Thursday, March 07, 2013

Breathing in a foreign clime

Ah! A moss piglet!

Yes, as good a portrait as I have seen. A color enhanced electron micrograph of a tardigrade. The Astronomy Picture of the Day (APOD). (Click to enlarge.)

Tardigrades ("slow walkers") are as weird a creature as you are likely to find on the planet. They are about a millimeter long –- about half the size of this letter i without the dot. Four stumpy pairs of legs. Male and female, although not with a terribly romantic sex life. Only 40,000 cells. That's it. Behind that smushed in snout there is a brain, such as it is. Such as it needs to be.

Looks like something invented by Beatrix Potter. Moss piglets, they are called. Or water bears. Undeniably cute in their baggy brown suits. I told a biologist friend once I'd like to see one in the flesh. She showed up later with a bottle containing a few ounces of water, some algae, assorted microscopic organisms, and -- wonder of wonders! -- tardigrades. Bliss! Playing like otters in the eyepiece of my scope. They look remarkably like vertebrates of some sort, but they have no bony skeleton. They are invertebrates, related to insects, but so unique they have a phylum all of their own.

Tardigrades do not interest scientists only because they are cute. They are also among the hardiest of multi-celled animals, maybe the toughest animals of all. Dry them out and they go into a state of suspended animation in which they can live for -- well, no one knows. When some apparently-lifeless, 120-year-old moss from an Italian museum was moistened, tardigrades rose as if from the dead and scampered about.

Maura (if by any chance you see this), it is not the only time you have satisfied my curiosity with a gift of life. I remember mutant fruit flies and slime molds and more. And you lent me too a good biology department dissecting microscope to go exploring. I remember something Darwin wrote in Voyage of the Beagle: "Every traveller must remember the glowing sense of happiness, from the simple consciousness of breathing in a foreign clime, where the civilized man has seldom or never trod." I found my foreign clime on the stage of the microscope.