Your Body's a Wonderland
And it's true, technically. We all know there are bacteria and little microscopic creatures that live on and inside our bodies, but did you know how many there are? I saw a documentary on quorum sensing (a recently discovered phenomena whereby populations of bacteria communicate and organize themselves) and the scientist they spoke to said there are ten bacterial cells for everyone ONE of our own! There's more of THEM in YOU than YOU !
While it's a bit icky to think about, clearly its not a problem, because you're still alive and healthy. It got me wondering, however, about a few questions this leads to.
1) Do we need these creatures? Have we co-evolved with them for so long that we now depend on them? Perhaps we are descended from a being that, if it had not carried a helpful bacteria in its gut, would not have survived. But it did survive, and reproduce, and now we all depend on that bacteria...is it possible we'd not survive without it?
2) What happens if you leave the planet to live in a spaceship? Does your bacterial load keep itself replenished, or do you have to be on Earth to pick up vital new critters? And what if you were born on a spaceship? Could you get this bacteria from other people, or is your health going to suffer?
3) Do all our bacterial buddies have the ability to sustain their populations if we left the planet? What if some of them died, and their job was to keep some of the others in check? Will we be injured by the remaining bugs?
I wrote to a science writer at The Register, an English newspaper, who had answered a question on these bugs recently. His answer just confirmed that yes, these things lived on us and their quantities were vast, but he wasn't asked about their function, or what might happen if (a) something goes wrong, or (b) we leave the planet. He said my questions were very interesting and he's going to publish an answer in the paper when he gets some expert advice on the answers. Should be interesting :)
My own guess is that nothing much will happen. I think the populations are mostly self-sustaining and our body chemistry and immune systems are sophisticated enough to compensate if anything goes out of whack. And there's a whole pharmacy of drugs to help us too, if our un-enhanced systems can't cope. People have lived in space aboard Mir and Alpha for over a year and while they have problems with bone-density and muscle atrophy, I haven't heard of any bacterial/micro-fauna problems.
There have also been people raised in sterile conditions (the so-called Boy in the Bubble) who can live without these bacteria having populated their bodies, so it seems we don't "need" those bacteria - our unadorned "native" body has all it needs to survive and digest food.
Still, these creatures, especially the tiny animals, look really cool (though a bit scary) under microscope. And, just to finish on a cheery thought, when you die, it is THEM who will go to work on consuming your remains.