T is for Tardigrade

By Jonathan Farrow from the Thoughtful Pharaoh 

Boil ’em, mash ’em, stick ’em in a stew.¬† They’re versatile!

No, I’m not talking about taters. ¬†I’m talking about tardigrades: quite possibly the most durable¬†creatures on Earth.

They might also be the strangest combination of cute and terrifying anybody has ever seen looking through a microscope.

Cute and terrifying.  Image by Abribus
Meet the water bear.  Strange combination of cute and terrifying. Image by Abribus

Tardigrades, also known as water bears, evolved 500 million years ago. ¬†They have survived on a diet of moss and lichen since around the time¬†the first fish evolved and shortly after animals evolved at all. ¬†While their basic body plan hasn’t changed much, they haven’t been evolutionarily idle. ¬†They’ve developed some pretty neat¬†adaptations (some of which will be discussed below) and diversified into over 1000 unique species. One thing all¬†of these species¬†has in common is size: all species of tardigrade¬†measure¬†between 0.1-1 millimetre (comparable to the size of a single salt crystal).

The amazing thing about these itty-bitty balls of chitinous cuticle is that they can withstand pretty much every type of extreme we can cook up. ¬†They’ve been boiled to over 150 degrees celsius without breaking a sweat. ¬†They’ve been frozen to -250C and didn’t need tiny parkas. ¬†They’ve been dipped in acid, shot into space, dried out, and zapped with thousands of times the lethal radiation dose for a human and they just kept chugging.

Why won't you die!? Image by Frank Fox
Why won’t you die!? Image by Frank Fox

Why are we being so cruel to these tiny creatures?  Because they keep surviving.  Things that terrify us and would kill almost any lifeform barely even faze them.  Tardigrades have expanded the notion of habitable environments and understanding their indestructibility has profound implications for both earthbound medicine and for life on other worlds.

I think tardigrades are pretty darn cool.  This is likely due in no small part to the fact that the lab where I did my thesis in undergrad was home to a healthy colony of moss-eating tardigrades.  Up on the third floor of the Life Science Building at McMaster University, my former supervisor, Dr. Stone (or Doc Roc as he likes to be called) has been testing tardigrade tolerances with Taru, his PhD student.

“Ewww, you can see all of its insidey bits” – Me, the first time I looked at a tardigrade through a microscope. Image by Daniel Adrian Ciobanu, Krzysztof Zawierucha, Ioan Moglan, and ŇĀukasz Kaczmarek.

I got in touch with Doc Roc this week to ask him a few questions about tardigrades. ¬†To give you an idea of the kind of (awesome) professor he is, one of his research goals was to publish a one-sentence paper. ¬†He accomplished that goal with the help of quite a number of semi-colons. ¬†As you’ll see below, I think he likes that useful but oft-forgotten punctuation mark.

Thoughtful Pharaoh (TP): Where do you find tardigrades?

Doc Roc (DR): Tardigrades are found the world over, literally on all continents and in all bodies of water; they inhabit all systems, marine, freshwater, terrestrial; they occur terrestrially on moss.

[They’re everywhere!]

TP: What have you done to test the limits of tardigrades?

DR:  We have tested their tolerance to temperature (cold), radiation, desiccation, pH, g-forces (simulated), and red food dye (I think that you know the tale); we have witnessed complete revival from -80 degrees Celsius for up to 6 months (but they can tolerate -250 K); 4000 Gy radiation (6 Gy kills humans); completely drying out inside an evaporating water droplet (tales in the literature purport over 100 years in a desiccated state); over 16000 g (Earth atmosphere being 1 g Рmeteoritic impact being an order-of-magnitude greater, however); and sensitivity to red food dye.

[The tale of the red food dye: In one of many discussions of tardigrades in that lab, I was asking if these incredible creatures had any weaknesses.  Doc Roc told me about a curious incident that happened when he tried to stain tardigrades to see them better.  He tried putting some red food colouring onto the plate and they changed colour and were easy to spot, but they also all died. Green and blue food colouring did nothing, but red colouring stressed the tardigrades to death.  Strange that such an indestructible creature could be undone by food colouring.]

TP: What is the most interesting thing about tardigrades, in your opinion?

DR: I think that understanding how their tolerance and reproductive modes (e.g., parthenogenesis) evolved are the most interesting topics for tardigrade research.

[Tardigrades don’t need males to reproduce. ¬†Females can lay unfertilized eggs which will hatch as clones, genetically identical to the mother. ¬†The advantage of this is that they don’t need to waste time looking for mates. The disadvantage is low genetic diversity.]

TP: What do you want to do next?

DR: We plan to investigate how they tolerate the high radiation doses (e.g., their DNA repair mechanisms).

[McMaster has a small nuclear reactor on campus, which has been used in recent years to expose tardigrades to high levels of radiation.  After thousands of times a lethal radiation dose for humans, the tardigrades were fine and in some cases the irradiated ones did better than their lab-housed control counterparts.  How they can survive and continue to reproduce remains a mystery but it almost certainly involves some incredible DNA repair.]

TP: Do you ever name the tardigrades?

DR: The student who studies them is named Taru, which seems an appropriate name for one; given that we work with a parthenogenetic species, I would name them Tarugrade 1, Tarugrade 2, …

[Seems reasonable to me.]

TP: If they’re so invincible, why haven’t tardigrades taken over the world?

DR: Organisms are limited in their resources, so populations can grow unchecked only to the extent that living materials are available (populations crash thereafter); predators additionally can reduce population sizes.

[In other words, tardigrades can still starve and get eaten.  Just like every other creature.]

TP: What can studying tardigrades tell us about life on other planets?

DR: Studying tardigrades can inform us about the limits to which organisms can survive, helping researchers to identify which extreme environments are viable and whether organisms could be transported between planets.

[The theory that life arrived here from another planet (called panspermia) is not as crazy as it sounds.  I wrote a bit about it a while ago.]

Thanks Doc Roc!

If you have any other tardigrade questions, feel free to comment below and be sure to share this with your friends. Spread the water bear word and let us not be frightened of our tardigrade overlords!

