be in physical contact with a person’s bodily fluids to catch it), and the fact that the disease is only contagious when a person starts to show symptoms (which usually isn’t very long… because ebola kills too quickly). Diseases with higher R0 ­are able to spread through the air or survive in water.

Why haven't we been able to stop ebola yet?

Aside from the actual treating of sick people and coordinating quarantines and such, epidemiologists are also disease detectives. It is their job to determine who the first person to catch the disease was in an outbreak (the infamous "patient zero") and by what means it was able to spread. The full story of the current ebola outbreak can be found in Jeffery E. Stern’s article Hell in the Hot Zone, published earlier this month by Vanity Fair – it is definitely worth reading.

The Cliff Notes version is that cutting down the rainforest in West Africa brought people into closer contact with bats, leading to the spillover. After that, the international response was swift and well-coordinated, but it was not communicated well enough. The problem seems to have been that the teams of doctors and scientists in hazmat suits that rolled into the afflicted villages did not tell the friends and family of patients what was going on in a way that they could understand and trust. All those people saw was their loved ones being carried into tents by people in space suits and disappearing forever. After that people got understandably scared of western doctors. They didn’t report infections and the disease was able to spread at the same time that health care workers thought the epidemic was slowing down due to the empty hospital beds all around them. When the disease finally got to the point where it was impossible to hide and people started seeking out treatment, it was too late.

Epidemiology is a very cool field of science that often goes unappreciated. There are currently thousands of hard working people putting themselves at risk to contain the situation in Africa, but they need more help. If intervention isn’t stepped up soon, the rate of new cases of ebola is expected to rise to 10,000 per week, because even with an R0 of 2 the spread is still exponential.  If you are able, please donate to Doctors Without Borders, who are leading the fight against the spread of the disease. Your money won’t only go towards treating the sick, it will buy gloves and masks and proper equipment to help keep those doctors as safe as possible.

Friday, 17 October 2014

Sketchy Fact #63: We don't need roads.

If you could drive your car straight into the air at full speed, you would make it to outer space in a little over an hour.

Wednesday, 15 October 2014

5 Organs You Don’t Need

The human body is a pretty amazing thing. Unless you’re a surgeon or a serial killer you will probably never fully appreciate all the crazy organs that people have and the myriad tasks they accomplish every minute of every day. But as well-evolved as our bodies are, there are a few bits and pieces we could do without. With that in mind, we thought we would take a trip around the body this week to talk about some of its most useless organs.

1.   Male Nipples

Let’s deal with male nipples right off the bat. The only reason they exist is because even the manliest man you will ever meet began life in his mother’s womb as a female. When the developmental process gets started all babies, boy or girl, follow the same plan. It is only later that male genes on the Y chromosome kick in and plant the seeds of beards and all the rest of what makes a man a man. The result is that men end up with a pair of purely decorative chest ornaments that serve only as a target for adolescent pain-inducement before the brain is fully developed.

 2.   Coccyx

You may not know it, but you have a tail. It is a remnant from when our ancestors used to run along branches and swing through trees. Back then it aided in balance and since then it has become essentially a 5th limb for some species of new-world monkeys, allowing them to grip branches and hang hands-free. That is great for the monkeys, bu all it is for most people is a lump of fused vertebrae tucked inside the skin at the base of our spines. For an unlucky few it sticks out and makes them self-conscious. It’s only real function these days is as a dominant scrabble word.

3.  Wisdom Teeth

In the land of long-ago your forebears lived harsh lives. They had to chew tough meat right off the bone whenever they could get it. They also had to catch that meat and risk getting a few teeth knocked out in the process. For that reason humans evolved an extra couple pairs of molars to come in later in life to fill in the gaps. However, now that we have toothbrushes and the like wisdom teeth generally do more harm than good.  The most joy they ever bring these days is to the friends of people who just had them removed.

4.  Erector Pili

Aside from eliciting the occasional chuckle from less mature readers of science blogs, the erector pili are another part of the body that serves no useful function. These are the organs that cause your skin to get all bumpy when you’re cold or afraid. Back when we were covered in body hair, they made that hair stand up to help us hold in extra warmth or to look big and mean. You may have seen an angry dog using its erector pili to raise the hair on the back of its neck during a barking fit. Since humans aren't typically fur-covered anymore, the effect is a little less dramatic.

