Friday, 30 August 2013

Sketchy Fact #4: A Really Big Bird

The largest flying bird to ever live – Agrentavis magnifens – had a wingspan of 23 feet. It’s wings covered an area of 87 square feet and it weighed about 170 lbs (78 kg). It had feathers that were a meter and a half (59 inches) long!

Wednesday, 28 August 2013

Evolution: How Come We Still Got Monkeys?

Have you ever wondered about the origins of humanity? Most people generally understand the idea of evolution and that people used to resemble our ape and monkey cousins more closely than we do now. But, to quote one of our readers who recently posted on the Sketchy Science Facebook page, if people evolved from monkeys “how come we still got monkeys?” To answer that question, we turn to one of the greatest scientists of all time. Mr. Charles Darwin.

Evolution is built on three basic ideas:

1)     It is possible for the DNA of an organism to change over time. A more scientific term for this change is ‘mutation.’
2)     Mutations can either be helpful, harmful, or do nothing in terms of an animal’s survival.
3)     Over time mutations accumulate and produce new species.

As we saw in the mitosis article a while back, cells replicate like crazy but every once in a while they make a mistake. Sometimes those mistakes happen at the level of DNA and lead to some change in the organism. If that change is something like a piece of inactive DNA getting a little bit shorter, that won’t really effect the life of the animal all that much. If, on the other hand, that change is something like a third arm or the ability to shoot lasers from one’s eyes, the environment might take notice.

It is the environment taking notice that drives evolution. This is called “natural selection.” If your third arm is super strong and helps you survive more effectively, you might live to have three-armed offspring. If your third arm just gets in the way and can’t do much, it might get caught up in some bushes while you are running from a lion. No freaky offspring for you. Over time, changes in a group of animals build up if they are helpful (or neutral) and can become the norm. Get enough changes built up, and the new animals might be so different from the old ones that they could be called a new species.

That’s all well and good, but it doesn’t answer the specific question posed in the title of this article. To understand that, we have to clarify something: No species that exists today evolved from anything else that is currently alive.

When scientists say that humans evolved from apes (or monkeys if you go back far enough), what they mean is that modern humans and modern monkeys share an ancestor. That’s kind of a tricky thought so let’s consider an example to help explain speciation (the evolution of new species):

Imagine a group of monkeys living in a valley. They have all the bananas they could want and enough room to throw their feces as far as their arms can manage. It’s monkey heaven. However, all good things must come to an end and one day a massive landslide cuts the population of monkeys into 2 groups. Now let’s imagine those groups don’t interact again for another few million years. They build up their own mutations and adaptations and split up on the evolutionary tree. If you waited long enough and then removed the barrier between them, you would have 2 totally separate species. One may have changed a lot, the other might have only a few slightly noticeable changes, but neither is the same as the original animals that lived in monkey heaven.

Sometimes species can go a really, really, ridiculously long time and change very little. Crocodiles have existed in pretty much the same form since the dinosaurs were worrying about being late for work, something like 240 million years ago. Humans have only looked like we do now for about 150,000 years. We were tree-swinging, feces-chuckers somewhere between 5 or 6 million years ago.

These different rates of change are why sometimes we hear people say things like “Humans evolved from monkeys.” We didn’t. That’s impossible unless you managed to freeze our monkey-like ancestors and thawed them out a few million years later, still alive. What those people mean is that monkeys look more like the common ancestor that we share with them than we do.

So, how come we still got monkeys? The reason is that monkeys haven’t had to change as much as we have to survive over the past several million years. The monkeys you see today aren’t the ones we evolved from, they just have more of a family resemblance.

Friday, 23 August 2013

Sketchy Fact #3: Can't Touch This

You have never actually touched anything. The negative charge of electrons that orbit every atom in your body repels the electrons of everything else with a force that is a billion billion billion billion times stronger than gravity (at that scale). Right now you are levitating a tiny fraction of an inch above your chair.

Wednesday, 21 August 2013

Fat Stingrays and Thinking Outside the Box

A little known fact about scientists is that they don’t always play nice with each other. Researchers in one field might disrespect or openly mock others in a field that they don’t view as up to snuff. Knight, and apparent wordsmith, Ernest Rutherford once famously said, “All science is either physics or stamp collecting.” Another gem comes from physicist Wolfgang Pauli who, after his wife left him for a chemically inclined colleague said, “Had she taken a bullfighter, I’d have understood. But a chemist!?” 

Clearly some scientists are witty jerks, but occasionally fields collide to produce some great and worth-while research. A perfect example comes from the work of Christina Semeniuk who, using her research as an excuse to visit the Cayman Islands (and who could blame her?), made it her mission to save a fever of stingrays (yes, a group of stingrays is called a fever) from the tourists who loved them too much.