Tardigrade 1
This guy looks like he’s ready to partygrade. Image by the Goldstein lab.

If you want to learn more:

  • The BBC recently published a pretty comprehensive article about these resilient little critters here
  • TARDIS was a European mission in 2007 to see how well they survived in space
  • A (bearded!?) Hank Green produced a video about them for SciShow in 2012.

S is for Simple Rules

By Jonathan Farrow from the Thoughtful Pharaoh

Consider the following: schooling fish, roundabouts, segregation, and human consciousness are all examples of the same fundamental property of the world.  It may seem crazy to suggest that roundabouts may be interesting in some sense, but bear with me.

The property in question, and this week’s topic, is emergence. ¬†In each case individual entities, by following simple rules, can create complex patterns of behaviour. ¬†What makes these patterns special is that they can’t be predicted based on the simple rules alone.

Swarms

If you’ve ever seen a murmuration of starlings, you have probably found yourself wondering how that many birds (upwards of 100,000) can all fly so quickly in such close proximity without hitting each other. ¬†For those of you uninterested in ornithology (the study of birds), there are also plenty of examples of swarms in entomology (the study of insects) and ichthyology (the study of fish), and even¬†chiropterology (study of bats).

Image by SteveD
Image by SteveD

In each case, the animals are unaware (and frankly, uncaring) of the beautiful shapes their swarms make. ¬†They aren’t even trying to swarm. ¬†They are trying to survive and their instinct tells them to follow a few simple rules. ¬†Since the advent of computers, scientists have been trying to find out what those rules are.

One of the most famous computational models of swarming behaviour was proposed by Craig Reynolds in 1986.  In his Boids program, simulated birds had to follow three rules:

  1. Separation:¬†Don’t crash (steer away from nearby boids).
  2. Alignment: Get with the program (steer towards the average heading of nearby boids)
  3. Cohesion:¬†Don’t get lost (steer towards the average location of nearby boids)

This model is actually a really good model for the behaviour we observe in birds and fish.  Recent studies have also shown this alignment rule is especially important for bats.

Locusts, on the other hand, seem to have a much simpler set of rules.  Locusts just want to avoid getting their backsides eaten.  When approached from behind, locusts will tend to fly forward for fear of cannibalism.  This creates an overall tendency to move forward and can lead to giant swarms.

Image by CSIRO
Image by CSIRO

Roundabouts

If you’ve ever been to Swindon (and, from what I hear, you’re not missing much if you haven’t), you might have come across quite possibly the most offensive piece of civil engineering in the UK.

That's right.  A giant roundabout.  Image in the public domain
That’s right. A giant roundabout. Image in the public domain

As a North American, I cringe at the thought of even a tiny roundabout but Swindonians apparently hate everything that is good in this world.

They built the Magic Roundabout. ¬†A terrifying series of 6 small roundabouts encircling a larger roundabout that goes the other way. ¬†If that sounds confusing, it’s because it is.

The more confusing part, however, is that hundreds of thousands of cars pass through it unscathed.  While there is certainly a lot of anxiety about it, there have been only 14 major accidents in 25 years.

Hell for North Americans.  Image from the BBC
Hell for North Americans. Image from the BBC

The vast majority of people pass through fine, despite there being 5 different entry and exit points and many conflict points (places where streams of traffic cross).  This happens because of a few simple rules:

  1. Follow the lines
  2. Give way to cars coming from the right
  3. Drive to where you want to go
  4. Don’t crash

Apparently it’s actually an effective way to move cars through an intersection, but my North American sensibilities just can’t handle it.

For more information on this piece of crazy road engineering, visit this explanatory page and watch this video.

Segregation

Choosing¬†who you associate with based on a singular trait has been known to lead to a lot of issues in the past. ¬†As a dog person, I’ve lost a lot of friends to cats (and their parasites). ¬†Despite my friendly demeanour and my ability to put up with a fairly large proportion of cat-lovers in my immediate vicinity, at a certain point I start to feel uncomfortable and want more fellow dog-lovers.

Tensions flare.  Image by Peretz Partensky
Tensions flare. Image by Peretz Partensky

In 1971, Thomas Schelling set out to model this behaviour and came out with a somewhat surprising and scary result. ¬†Even when people are fine with being in the minority, if they are dissatisfied when surrounded by a large majority of “others”, they will tend towards segregation. ¬†The model followed a few simple¬†rules:

  1. If you are surrounded by a certain percentage (e.g. 30%) of similar people, you are satisfied
  2. If you are surrounded by a certain percentage of different people (e.g. 70%), you are dissatisfied
  3. If you are dissatisfied, move to somewhere where you are satisfied.

Within a few rounds, there is very little diversity left as people¬†tend to move towards those who are similar. ¬†This, despite the fact that no individual is saying they outright dislike the other group or couldn’t live with members of the¬†other group. ¬†This model helps to explain why segregation is so hard to eliminate.

Interestingly, this tendency towards segregation can be reversed if a maximum of similar people rule is added:

4. If you are surrounded by a certain percentage of similar people (e.g. 90%) you are dissatisfied

Again, complex patterns and simple rules.

To learn more about the model, go here.

Conciousness

There are approximately 100 billion neurons in an adult human brain.  These neurons are connected in intricate ways to create an estimated 100 trillion connections.

Now that's a lot of connections!  Image from Wikimedia
Now that’s an impressive set of connections! Image from Wikimedia

Somehow (and to be honest we’re not really sure how yet), these connections lead to all of our brains’ activities from thought to imagination and¬†memory. ¬†The abilities of the system (the brain) couldn’t possibly be known from the rules that neurons abide by. ¬†All that a neuron does is pass on its signal according to a set of rules. ¬†We still don’t know what those rules are.

We do know that when a neuron is activated (whether by electrical or chemical stimulation), it activates other neurons.  The precise number and location of these other neurons is still a big mystery in neuroscience, but it must be activating both nearby neurons and neurons on the other side of the brain.  This dual activation of long- and short-distance connections is what creates the sustained patterns we observe in fMRI scans.

