Sciency Words: Tardigrade

August 4, 2017

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:


Tardigrades, a.k.a. water bears… there’s just something lovable about them. They’re kind of cute for microorganisms (or kind of horrifying, depending on which picture you’re looking at). And they’re absurdly tough. They can survive almost anything. They can even survive in space.

There have been several experiments now where tardigrades were taken to low Earth orbit and exposed to the vacuum of space for prolonged periods of time. Most of them survived the experience. In the absence of food, water, or oxygen, tardigrades can enter a state of suspended animation, and their cells have the ability to repair their D.N.A. if it gets damaged by solar or cosmic radiation.

In fact tardigrades seem to be so well adapted to the hazards of space that it’s sometimes suggested (usually not by serious scientists) that these little guys might come from space.

German pastor and zoologist Johann August Ephraim Goeze is credited with discovering tardigrades in 1773. Goeze called them Kleiner Wasserbär, which is German for “little water bear,” because the way they walk on their eight pudgy, little legs reminded Goeze of the plodding movements of bears.

In 1777, Italian biologist/Catholic priest Lozzaro Spallanzani made further observations of these creatures. Spallanzani called them il Tardigrado, meaning “slow walker,” again because of the slow, plodding manner in which they walk. The English words tardy and tardiness are closely related, etymologically speaking.

Today we’ve retained both tardigrade and water bear as common names for these creatures. Apparently some people also call them moss piglets, which is just adorable. Over a thousand species of tardigrade have been identified, all classified under the phylum Tardigrada.

As for the question about where tardigrades came from—are they native to this planet, or did they immigrate to Earth from someplace else?—I can only say this: if tardigrades do have an extraterrestrial origin, they must have arrived on Earth a very, very long time ago. The oldest known tardigrade fossils date back to over 500 million years ago (meaning they may have been here since the Cambrian explosion).

Sciency Words: Type A Behavior Pattern

July 28, 2017

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:


In my daily life, I’ve been hearing a lot about type A and type B personalities lately. Don’t know why. It just keeps coming up in conversations for some reason, but I’m never sure which one I’m supposed to be. Since these are scientific terms, I figured it was time I did some research.

Turns out that type A and type B were originally cardiology terms. They didn’t come from the field of psychology at all. Back in the 1950’s, some cardiologists noticed that they had two kinds of patients: those who sat calmly in the waiting room and those who fidgeted impatiently.

The fidgeters came to be known as “type A,” and they seemed to be more likely to have coronary disorders than the “type B” non-fidgeters. Soon a study was conducted. The type A behavior pattern (abbreviated T.A.B.P.) was further defined as “[…] an intense, sustained drive for achievement and as being continually involved in competition and deadlines, both at work and in their vocations.”

These were people with a lot of ambition, which isn’t necessarily a bad thing, but they also tended to stress themselves out. They got impatient easily, both with themselves and with others, and were sometimes prone to hostile behavior at work, home, or basically anywhere. With that in mind, the results of the study may not seem like a surprise: a clear corrolation between type A behavior and an elevated risk of high blood pressure and heart disease.

If you’re type A, don’t panic. There were some big problems with that initial study, most notably that it only sampled middle-aged men and failed to account for other key health factors like diet. Subsequent research on both men and women of all ages produced less conclusive results.

And yet debate continued for some time after that, possibly because of some undue influence by the tobacco industry. It seems tobacco companies surreptitiously funded more research on type A behavior then argued, both publically and in court, that personality types pose a greater health risk than cigarettes.

It seems cardiologists started abandoning this whole idea by the 1990’s. Psychologists still seem to use the terms, but sparingly. At this point, I’m not sure if the whole type A vs. type B thing is meaningful anymore, scientifically speaking; and yet a lot of people do seem to identify as one or the other.

So I don’t know. What do you think? Are type A and type B behavior patterns useful ways to describe people, or should we just let these terms go?

P.S.: If I must pick one or the other, I’m going to start telling people I’m type B, because I don’t fidget in waiting rooms.

Space Chimp Lives!

June 27, 2017

Today I’d like to share an amusing photograph from the early days of space exploration. This is Ham the Chimpanzee.

His name comes from the laboratory that trained him for his mission: the Holloman Aerospace Medical Center. That’s important to know because Ham’s training is a key part of his story.

Ham was not just another confused and frightened animal strapped into a rocket and launched into space (though it sounds like he was definitely very frightened during his trip). Ham had a mission. He had a job to do during his flight. And he did it.

Specifically, Ham was trained to push a lever when he saw a flashing blue light. During training, he was rewarded with a banana pellet if he did his job correctly (he was also punished with electric shocks if he did his job incorrectly).

Ham’s success was significant because it proved that even under the physical stresses of space flight, it is possible to respond to visual stimuli and perform basic tasks. A human astronaut would therefore be able to operate the controls of a spacecraft during flight, which was an important thing for NASA to know in the early days of space exploration.

P.S.: I assume human astronauts are still rewarded with banana pellets when they do a good job (and also punished with mild electric shocks when they do their jobs incorrectly).


Ham (Chimpanzee) from Wikipedia.

A Brief History of Animals in Space from NASA.

Ham the Astrochimp: Hero or Victim? from The Guardian.