Stingray City is a series of sandbars off the coast of Grand Cayman Island that is densely populated by marine life, including stingrays. The water is crystal clear, the sun is nearly always shining, and every year tourists jump at the chance to disembark from cruise ships and plunge into the water for a unique wildlife encounter. Anyone who has ever fed a stray cat can see the potential problem with this. The stingrays quickly pick up on the fact that if they tolerate being poked by a fat guy in a Hawaiian shirt for a few minutes, they get a free meal.

Dr. Semeniuk wanted to understand what kind of damage an influx of tourists could cause and use that information to come up with a solution. First, she used her natural science savvy to tackle the question of what effect the tourists were having on the rays. Her research revealed what you might expect: the rays were not only dangerously habituated to people, they were obese. Compared to a fever that had never seen a Hawaiian shirt, the Stingray City group was a pretty unhealthy lot. They even had an estimated death rate due to boat-collisions that was a little beyond what could be considered sensible.

So, what to do? A major problem with wildlife tourism is that, on the face of it, it is a lot better than exploiting nature. At least stingrays were not on the menu at the nearby resorts, right? Not necessarily. Unhealthy animals leads to an unhealthy ecosystem and, whether the cause is an oil spill or a Steve Irwin wannabe, an unhealthy ecosystem needs to be taken care of.

With that in mind, Dr. Semeniuk ventured into foreign territory for a marine biologist. She picked up her clipboard, wrote herself a survey, and tackled some social science. She asked the people who visited Stingray City if they would come back after an overhaul of the attraction’s rules. She presented them with different options and got them to select the ones they would visit. Some options had tonnes of rays, others not so many. In some scenarios they could touch and feed the rays, in others they watched from a distance.

She fed her data into a computer model that predicted each scenario’s impact both on the stingray population and the tourists’ willingness to continue visiting the attraction, and took her results to the people in charge. Since then, scientists and managers have been tweaking the rules governing tourists’ interactions with stingrays, to the benefit of the island’s economy AND its ecosystem.


The beauty of this research is that it contains a lesson we can all appreciate. Don’t be afraid to step out of your comfort zone. Go the extra mile. Learn everything you can. In the end, you will feel like a superstar and you can potentially make a lasting difference in the world. 

Special thanks to Dr. Christina Semeniuk for her co-operation in preparing this article! If you thought her research was as cool as we did, then check out her lab website here!

Friday, 16 August 2013

Sketchy Fact #2: Invertebrate Bloodbath

Octopi (or octopuses, if you prefer) bleed blue. They can also open jars. These two things probably don’t have anything to do with one another.

Wednesday, 14 August 2013

Where’s the Beef? The Mouth-Watering World of Lab-Grown Meat

Researchers at Maastricht University in the Netherlands have spent the past five years working to trade in their lab coats for chef’s hats, and the results might one day save the world.

The idea of lab-grown meat conjures up a lot of curiosity in the general public. Personally I imagine a factory-sized lab complete with polished white tiles as far as the eye can see and incomprehensible lab equipment (beakers, curly transparent pipes, liquids of every conceivable colour) bubbling away to produce shelves of pulsing steaks that line the corridors. The reality is far from that, but who knows what the future might hold?

Mark Post might. He is the team-lead on Operation Lab-Burger. Post and his colleagues have spent the past half-decade getting closer and closer to producing meat that is free of needless details like cows and pigs. On Monday, August 5, 2013 in London they unveiled the culmination of their work so far: the world’s first lab-grown hamburger.

It wasn’t exactly a value-menu option, coming in at a cost of $332,000 US, but the reviews were promising. Josh Schonwald, a Chicago-based journalist, was reluctant to judge the meal too harshly on account of it being free of ketchup, lettuce, and bun while Austrian nutritionist Hanni Ruetzler said it could use a dash of seasoning; but the pair agreed that the texture was about right.

The tasters’ biggest beef with the current offering is that it isn’t as juicy as regular meat. This is because it is pure muscle while a conventional burger is a mix of muscle and fat. Post is confident that allowing a certain proportion of cultured tissue to form into fat cells would solve this problem and could even be healthier than cow-fat.

The researchers are more concerned with scalability than taste. Post’s team hopes to one-day see a real market based on artificially produced animal tissue. The dish served up last week, which was funded by Google co-founder Sergey Brin, represents only a step in the right direction.

The race to produce the world’s first commercially viable cultured meat is fueled by the need to feed a growing global population that increasingly demands a western diet high in animal protein. Experts anticipate that the global demand for meat will double in the next 40 years. Since the land devoted to raising animals for slaughter takes up something like 70% of all agricultural land on Earth, lab grown alternatives are a much more desirable option. Even PETA co-founder Ingrid Newkirk is singing the praises of Post’s team saying, “As long as there's anybody who's willing to kill a chicken, a cow or a pig to make their meal, we are all for this.”