Human Connectome Project
The¬†Human Connectome Project, kind of like the Human Genome Project before it, is setting out to map all of the brain’s 100 trillion connections to better understand how it works. ¬†Image by Xavier Gigandet et al.

While I don’t mean to suggest that everything in life can be boiled down to simple rules, I think it’s pretty incredible the patterns¬†that emerge from individual actors all playing their parts.

R is for Ratzilla

An excerpt from my favourite scene in the 1987 film, the Princess Bride:

Westley:¬†Rodents of Unusual Size? I don’t think they exist. [R.O.U.S.¬†attacks Westley] Westley:¬†Ahhhh!!!

Why is that my favourite scene?  Because I laugh every time I watch it. The R.O.U.S. is just so ridiculous-looking and shows up right after Westley disbelieves its existence.

For the devoted readers out there, you’re maybe wondering what my obsession with R.O.U.S.es is, because I’ve written about them¬†before, but somehow they capture my imagination unlike any other strangely-proportioned creature. ¬†I think it has something to do with the comedic effect of reversing¬†the expectation of something cute.

Rodents of Unusual Size: They do exist. Image from the Princess Bride
Rodents of Unusual Size: They do exist. They are definitely not cute.  Image from the Princess Bride

The R.O.U.Ses from the Princess Bride have come to set the standard for overgrown rodents, but sometimes reality is stranger than fiction.

The largest discovered member of the rodent family (membership to which depends on having a pair of razor-sharp, ever-growing incisors), Josephoartigasia monesi is estimated to have been the size of a bull.

.

Reconstruction of head
A reconstruction of J. monesi’s¬†skull based on the bones that were recovered. Image by Andres Rinderknecht & Ernesto Blanco

Since only its skull was discovered, the¬†¬†weight of this creature has been debated. ¬†The original discovery paper pegged the mass of the monstrous mulch muncher at 1211kg on average with a maximum of 2584kg. To put that into perspective, that’s anywhere from 1 to 4 dairy cows. ¬†A more recent study, however, showed that depending on the part of the skull you use to predict the mass of the full creature, J. monesi¬†could have weighed from as low as 356kg (half a cow) to 1534kg (back up to the 2-cow range). ¬†Even if the creature was as small as 356kg, that still makes it nearly 6 times heavier than the current rodent heavyweight champion of the world, Floyd Mayweather the capybara.

In any case, it’s definitely big enough for a recent¬†Science Magazine article¬†to correctly use¬†the term “Ratzilla”.

Rodents of Unusual Size: They do exist.  Image from the Princess Bride
RATZILLA!!!  Image by James Gurney

Ratzilla’s bite force was recently estimated up to 4000N, enough to outperform modern crocodiles and tigers. ¬†It was definitely a herbivore though, and is thought to have used its teeth as elephants use their tusks: to dig around for tasty treats.

Luckily for us, Ratzillas (Ratzillae?) no longer roam the plains of South America.  They went extinct about 2 million years ago, after 2 million years of rodent dominance.  Interestingly, that makes them the contemporaries of terror birds, sabre-toothed cats, and giant ground sloths. Their size and sharp teeth probably made them tough prey items.

Just like the R.O.U.Ses in the Princess Bride though, they were probably susceptible to fire jets and swords.

And with this rodent rant written, I promise to not write about any more Rodents of Unusual Size for the remainder of this ABCs series.

Q is for Quokka

What’s half a metre long, weighs 3-4kg, and has the cutest face you ever did see?

Cat_Cute
Image by Gaurav Pandit

Nope, cuter.

Cute_beagle_puppy_lilly
Image by Garrett 222

Even cuter.

Quokka Cute
Image by Jin Xiang

Yup, there it is! ¬†This, dear readers, is a quokka. ¬†A native of South west Australia, this marsupial has recently skyrocketed to fame because of the way¬†its mouth seems to rest in an adorable little smile. ¬†A quick Google image search will reveal hundreds of awesome pictures (that aren’t licensed under creative commons) and a growing number of quokka selfies. ¬†It looks so happy that it has even been dubbed the mortal enemy of Grumpy Cat.

So, what’s the deal?

The quokka is a vegetarian (one of those darn salad-eaters) that prefers leaves and stems.  Since its habitat is so dry, it will swallow its food whole only to regurgitate it later, chew it up, and swallow again in order to make sure it sucks out all of the moisture.  Their digestive systems are tuned to allow survival in the dry climate of Western Australia.  This means that when humans try to feed the quokkas with bread or give them water, the poor animals can go into toxic shock and die.  For the love of all that is cute in this world, do not feed quokkas.

I'm fine with my flower.  I don't need your charity! Image by Vicsandtheworld
I’m fine with my flower. I don’t need your charity!
Image by Vicsandtheworld

Like other marsupials, quokkas have a very short pregnancy¬†of only one month, followed by five¬†or six¬†months of pouch-time. ¬†Unlike most other marsupials, quokkas have the ability to double down on their reproduction. ¬†The day after giving birth and moving the joey to their stomach pouch, female quokkas will mate again and will pause the development of the new foetus in a process known as embryonic diapause. ¬†If the joey in the pouch doesn’t make it (quokka-god forbid), the female can resume the embryo and still call the season a reproductive win.

One thing the quokka’s PR people (who have done an excellent job so far, by the way) might not want you to know is that female quokkas, when threatened by predators, will quite literally throw their babies under the bus. ¬†They will eject their joey and head for the hills, hoping that the predator takes the easy prey and they get to live another day.

Image by Hesperian
A nice, happy quokka family. ¬†That obviously didn’t resort to infanticide in the case of this joey. ¬†Doesn’t Nature just suck sometimes? ¬†Image by Hesperian

For the readers out there still keen to snap the perfect selfie, the best place to find quokkas is¬†on Rottnest Island, a tiny, 19km2 bit of land off the coast of Perth. ¬†[Non sequitur –¬†I can’t help but hear “Purse” said with a lisp whenever I come across Perth.] ¬†The island was named Rottnest (Rat’s Nest) by a dutch explorer who thought the resident quokkas looked like “a kind of rat as big as a common cat”.