5.  Plica Semilunaris

Our last useless organ is so obscure that Microsoft Word thinks it’s a spelling mistake. It is the plica semilunaris, more common called your third eyelid. It sits in the inside corner of your eye near the tear duct and you can only really see it if you pull your eye wide open. It used to protect our eyes while letting us still see the world when our ancestors lived underwater. Watch a video of a crocodile about to submerge itself and you will see these transparent eye-covers in action. Unfortunately, in humans they have withered to the point of uselessness, although it would be really cool if they still worked. Built-in ski goggles anyone?
Honourable Mention: The Appendix

One organ you may have expected to find on this list is the appendix; that small dangling protuberance at the point where your small and large intestines meet. Granted they do have a tendency to become infected and 1 in 20 people get them removed with no apparent problems, but your appendix isn’t useless. Recent research has shown that the appendix is a storehouse  for some of the beneficial bacteria we learned about in a previous article. The bacteria lie in wait until things go haywire in your large intestine before riding to the rescue. If the appendix were as useless as everyone used to think, it wouldn’t have hung around the evolutionary toolshed for 80 million years and involved in countless other species of animals. So give your appendix the credit it deserves… Unless it gets infected. Then cut it out like a bad habit.


Friday, 10 October 2014

Sketchy Fact #62: PB&G

In a 1999 book, 250 of the world's greatest minds agreed that peanut butter has no effect on the rotation of the Earth.

Wednesday, 8 October 2014

The Trouble with Tardigrades: The Trials and Tribulations of Nature’s Toughest Animal

Imagine for a moment that you are a hitman for mother nature. It is your job to find and kill any animal she requests. Obviously some contracts are going to be easier than others. Taking the life of a grizzly bear or a great white is going to be a bit more challenging than ending a lamb or grasshopper. However, even sharks and grizzly bears are easy targets compared to nature’s toughest creature. Freeze a shark solid in a block of ice and boil a grizzly bear and your job is pretty well taken care of, but do the same to a tradigrade and you’re in for a long and frustrating wait.

You may not have ever heard of tardigrades, but they are everywhere you have ever been. There are billions and billions of them in every environment on earth. In fact there is a stout branch on the tree of life that contains nothing but the 1000+ species of these little guys. A tardigrade isn’t a bacteria or any other kind of those not-quite animals you hear about being everywhere either, they are honest to goodness animals that you can see with the naked eye… in the right light.

Tardigrades, also known as water bears for their resemblance to very tiny pandas, are on average about 1 millimeter long. That is about the size of the period at the end of this sentence. They are mostly transparent and have eight stubby legs, each ending in an alien/bear/eagle like claw. They spend their days sucking water off of moss and feasting on algae with their spear-like mouths. However, unlike most animals that live in the land of the very small, tardigrades are actually kind of cute in a monstrous sort of way.

They get their name from the Italian word tardigrada meaning “slow walker” because unlike most tiny animals that dart around like Carrot Top on PCP, tardigrades lumber around slowly and pretty clumsily, doing their tardigrade thing. Tardigrades are a scientists best friend because they are small and breed quickly. An individual contains about 1000 cells and has a lifespan of around one year… Unless of course you subject them to the cruelest kinds of punishment imaginable, then they will live WAY longer.

Indeed, a tarigrade is a very peculiar thing. Leave it alone and it will lead a pretty uninteresting life, but if you freeze them, dry them out, cook them, or expose them to radiation you had better be prepared to have your mind blown. Tardigrades can withstand temperatures from 1 Kelvin (-458 F/-272 C) to 148 C (300 F). They can survive pressures 6 times greater than the deepest point of the ocean and brush off a dose of radiation 1000 times greater than what would kill an elephant.

When a tardigrade is thrown into one of these woefully undesireable situations it pulls off an amazing trick. It can dehydrate it’s body by 97%, converting water into a sugar called trehalose which prevents cells from rupturing when they freeze or heat up. When they do this, tardigrades go into a sort of hibernation, almost entirely shutting down their metabolisms. When conditions improve, they simply rehydrate and go back to the business of moss sucking. A tardigrade can survive in its hibernating state for at least ten years but possibly for more than a century.

As if all of this wasn’t enough to bestow them with the honour of nature’s most indestructible creature, tardigrades are the only animals we know of that have survived the vacuum of space. In 2007 NASA sent a team of tardigrades along with a few astronauts up into orbit. They opened the airlock and set the tardigrades floating in space for ten days where they were exposed to extreme cold, extreme heat, and intense radiation. Apparently the tardigrades just treated this as a vacation because when they were brought back to earth they woke themselves up from an extended nap and just went on living. A few even reproduced.

