the planet's toughest creatures

October 6, 2008

In early September, a small batch of tiny invertebrates called tardigrades (or water bears) was launched into space without any protection. The tiny creatures survived, came back safely and continued to breed normally, with no notable radiation damage. So what’s their secret? Theyre anhydrobiotic organisms, living things that evolved to survive extreme droughts by entering a state of suspended animation and repairing their DNA when its damaged by a lack of water.

water bear

Deep inside their cells are pristine DNA fragments that can be used to replace or fix a damaged section of its genome through a process known as annealing. (read a very detailed explanation of how it works) This ability is so unique, its been proposed that anhydrobiotic creatures came from outer space and are proof of panspermia. Its an even more tempting proposition when we consider the fact that we are too complex and too big to have such an ability. The extreme conditions that require extreme adaptations aren’t conductive to complex, macro-organisms. Theyd die before they would be able to develop enough structure and complexity.

So could a colony of alien creatures related to water bears and super-tough bacteria evolve on another world, get blasted into space by an explosion, survive the millions of years it takes to travel to another planet and help spark life on this one? How about putting this idea to the test by blasting water bears to Mars and checking up on them with one of the rover missions there? How expensive could it be to blast a piece of rock to Mars and how much could we learn?

[ micrograph courtesy of Goldman Labs ]

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  • I’m not sure Panspermia talks about anything larger than a bacteria as a possible seed for life, but this water bear sure looks like a much cooler ancestor than a germ. You have my vote.

  • Jypson

    I wonder how these water bears are treated by evolution. It seems to have such a firm grasp on its own DNA, that any mutation in its lifetime would be quickly fixed. It would be interesting to see if such an organism could be tracked by its evolving genetic makeup. Each generation would a have a perfect copy of its own DNA without any altercations. This is going to keep me up thinking tonight, great.

  • Nicholas Wolff

    The theory about these creatures being ancestors from an alien species could be true, but you would have to think about the arrival of these creatures. Because of their survivability, scientists have found these creatures everywhere from the darkests depths of the ocean to the highest peaks of the Himalayas. They are found in all countries, all continents and that would be quite a feat for a creature so small. For this to happen, I would imagine there having to be trillions of these floating through space for millions of years. Maybe some cataclysmic event happened on some other planet and shot them through the universe. I would imagine some wouldn’t have survived the trek, some may have wandered to close to a star or hit by a meteor. Even with so many landing on earth, it would take quite some time after that for them to be able to spread to all of the continents. Unless of course they landed on Pangea. :)