Just like the selfie stick we know is lurking out of the frame of all those hilarious pictures,¬†disaster may be around the corner for the quokka. ¬†The¬†Australian Government¬†rates the Rottnest Island population as stable, but the quokka’s mainland habitats are under threat from foxes (an invasive species) and forest clearing. ¬†These threatened mainland populations are especially important because they contain much more genetic diversity than the island groups. ¬†The IUCN classifies the quokka as Vulnerable, one step above Endangered. ¬†This is due not to the population size (upwards of 10 000), but rather to the extremely small range and susceptibility to environmental change.

The quokka's range is quite limited.
The quokka’s range is quite limited.

The quokka is a species of very cute and biologically strange marsupial whose Australian home is under a myriad of threats.  Why the internet is currently abuzz with it remains a mystery, but there are certainly some adorable pictures to be taken and some interesting things to be learned.

P is for Plant Defences

plant defences rising ape

By Jonathan Farrow of the Thoughtful Pharaoh

As the great glam metal band Poison sang in 1988, “Every Rose Has Its Thorn“.

Like so many glam metal bands to grace the world’s stages before them,¬†none of Poison’s members were botanists. If they were, they might have known that roses actually have prickles, not thorns.

It’s an easy enough mistake to make. ¬†But because I am a pedant at heart, I want Poison to know that, technically, thorns¬†are¬†modified branches, spines are modified leaves, and prickles are modified skin. That means roses have prickles. I therefore petition that the lyrics of the chorus of the song be changed from:

Every rose has its thorn
Just like every night has its dawn
Just like every cowboy sings his sad, sad song
Every rose has its thorn

to the more scientifically accurate:

Every rose has its prickle
Just like brine turns veggies to pickles
Just like every cowboy is really quite fickle
Every rose has its prickle

Thorn (modified branch) from a citrus plant.
Thorn (modified branch) from a citrus plant. Image by Edgovan22
Spines (modified leaves) from a Pereskia grandifolia (aka rose cactus) plant
Spines (modified leaves) from a Pereskia grandifolia (aka rose cactus) plant  Image by Frank Vincentz
Rose_Prickles
Prickles (modified skin) from a rose bush.  Image by JJ Harrison

But how did plants come to develop¬†all of these different ways to impale gardeners’ fingers in the first place?

To answer that question, let’s imagine a world without thorns, spines, or prickles. No toxins, sap, poisons, or deterrents of any kind. ¬†In a world like that, as long as there were herbivores, plants wouldn’t last long. ¬†They’d get eaten up pretty quick and getting eaten generally isn’t good for your reproductive health (with a few noticeable exceptions *cough* black widow spider¬†*cough*). ¬†So there’s a lot of evolutionary pressure on plants to develop ways to avoid becoming lunch.

Predation from salad-eaters¬†isn’t the only pressure on plants, though. ¬†They also need to compete with other plants around them by growing to capture more sunlight and they need to devote resources to reproducing. ¬†This is called the growth-differentiation balance. ¬†Plants, with limited resources, must choose between straightforward growth and developing specialized defences. ¬†If this theory is¬†true, we would expect plants that didn’t have to worry about getting eaten would be less thorny. ¬†In October 2014, an international team of researchers showed that in an herbivore-free zone, like the favourite hangouts of leopards on an African savanna,¬†non-thorny plants thrive, whereas the thorny plants do best in the favourite hangouts of salad-eating impalas.

Salad-eaters (aka herbivores) don’t just take an evolutionary backseat to this escalation¬†of plant defences. ¬†Ever since the first animals¬†started emerging from the sea and started choosing¬†salad, plants have been trying¬†to send them back and animals have kept coming. ¬†It’s an evolutionary arms race.

And if the Cold War taught us anything, its that arms races lead to some pretty ridiculous specializations.  Here are a few of my favourites on the plant side of things:

Sorcerer Corn

Behold! Sorcerer Corn!  Image by Silverije
Behold! Sorcerer Corn! Image by Silverije

It looks like regular corn. ¬†And that’s because it is.

Regular corn seedlings, when exposed to a chemical in the saliva of beet armyworms, will release a chemical that summons a cloud (or, less dramatically, attracts) parasitoid wasps which will lay eggs inside of the armyworms.  These eggs will hatch after two days and eat their way through the armyworm from inside out.

Corn isn’t the only plant that releases signals like¬†this. ¬†In fact, you know the smell of freshly-cut grass? ¬†That turns out to be the plant equivalent of¬†screaming out to any relatives in the area to “GET READY! THERE’S SOMETHING THAT WILL HURT YOU NEARBY!”

Flinching Flowers

We normally think of plants as stationary things, unable to move.  This is usually true, but there are some plants which have the ability to quickly shut their flowers or droop on contact.  The most famous example of this is the Venus Flytrap, but that is more of an offensive flinch.

Image by Mnolf
Image by Mnolf

Mimosa pudica, or the sensitive plant, also has this flinching (thigmonastic) ability.  When touched, this species will close its flowers and fold away its leaves, thus decreasing its surface area and making it harder to see and eat.

I'm just going to fold away now...
I’m just going to fold away now… ¬†Image by Hrushikesh

Whether its by developing thorns, spines, prickles, the ability to fold up, or the ability to call helpful predators, plants have not been idle in the fight against salad-eaters. ¬†Every rose has its¬†prickles (not thorns!)¬†because of this ancient struggle and while they may be annoying, I guess we should be happy roses¬†haven’t evolved to attract parasitoid bears that will leave cubs inside of our stomachs to gnaw their way out over the course of a week.

Yet.

O is for Ocean Acidification

By Jonathan Farrow from the Thoughtful Pharaoh

We all know that CO2¬†emissions are warming the planet. ¬†Or at least,¬†most of us¬†do. ¬†What often goes unreported is the effect of carbon dioxide on the worlds’ oceans. ¬†A lot of the CO2¬† that we pump into the air makes its way to the water and is making it more and more difficult for shelled creatures like sea urchins, lobsters, and coral to survive.