This is all pretty amazing but why does it matter? We can get jealous of tardigrades until the cows come home but it doesn’t help us much, does it? Actually, tardigrades provide good evidence for a long held idea in science called panspermia which is meant to explain where life on earth came from. It is thought that life may have started elsewhere in the universe and been spread by collisions with meteors. When a meteor hits a planet it sends pieces of that planet rocketing into space and drifting through the void. If creatures like tardigrades are tough enough to survive such a trip and land on another planet, life might be a pretty common feature of the universe. Tardigrades themselves might even be an alien life form.

That is real gift that tardigrades give us. Through their survival of nearly everything, including all 5 mass extinction events so far on earth, through their uncountable numbers on earth, and through their ability to travel in space tardigrades provide strong evidence that we aren’t alone in the universe… And if you’re reading this in a mossy forest alcove you’re really not alone.


Friday, 3 October 2014

Wednesday, 1 October 2014

The Green Wall of China: How to Fight a Desert

Beijing is a pretty important place. China’s capital and largest city is not only home to over 21 million people, it is the seat of power for the world’s most rapidly developing country. Consider the fact that over the past 3 years China has used more concrete than the United States did in the entire 20th century and you can begin to understand how quickly the world’s most populous country is catching up to the west.

 All that development comes at a cost, however; and since the late 70’s Chinese officials have been hard at work fighting what they call the yellow dragon and the rest of us call the Gobi Desert. You see, overgrazing, deforestation, and drought throughout China have caused soils to erode and blow away, leading to the advancement of the Gobi and an intensification of the annual dust storms that pound Beijing and bring Asian dust particles (as well as pollution) across oceans to the west coast of North America.

This environmental degradation is not unheard of. Most people are familiar with the dust bowl that devoured over 4 million acres of the North American plains in the early 20th century. Those conditions were cause by exactly the same actions that have created the problems in China. Too many cows eating all the grass, the grass dying because of drought, top soil destabilizing because there are no plant roots to hold it all in place. Gradually the top soil blows away, with disastrous consequences.

So what can be done to stop a desert once it gets to marching? In the US the answer came in the form of a 100 mile (160 km) wide strip of trees running north to south through the country which reduced the amount of dust in the air by 60% in a few years. Since the 1970’s China has been hard at work building a forest of their own, the Green Wall of China.

The scale of the Chinese reforestation effort boggles the mind. While the UN estimates that only 2% of China’s natural forests remain intact, the country plans to plant enough trees to increase its forest cover to 42% by 2050. Over the past ten years alone, Chinese citizens have planted over 56 billion trees. Each year they plant twice as many trees as the rest of the world combined. So, is it working?

The results, it turns out, have been mixed. While China is now approximately 20% forest-covered those forests aren’t exactly as natured intended them to be. Apparently planters in the north have relied almost exclusively on poplar trees, people in the south have planted firs, and elsewhere forests are almost entirely eucalyptus. The practice of planting only one kind of tree is called monoculture, and it is very risky business.

A forest with only one kind of tree has a lot of the same problems as a baseball team where everyone is a right-handed batter. In the short-run they might win a few games but eventually they will come up against a left-handed pitcher and things will fall apart as we saw in our discussion of left-handed people. Likewise, a monocultured forest might look alright at a glance but if a disease finds its way in which effects one of the trees, it is likely to take them all down at once. This is exactly what happened in Ningxia in northwest China when in 2000 a pest wiped out over a billion trees representing 2 decades of planting.

Monoculturing isn’t the only problem facing the green wall. While the poplars protecting Beijing seemed like a great idea when they were planted (because of the fast growth rate and toughness of the trees) they are now dying off because they were all grown from cuttings, which have a shorter lifespan than trees grown from seeds (30 to 40 years versus several hundred).  

A solution to the problem might, ironically, lie in a plant that China devoted much of its energy to eliminating in the 80’s and 90’s called sea-buckthorn. Buckthorn is a shrubby bush that grows along river banks and was previously thought of as a pest because its root system burrows deeply into soil and is almost impossible to remove. That, however is a horticultural perfect trait for battling a desert. Mixed forests of sea-buckthorn and poplar have already shown a lot more promise than poplar forests alone. It turns out that using China’s native trees rather than ones chosen by planters might be the smarter way to go about things.

Reforesting China is not going to be easy. The northern part of the country is a lot more arid than places with successful reforestation campaigns like the US, Germany, and Siberia. In order to stabilize the Gobi, China will have to learn quickly that the solutions to its problems are more likely to be found along its own river banks and in its remaining natural forests than in the policies of other nations.