Sciency Words: Stochastic

June 23, 2017

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:


At first glance, stochastic appears to have a pretty easy definition. Basically, it means random. A stochastic event can be defined, quite simply, as a random event. So why do scientists need this weird term? Why can’t they just say random if they mean random?

I’ve seen this word now in a surprisingly wide range of scientific fields, most recently in relation to the population dynamics of endangered species and then in relation to the magnetic field of Jupiter. The thing is that in actual usage, stochastic and random aren’t quite synonyms. A better definition for stochastic might be “seemingly random.”

The word originates from a Greek word meaning “to aim at” or “to shoot at.” So it’s an archery term, but the Greeks also used it to mean “to guess at.” I like this linguistic metaphor because a guess really is like aiming for the truth; whether or not you hit the mark is another matter.

Anyway, the word seems to have migrated from Greek to German to English, and in its modern scientific sense it refers to something that might be predictable in theory but appears to be random in practice. As an example, you may have heard that the flapping of a butterfly’s wings could set in motion a chain of events ultimately leading to a devastating hurricane.

In theory, these butterfly-initiated hurricanes could be predicted, if only we knew the exact locations and flapping behaviors of every single butterfly on Earth (along with a million and one other factors). But in practice, since we can’t gather all the necessary data, we can only make educated guesses about when and where the next hurricane will hit.

In other words, hurricanes are stochastic events. They seem random, even though they’re not.

What’s the Minimum Viable Population of a Space Colony?

June 21, 2017

Let’s say we’ve found a human-friendly planet orbiting another star, and we’ve decided to go colonize it. How many people should we send? In terms of maintaining a healthy human gene pool, what’s the minimum viable population for a distant, isolated space colony?

If you’re anything like me, you’ve spent many a sleepless night pondering that question.

I sincerely doubt anyone can provide us with a firm, specific number. However, there is a sort of generalized rule of thumb in the field of conservation biology called the 50/500 rule.

Originally proposed in 1980 by geneticist Ian Franklin and biologist Michael Soule, the 50/500 rule tells us:

  • Populations below 50 are under near-term threat of extinction due to inbreeding.
  • Populations below 500 are under long-term threat of extinction because the gene pool is too small to adapt to environmental changes.

Except the 50/500 rule is not a hard scientific law. It’s just a rule of thumb, and it has many, many detractors.

Even Michael Soule, one of the co-creators of the rule, seems to have gotten pretty frustrated by the way people took the rule literally. Here’s an interesting and, I think, revealing article about some endangered parrots. A team of conservationists contacted Soule, asking if they should even bother trying to save these parrots, because there were only 48 left.

There also an argument to be made that the numbers 50 and 500 are too low and that a 100/1000 rule would be more appropriate. And of course, can we really apply this rule to all species equally when some species reproduce more rapidly than others or face different kinds of environmental challenges, etc, etc….

Still, if we’re trying to imagine a colony of humans on some distant world, a colony struggling for short-terma and/or long-term survival, I think the 50/500 rule at least gives us a good place to start.

Sneezing in Space

March 15, 2017

So in case you were wondering: yes, astronauts do sometimes sneeze in their spacesuits. And no, there’s nothing they can do about it when it happens. The sneeze just splatters on the helmet’s faceplate.

I believe I first read about this in one of those Time Magazine specials I reviewed last year (click here or here).

The thing I really want to know is how the force of the sneeze affects the astronaut’s motion, especially when the astronaut is not wearing a helmet. For example, what happens when an astronaut is floating freely aboard the I.S.S. or some other spacecraft and suddenly sneezes?

I’d imagine the force of the sneeze could have some amusing propulsive effects in microgravity.

Sciency Words: Ecotype

December 30, 2016

Sciency Words BIO copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:


Let’s say you discover two groups of antelope. Both groups are the same species, but one group lives on the east side of a mountain range and the other group lives on the west side.

Again, these antelope are all the same species of antelope. But because of a geographic barrier, the two groups rarely if ever intermix or interbreed. As a result, one group has developed thicker wool than the other, or they have slightly different antler shapes, or there’s some other distinctive characteristic that one group has and the other doesn’t.

When you find distinctly different groups within the same species, the groups are called ecotypes. Typically, this sort of differentiation occurs within a species because ecotypes are living in separate ecological habitats.

I first encountered this term in a recent article in Scientific American. As a science terminology enthusiast, I find this to be an interesting kink in the ongoing debate over how to define the word “species”—but the article I read was about something even more interesting than that.

Orca Ecotypes

If we ever learn to communicate with orcas (killer whales), we should tell them about Shakespeare.


Orca ecotypes don’t mix, even though there’s nothing stopping them. They’re genetically compatible. Their territories overlap. They encounter each other in the open ocean all the time, but apparently they don’t like to intermingle due to what Scientific America calls “cultural differences.”

We should be careful about anthropomorphizing animal behaviors. When Scientific American says orcas have “cultural differences,” they mean they have different hunting and feeding practices. And also different clicking/whistling patterns for communication.

Actually, that does sound a little bit like orcas have human-like languages, and maybe even a primitive version of human-like culture. And those linguistic and cultural barriers are enough to keep them apart. We really should tell them about Shakespeare. They’d probably understand a lot of Shakespeare’s themes.

P.S.: You may have missed it, but I was trying to make a West Side Story reference with that thing about antelope.