Lobster
This is Bob the lobster. This is his “I’m sad because of the increased levels of anthropogenic carbon dioxide that are making my life harder” face. ¬†Image by Pedrosanch

In order to understand why this happens, we need to go back to secondary school chemistry.

Don’t worry, I’ll make sure Jared doesn’t pick on you.

Jared
No Jared! No!     Image public domain

The first lesson we need to recall is about acids.  What is an acid?

Something that bubbles in a flask?  Image by Joe Sullivan
Something that bubbles in a flask? Image by Joe Sullivan

Acids are compounds that have free hydrogen ions floating around. ¬†These hydrogen atoms are quite reactive, so it means the more free hydrogen you have floating around, the more reactive your compound. Acidity is usually measured in pH, which stands for the “power of hydrogen”. ¬†pH is measured on a scale (creatively named the “pH scale”) that ranges from 0 to 14.

Compounds that get a 0 on the scale are exceedingly acidic, meaning they are made up of pretty much just free-floating Hydrogen ions. Compounds that rate 7 are perfectly neutral, like distilled water. Compounds on the other end, near 14, are called “basic” or “alkaline” and instead of having lots of hydrogen ions to give away, they have all sorts of space for hydrogen atoms. ¬†This makes them reactive because they can strip hydrogen from things that don’t usually want to give it away (like Edward Norton’s hand in Fight Club).

The other confusing bit to remember is that the pH scale is logarithmic, meaning that each number you jump actually indicates a multiplication by 10. For example, something with pH 3 (like soda) is 100 times more acidic than something with pH 5 (like coffee).  This means if a large body of water (like the ocean) shifts by even a small pH number, the effect can be very large.

Image by OpenStaxCollege
Image by OpenStaxCollege

The second lesson we need to recall is about equilibrium.

In chemistry, everything tends towards balance. If you combine equally strong acids and bases, they will react together until the result has a pH that is in between.  You might also get a volcano-themed science fair demonstration.

When CO2 combines with water (H2O), they form carbonic acid (H2CO3).  The carbonic acid will break up (dissociate) into bicarbonate (HCO3) and a hydrogen ion (H+).  In a basic environment, the bicarbonate will dissociate further into carbonate (CO32-) and the result will be two hydrogen ions (2H+).

We can visualize this path with a chemical equation:

H2CO3¬† —- ¬† H+ + HCO3– ¬†¬†—- ¬† 2H+ + CO32-

Where this path stops depends on the environment it is in.  In an acidic environment, the balance will tend towards the left, with more hydrogen bound up with the carbonate (because there is no space in the solution for more free hydrogen).  In a basic environment, the balance will tip to the right, releasing more hydrogen and freeing up the carbonate.

Currently, the pH of the ocean sits at about 8.1 (slightly alkaline). ¬†Because of this, there is plenty of carbonate available for creepy-crawly-shellfish to use to build their homes. ¬†Crustaceans and corals combine the free carbonate with calcium to form calcium carbonate (aka limestone, chalk, and Tums). They can’t use bicarbonate (HCO3) or carbonic acid¬†(H2CO3) and find it hard to form anything at all in an acidic environment.

This means that as we add CO2 to the water, we create more carbonic acid and contribute to the acidity of the ocean, dropping its pH.  Not only does this make it hard for the little guys down there trying to make a living, but it also endangers the big chompers that eat the little guys.

The ultimate big chomper.  This is what happens when you jokingly search for
The ultimate big chomper. This is what happens when you jokingly search for “chomper” on wikimedia.

A recent review¬†found that even under the most optimistic emissions scenario, the ocean’s pH is likely to drop to 7.95, affecting 7-12% of marine species that build shells. Under a high emissions scenario, the pH will go down to 7.8, affecting 21-32% of those species.

In order to keep track of the progress of this acidification, researchers from Exeter have proposed using satellites to monitor hard-to-reach bits of the ocean.

Regardless of the pace of the change, scientists agree one thing is certain: the oceans will become less hospitable for shell-builders.  The superficial impact of this for humans will be rising prices on shellfish, but there will be much deeper ramifications throughout marine ecosystems.

And I think we all know who is to blame.

Jared

Thanks Jared.

N is for Naming

By Jonathan Farrow of the Thoughtful Pharaoh

Next time you happen to be walking though the Chamela-Cuixmala nature reserve on the West Coast of Mexico, keep your eyes out for this parasitoid wasp:

Image from a paper by Alejandro Zaldívar-Riverón, Juan José Martínez, Fadia Sara Ceccarelli, and Scott R. Shaw
Image from a paper by Alejandro Zaldívar-Riverón, Juan José Martínez, Fadia Sara Ceccarelli, and Scott R. Shaw

Its scientific name is Heerz lukenatcha.  There is also a related wasp named Heerz tooya.  Who comes up with these things!?

Biologists, it turns out.

The current official naming system for animals is run by the International Commission on Zoological Nomenclature (ICZN).  This multi-national commission, based at the Natural History Museum in London, keeps track of all the rules as well as the accepted names.

[There are also separate codes for other types of organisms  Рsee this wikipedia page for a list of the codes and prepare to go down an Oryctolagus cuniculus hole]

Generally, the first person to find an organism, make sure it hasn’t been named yet, and submit a scientific paper naming it, will get to choose a name. ¬†While there is quite a bit of freedom, the ICZN does provide the following guidance: “Authors should exercise reasonable care and consideration in forming new names to ensure that they are chosen with their subsequent users in mind and that, as far as possible, they are appropriate, compact, euphonious, memorable, and do not cause offence.”

That guidance does get stretched sometimes…

Appropriate?

During a 1980 entomological expedition to the Andes, one member of the team kept shouting “sh*t man, f*ck!” every time something went wrong. ¬†I guess a lot of things went wrong, because before long the whole team started calling the expedition the SMF Expedition. ¬†When a new genus¬†of beetle was discovered, they named it Esemephe (pronounced SMF). ¬†They justified it to the ICZN by saying that it was a melding of the greek words essymenos (hurrying) and ephestris (mantle), but everyone else knew it was really a reference to SMF.

