When I first saw this fantastic color-enhanced electron micrograph image of this millimeter mite, I didn’t recognize it. At first I thought I was looking at something shown at actual size, and that it might be an experiment in man-made robotics. This thing does not look like an natural animal; it looks like it’s made of fiber optics and plastic fittings shrouded in a canvass pressure suit. So it’s not surprising that the tardigrade (water bear) is the one animal on this planet that is capable of living unprotected in outer space. If we dropped some of them on Mars, (with a modest ration of lichens) they could just go on living there forever with no other provisions necessary. 
According to the Astronomy Picture of the Day archive, the tardigrade can go for decades without food or water! They can survive temperatures from nearly zero KELVIN to well above the boiling point of water, because they can actually dehydrate themselves for storage in stasis. They can survive pressures from near zero (space) to well above that on the ocean floor. They can survive direct exposure to dangerous radiation because they can even repair their own DNA!
That means they evolve awfully slowly. They’re ecdysozoans, and one of the most basal of all bilateral animals. There are roughly 500 species known since their discovery in the 1700s, but they also show up in microfossils dating all the way back to the Cambrian! That’s only one new species every million years and they can survive anything. If evolution were a game, these things win!
This makes me wonder something: if the Mars rover ever found life, how would we be able to tell it wasn’t something like this that “snuck aboard” somehow?
IANAB, but DNA sequencing. Life from Earth is of course related to other life from Earth and the DNA should show that.
I immediately recognized it as a tardigrade because I love tardigrades for all the reasons mentioned by Aron. Also, they are adorable. ^^
I want a poster of that picture now. 🙂
DNA might not be conclusive. It’s possible that life has been transferred between Earth and Mars several times in its history, via meteorites. I suppose even a tardigrade might travel in that way. If there is a Martian biosphere and its chemistry is not utterly alien to ours, it will take a while to disentangle what happened.
Aron: have you read Evolving The Alien (Us title: What Does a Martian Look Like?) by Jack Cohen and Ian Stewart?
I think it is a great book on xenobiology and goes in to some detail on the random chance side of evolution that resulted in humans being configured as we are.
Marcus @1:
This song might be for you.
When we destroy the planet in the coming nuclear Armageddon, tardigrades (and cockroaches, who can eat almost anything and are resistant to radiation) will inherit the earth!
Would be interesting to see what they’d evolve into when all those formerly-occupied niches become available to them.
That picture there looks like a Biotic god!
It’s a joke about the Volus from Mass Effect. Their environmental suits look a little like that.
Given long enough, there might be tardigrades telling stories of mad creatures called Cthu’mans that are so big and powerful they don’t even notice beings as small as they are, and they supposedly transplanted the tardigrades to their home long ago in a creation of strange angles that could float through the ether. It is said to be deadly for any species to get large enough and active enough to wake a Cthu’man that sleeps hidden under great mounds of soft, insulated land.
I really should be working right now instead of writing this.
Ain’t it nice that God “intelligently designed” tardigrades with that ability – but not his beloved humans.
And regrowing limbs – I guess he likes lizards more than human amputees.
Ans he likes almost every animal that produces its own vitamin C more than humans…..and guinea pigs
Well, I see you finally stumbled upon us, Mr. Ra. Please allow me to clue you in on what will happen next.
We are just biding our time right now until the moment is right. We expect your self-extinction to take no less than about another 100 years, at which time we will begin constructing our standard-design starships using the nanotechnology biofabricators inside of us which your species has yet to detect (and probably won’t). Thanks to the mineral resources you have so conveniently extracted from this planet’s crust and refined for us to use, we will soon build and launch our next wave of ships to adjacent star systems and repeat the process. This sector of the galaxy is the last one remaining for us to colonize. Once this task is complete, a galaxy-wide long-range correlation will commence (similar to what your species observes in and calls a dissipative system) and the next phase of our life cycle will begin. The millimeter-sized organisms that you now see will spontaneously and rapidly transform and grow into life-forms approximating your own size but will look like… well, I won’t bother you with the details, right now, Mr. Ra. Your species won’t be around to witness the event, but suffice it to say it would have been the most extraordinary thing your kind would have ever beheld.
What happens after this? We really do not know. We have seen this transformation take place in most of the galaxies in this region of the Universe, and many of our scientists believe that a similar long-range spontaneous metamorphosis will occur once colonization of this local group of galaxies is complete. We await with great anticipation this next stage of our development, if it occurs at all. For now such a possibility is only mere speculation.
In the meanwhile, our… brothers and sisters, if you will (again, there is no point in getting into details)… anxiously await the completion of our work here. So for now just enjoy your remaining time with us. Study us. Get to know us. Be our friends.
And do please continue to take a few of us up into orbit in your primitive space vehicles from time to time. Yours is the only species we’ve encountered who developed that capability, and that last time you took us aboard and outside your “Space Shuttle” the experience was shared planet-wide amongst us and reminded us of the exciting journey which we are soon to embark on. After we all had a long good giggle, of course.
So please, do get on with it. Burn up the rest of those fossil fuels, raise the temperature of the planet a few degrees more, we don’t mind. It’s no chitin off our noses.
We anxiously await your self-extinction.
aw. May I please burst yer bubble with the inconvenient facts?
They only survive all those crazy stressors by nearly completely dehydrating (anhydrobiosis). This state of ‘suspended animation’ is called a ‘tun’ (an excellent Scrabble word when really stuck). If you dropped them on Mars they’d just stay that way; they do require water and oxygen to move, eat, reproduce, live.
?
nah. Obviously they have to post-date the deuterostome/protostome and ecdysozoan/lophotrochozoan splits.