The meat, or “shmeat” as the researchers have taken to calling it, that was dished out in Monday’s demonstration was grown using muscle tissue from the shoulders of two organically raised cows. The cells collected from the cows were placed in a nutrient rich solution and grown into the 20,000 strands of tissue that were pressed together to make the burger. The researchers weren’t blind to the importance of presentation, however. They used red beet juice and saffron to take the beef from a pale yellow to a richer red colour, correctly assuming that people wouldn’t want to eat something that looked like it had jaundice.

The major hurdle for shmeat will be getting people to stop thinking of it as “fake-meat” and increase public willingness to eat it. Publicity stunts like last Monday’s tasting are a great way to get people engaged and talking, which is half the battle.

Whether or not lab-grown meat is a viable option for the world is still uncertain. $332,000 is a lot to pay for a dry, bland, burger. However, if the day ever comes when McDonalds starts offering up a shmeat-based Big Mac, the Sketchy Science team will be at the front of the line, salivating like a puppy in Pavlov’s Bell Shop. Eager to do our part for the environment in the most mouth-watering way possible.

Friday, 9 August 2013

Sketchy Fact #1: The Grizzly Bolt

Usain Bolt can run 100m in 9.58 seconds. A grizzly bear can do it in seven and a half. Don't try running from grizzly bears.

Wednesday, 7 August 2013

On Second Thought: How do we define time?

The story behind standard units of measurement is like TED Talks meets Jerry Springer. Very smart people have gotten very worked up about these seemingly obvious ideas for a long time. You don’t need to look any further than the United States’ stubborn use of imperial units to understand that once someone has an idea about measurement, they tend to stick with it until long after it stops making sense.

As much as I would love to expound on how every unit of measurement came to be set, I understand that you came here to read a blog and not a textbook. With that in mind, let’s set our gaze on the most comprehensible, familiar, and seemingly least arbitrary unit of measurement: the second.

Ask a third-grader what a second is and you might get a reasonably astute answer. Something along the lines of: “It is a piece of time.” Move up the academic echelon and things would get predictably more advanced. You would find out that it is one sixtieth of a minute, which is itself one sixtieth of an hour. An hour is one twenty-fourth of a day, and a day is how long it takes for the Earth to complete one full spin on its axis.

At this point we have gotten to the real heart of the matter. A second is a description of something real and meaningful that happens in nature – the rotation of the Earth. The problem with this definition of a second is that the Earth is less like a well-oiled machine than it is a mostly reliable but occasionally flaky roommate. The rent might get paid on time, but they have a bad habit of leaving windows open.

You see, the Earth doesn’t spin at a constant speed. It speeds up and slows down in ways that we don’t completely understand. A current day is roughly 24 hours long, but if you hopped in your Delorian and went back to the Triassic (220 million years ago) it would only be 23.5 hours. Go back a little (actually a lot) further to the Middle Cambrian 510 million years ago and you would only have 20.7 hours to get your errands run. But even that isn’t as bad as in the frigidly named Cryogenian Period of 900 million years ago when a day was a resoundingly speedy 18 hours.

The upshot of this inconsistency is that a second loses all meaning if we anchor it to the spin of the Earth. Scientists don’t like using units that don’t have meaning so since they realized that the Earth wasn’t cooperating, they have had to get creative.

For a long time (from AD 1000 until about 1960) the best they could come up with was saying that a second is 1/86,400 of the mean solar day. Unfortunately the “mean solar day” is just a fancy way of saying 24 hours and since we know that 24 hours is just a meaningless number, this definition doesn’t represent any actual improvement beyond sounding satisfyingly technical.

A better definition would incorporate something that is really and truly constant. Fortunately, there are a couple things that fit the bill. The best and most Star Treky is the speed of light. The cool thing about the speed of light is that it is the same everywhere in the universe (as long as you shoot your beam through a vacuum). Starting from there and following a few quick and painless calculations we could define a second as the time that it takes light to travel 299,792,458 meters in a vacuum.

That is a pretty good definition. It is precise, objective (if you ignore the definition of a meter which has something to do with a fraction of a line of longitude running through Paris), and easy to understand. The problem is, you can’t exactly measure it… The number of meters is just way too big.

We are almost there, though! I promise. We have all the ingredients we need for a solid definition of a second. We just need something constant that we can measure without building a lab that is bigger than the distance from the Earth to the moon. Enter atoms.

Atoms are great because they are as reliable as they are tiny. At a constant temperature and constant pressure atoms vibrate at measureable and consistent speeds. That is why the building blocks of matter are what scientists currently use to define a second. Next time someone is pestering you do to something and you want to tell them you will do it in a second, trip them up completely and say something like “Yeah, I’ll get to it in the time it takes an atom of Cesium 133 to oscillate 9,192,631,770 times!”

Assuming they don’t clue in that it took you longer than a second to say it (and if they can resist the urge to beat you up), you will have taught them something about the collision between the familiar and the strange. And THAT is what seconds are all about.