Not so compact, euphonious, or memorable

The longest accepted scientific name is Parastratiosphecomyia stratiosphecomyioides, a species of fly.  At 42 characters, its only three short of pneumonoultramicroscopicsilicovolcanoconiosis, the longest word in the English dictionary.

Straight up offensive

Some names were actually designed to be offensive.  Two paleontologists, Cope and Marsh, basically had a naming war at the end of the 19th century. Marsh seemingly struck the first blow, submitting Mosasaurus copeanus (-anus is a greek suffix meaning ringed).  Later, Cope named an extinct mammal Anisonchus cophater for all of his haters.  I guess he just wanted to shake it off.

This trend was repeated in the 20’s with swedes Elsa Warburg and Orvar Isberg. In 1925, Warburg named a trilobite¬†Isbergia planifrons,¬†after Isberg’s apparently flat forehead (an insult in Scandanavia). ¬†In 1934, Isberg retaliated with a mussel he named¬†Warburgia crassa,¬†after Warburg’s girth (crassa=fat).

Just funny

Sometimes, biologists just feel silly.  Here are a few of my favourite scientific names, as a reminder that scientists can be funny.

There is a genus of fungus beetles called Gelae.  The species names are baen, belae, donut, fish, and rol.  Put those together and you get a whole bunch of tasty treats!  There is another genus of beetle called Agra, and one biologist in particular, Terry Erwin, has had a lot of fun over the years with some punny species names like cadabra, memnon, and vation.

Sometimes biologists go for the celebrity names, like a beetle named Scaptia beyonceae for the yellow fur on its behind or a fossil fly named Carmenelectra shechisme (pronounced Carmen Electra, She Kiss Me).  In 2013, Carmenelectra shehuggme was also added.

Other times, taxonomists like to make you read it a few times, like a moth named Eubetia bigaulae or a scarab in a large family named Cyclocephala nodanotherwon.

For hundreds of more interesting biological names, visit curioustaxonomy.net

M is for (exo)Moons

By Jonathan Farrow of the Thoughtful Pharaoh

With this post, rising-ape.com is now caught up with my website, thoughfulpharaoh.  From now on, I will be posting articles simultaneously on both sites, on Wednesdays.

Thanks to everyone for following along and as always, if there is a topic you have in mind, don’t hesitate to leave a comment below.

And now for this week’s article: exomoons.

There are 8 planets in our Solar System (sorry Pluto). ¬†Most of these planets have companions that follow them around, like obedient pets and criminal records. ¬†The total count of these moons is 181. ¬†We are all quite familiar with the big shiny one that orbits Earth (that may or may not be made of cheese), but what many people don’t know is the sheer number of¬†other¬†moons that exist in our Solar system.

Just like planets, these moons come in all different shapes and sizes. ¬†S/2009 S1 is only 400m across and orbits in one of Saturn’s rings, making it the very smallest moon. ¬†Ganymede, the solar system’s largest moon, measures in at about 5300km across, almost half the size of earth.

One of the biggest findings to come from¬†the Kepler mission is that most of the stars in the galaxy have planets. ¬†In other words, our solar system isn’t unique. ¬†That means our Solar System probably isn’t the only whose planets have moons. ¬†If our system, with 22 times more moons than planets, is any indication, there are a lot of moons to find.

This presents two immediate problems: firstly, why should we want to find them?  Secondly, how do we go about finding them?

Why find an exomoon?

The same thing that makes seawater rise and fall twice a day, tidal forces, can heat up a moon.  Tides are a result of the fact that the strength of the force of gravity is related to the distance between two objects.  On Earth, the water on the side close to the moon gets pulled out towards the moon stronger than the water on the other side, this creates bulges of water that move around as the earth spins: tides.

Tides stretch.  Image by Krishnavedala
Tides stretch. Image by Krishnavedala

The Earth is too small and our moon is too far away for much more than sea level change to happen, but Io, one of Jupiter’s moons, has over 400 active volcanoes¬†caused by extreme tides from the gravity of its host planet Jupiter. In this case, it’s not just bulges of water that are created, but bulges in the crust of the moon itself. ¬†This creates an immense amount of friction and heat.¬†Europa, another moon of Jupiter, gets enough energy to keep a planet-wide ocean of water liquid¬†under its icy crust. ¬†Some people think Europa might be habitable, even though it is so far away from the Sun.

If there are moons here in our Solar System that can be habitable at Jupiter-like distances,¬†there could be moons in other systems that orbit planets much closer, at Earth- or Mars-like distances. ¬†Some people, like Rene Heller at¬†McMaster University’s Origins Institute (a fine institution, if I do say so mystelf *full disclosure: I did my undergrad¬†there*), think exomoons might be our best shot for finding habitable places in the galaxy simply because of their abundance relative to planets (remember, there are 22 times more moons in our system than planets).

How to find an exomoon

This is the tricky part. ¬†It was hard enough finding exoplanets. Finding a transiting exoplanet is often compared to looking for the effect of a mosquito passing in front of a car’s headlight. ¬†In that analogy, finding an exomoon would be like finding out how many legs it has. ¬†No easy task.

It’s not impossible, though. ¬†Moons do have effects on their planets and if we look carefully enough, we can find them.

One way to find exomoons in transit data takes advantage of the fact that, viewed edge-on, a moon will appear more often at the edges of its orbit.

ExoMoonTransit
Image by Rene Heller

If you capture many transits over time, you can begin to see these wingtips in the transit data.

Image by Rene Heller
Image by Rene Heller

The grayscale bar in the image above represents the average effect of a moon orbiting a planet.  What astronomers can look for in the transit data is a preliminary dip (1) that starts off severe then levels off, followed by the regular planetary transit (2), followed by another characteristic dip (3) as the other wingtip passes in front of the star.

This method only works if you have a lot of data, but luckily Kepler was operational for four years and gathered just the right kind of data.

So now the search will begin. ¬†Who will find the first exomoon? ¬†And what if it turns out to be “no moon” at all?

An artist's impresison of a view from an exomoon with a triple star system.  Far out, dude.  Image by NASA/JPL-Caltech
An artist’s impresison of a view from an exomoon with a triple star system. Far out, dude. Image by NASA/JPL-Caltech

L is for Loch Ness

By Jonathan Farrow from The Thoughtful Pharaoh

Loch Ness, in the middle of the Scottish Highlands, has more fresh water in it than all the lakes and rivers in England and Wales combined.  It is neither the deepest lake in Britain nor the largest by surface area, but since it comes a close second in both categories, it claims the top spot for volume.  The loch is home to eels, salmon, and char and its shores support a healthy population of deer and waterfowl.  The area has historical significance as well, with Urquhart castle being instrumental in the war of Scottish independence.

Loch Ness, in all of its Google Map glory.  Not pictured: the monster.
Loch Ness, in all of its Google Map glory. Not pictured: the monster.

Despite all of this, when people read or hear “Loch Ness”, the next word they think of is almost always “monster”. ¬†This is a shame, because sadly, Nessie does not exist.

We know this for sure. ¬†There have been numerous, comprehensive reviews of the ‘evidence’ and a recent sonar survey of the entire loch failed to turn up anything even close to a giant sea monster. ¬†If Nessie is supposed to be a plesiosaur, you might think a population of giant, carnivorous sea creatures that somehow survived extinction and has been living in the same lake for 65 million years would make more of an impact on people in the region. ¬†There would be lots of stories about sea monsters, and old ones too. ¬†There aren’t really any credible mentions of this monster until the 1930s. ¬†No songs, folk tales, or myths, despite the area¬†being populated for thousands of years.

Not a sea monster, 1934.  Photo by Robert Wilson, published in the Daily Mail
Not a sea monster, 1934. Photo by Robert Wilson, published in the Daily Mail
Also not a sea monster, 1977.  Photo by Anthony Shiels
Also not a sea monster, 1977. Photo by Anthony Shiels
Still not a sea monster, 2012.  Photo by George Edwards
Still not a sea monster, 2012. Photo by George Edwards

My favourite little tidbit from my reading into the series of Nessie¬†hoax photographs is a photo of a supposed flipper which was used to name a new species in¬†Nature¬†in 1975. ¬†The scientific name of the Loch Ness Monster, according to Profs. Peter Scott and Robert Rines, is¬†Nessiteras rhombopteryx. ¬†I leave it up to the reader to decide if it is a coincidence that the name is an anagram for “monster hoax by Sir Peter S”.

The 1972 'flippers' in question.  Hard to see much at all, I think. Photo by Academy of Applied Science/Loch Ness Investigation Bureau
The 1972 ‘flippers’ in question. Hard to see much at all, I think. Photo by Academy of Applied Science/Loch Ness Investigation Bureau

While it is undoubtedly good fun to trash pseudoscience, the focus on the monsters of Loch Ness (or lack thereof) takes attention away from what I think is much more interesting: Loch Ness is part of the very same geological feature as the fjords in Norway, the hills in Newfoundland, the Gulf of St. Lawrence, and the Appalachian mountains in the southern USA.

Loch Ness is part of the Great Glen Fault, a crack in the Earth’s crust that runs in a straight line across Scotland, through the Irish Sea, and into Northern Ireland. ¬†This crack is very old, pre-dating even Pangea.

When two pieces of the Earth's crust slide against each other like this, it is called a transcurrent, or strike-slip, fault.  Image by Hellinterface
When two pieces of the Earth’s crust slide against each other like this, it is called a transcurrent, or strike-slip, fault. Image by Hellinterface

In fact, the process that brought the continents together into¬†the supercontinent of Pangea is the very same one that created mountains along this fault line. ¬†Back in those days, over 400 million years ago, the Atlantic ocean didn’t exist. ¬†As the plates of Baltica (modern-day Scandinavia and North-Eastern Europe) collided with Laurentia (modern-day North America and Greenland) and the small microcontinent of Avalonia (modern-day England, Wales, and parts of Northern France), bits of the crust were pushed up. ¬†This formed mountains.

As the plates collided, the highlighted area became raised.  The grey lines in this image are the current coastlines.  Image by Woudloper.
As the plates collided, the highlighted area became raised. The grey lines in this image are the current coastlines. Image by Woudloper.

Over time, the plates continued to move, and the Mid-Atlantic Ridge pushed Europe and North America apart, forming the Atlantic Ocean.  While Laurentia and Baltica are still around as the bases of the North American and Eurasian Plates, Avalonia was essentially spread to the winds.

Avalonia definitely got the roughest deal out of the three colliding plates. Image by Woudloper
Avalonia definitely got the roughest deal out of the three colliding plates.
Image by Woudloper

This is why, if you walk the Highlands of Scotland or the Appalachians, you will find the same rock types.  They were born in the same place in the same way, and have become separated by an ocean.

Loch Ness is an incredibly poignant way to visualize this separation because, just by looking at a map, you can see a crack in the earth.  If you look at the Northeastern part of Newfoundland, you can see the same crack with the same angle.

[For another explanation of this 400 million year old connection, watch this video by Tom Scott.]

Loch Ness is a wonderful place, not only for its natural beauty, but also for its geology. ¬†So do go visit, but don’t expect to find a monster.

K is for Kepler

“Truth is the daughter of time, and I feel no shame in being her midwife.”¬†Johannes Kepler

These words, written by Johannes Kepler in 1611, are profound.  At the time, Galileo had just discovered the Galilean moons (including Europa) in Florence but was being persecuted for his belief that the Earth orbits the sun.  Kepler, a staunch supporter of heliocentrism, was working as the Imperial Mathematician in Prague.  When word that Galileo had used a telescope to find the moons reached Kepler, he was so fascinated and impressed that he wrote an enthusiastic letter of support and scrawled that pithy aphorism.

While Kepler enjoyed some social status as Imperial Mathematician and was much more free to contradict Aristotle¬†than his Italian counterparts, his life was by no means a charmed one. ¬†The son of “an immoral, rough and quarrelsome soldier” (his own words), Kepler managed to carve himself a place in history¬†based on his skill as a mathematician and astronomer. ¬†He kept on working through many family disasters, including the deaths of his wife and his seven year old son and a witch trial about his mother.

Kepler was a devout Christian and grew up Lutheran but was excommunicated due to his rejection of the Augsburg Confession.  This left him neither a Lutheran nor a Catholic and between sides when the Thirty Years War broke out in 1618.

You've got to love that frilly collar.  Just like Shakespeare!  Actually, come to think of it, Kepler actually lived at the exact same time as Shakespeare.  I wonder if they ever met and what they might say to each other at a dinner party.  Image is public domain.
You’ve got to love that frilly collar. Just like Shakespeare! Actually, come to think of it, Kepler lived at the same time as Shakespeare. I wonder if they ever met and what they might say to each other at a dinner party. Image is public domain.

Despite all of this, Kepler revolutionized astronomy by formulating mathematical laws that accurately describe the motions of the planets. ¬†These are still taught in astronomy today and are called Kepler’s Laws.

The first law is that planets orbit in ellipses with the sun at one focus.  Before Kepler, most Western astronomers modelled the orbits of planets as circles and had to invoke a strange concepts like epicycles and equant points.

1. Planets orbit in ellipses, not circles.
1. Planets orbit in ellipses, not circles.  Image my own

The second law is that a line between a planet and a star will sweep out equal area in equal time. In other words, planets move faster when they are closer to their star and slower when they are further away.  This law is better understood with a diagram:

asd
2. Planets don’t have constant speed ¬†Image by RJHall

The third law, formulated after the first two, is that the time it takes a planet to make an orbit (orbital period) is directly proportional to its distance from the star.  This law allows astronomers to calculate how far a planet is from its star based only on information about the length of its year and the mass of the star.  Remember this one, because it will become important later.

As you can see, Kepler’s Laws are fundamental to our understanding of how planets move, or orbital dynamics. ¬†It will come as no surprise then that every young astronomer is all too familiar with Kepler’s laws. ¬†This isn’t the only reason he’s familiar though. ¬†He is also shares a name with the most successful exoplanet hunter the world has ever produced. ¬†The Kepler Space Telescope.

Kepler: Planet Hunter is kind of Like Abraham Lincoln: Vampire Hunter.  Except more real.  And frankly, a little more impressive.    Image by Wendy Stenzel at NASA
Kepler: Planet Hunter is kind of like Abraham Lincoln: Vampire Hunter. Except more real. And frankly, a little more impressive. Image by Wendy Stenzel at NASA

Launched in 2009, the Kepler Space Telescope used 42 image sensors to continuously observe over 145,000 stars. ¬†Unlike a lot of other telescopes that try to take magnified images, Kepler wasn’t interested in images. ¬†It wanted accurate data on brightness. ¬†It basically had a staring contest with these 145,000+ stars, waiting for them to blink. ¬†I say blink because Kepler was waiting for the brightness to go down and back up. ¬†The brightness of stars can vary for all sorts of reasons, but planets passing in front of their stars make the brightness dip in a particular way. ¬†This dip is called a transit and finding transits¬†was Kepler’s mission.

When a transit occurs, the size of the brightness dip corresponds to the size of the planet and the length of the dip corresponds to the time it takes a planet to orbit (as well as the size of the star). ¬†Remembering Kepler’s third law,¬†¬†if we know the time it takes to orbit, we can figure out the distance to the star. ¬†And if we know the brightness of a star and the distance, we can figure out how much energy¬†the planet receives. ¬†Plug all that in to a¬†simple(ish)¬†equation, and out pops temperature.

Stars, just like planets and people, come in all different shapes and sizes.  That means light curves also vary widely.   Image from Planethunters.org
Stars, just like planets and people, come in all different shapes and sizes. That means light curves also vary widely. Image from Planethunters.org, a great citizen science project that combines people’s natural pattern-finding ability with Kepler data to find planets.

So thanks to the Keplers (both Johannes and the Space Telescope) we can start to look for alien worlds that have temperatures similar to the ones we find here.  The hope is that one day we will find evidence of life on another planet.  And then we can begin our transition into any one of several sci-fi galactic civilizations (my personal favourite is Foundation, but some people prefer Star Wars, Star Trek, or Eve Online).

Unfortunately, in May 2013 one of the components that kept Kepler (the telescope) stable failed, meaning the mission was apparently over.  The mission had been hugely successful, discovering over 1000 confirmed planets, with 4000 other planet candidates waiting to be confirmed.  It turns out that most stars probably have planets and that a lot of planets in the galaxy might be the right temperature to be habitable.

Astronomers are nothing if not persistent though, so an ingenious method was devised to make sure Kepler can continue observing even without its stabilizer.  This new mission, dubbed K2, uses the radiation pressure from the sun itself to balance the telescope.  Instead of continuously observing the same 145 000 stars, K2s targets will change periodically as it orbits the sun.  There will be far less data coming down, but as of this writing four new planets have already been found since K2 began in earnest in June 2014.

There's a lot of information there, but I think the most impressive bit is that K2 is metaphorically balancing a pencil on a fingertip, remotely, from 150 million km away.  Image by NASA
There’s a lot of information there, but I think the most impressive bit is that K2 is metaphorically balancing a pencil on a fingertip, remotely, from 150 million km away. Image by NASA

Currently, while there are all sorts of really interesting exoplanets out there (from hot jupiters like 51 peg b to mirror earths like Kepler-438b), we have yet to find signs of life.  But I think that before too long, we will.  Just as the truth of heliocentrism eventually came out thanks to Kepler, a telescope with his name will be instrumental in uncovering the truth of life elsewhere in the universe.  Just like he said,

“Truth is the daughter of time, and I¬†feel no shame in being her midwife” Johannes Kepler