A biome is a distinctive ecosystem well-adapted for a specific geographic region and climate: tundra, taiga, savanna, your mouth. Ecosystems, it turns out, are complex, well-adapted, and crowded even as you get into teeny tiny biomes like your mouth, your stomach, and your butt. Colon! I meant to say colon. Sorry about that.
Anyway, the point here is that until very recently we just never knew what was swimming in your spit. But you’ve got something like 700 species of micro-organisms in your mouth alone. Did you brush your teeth this morning? There are only 375 distinct mammalian species in all of Tanzania, home of the famous Ngorongoro Conservation Area. You’ve got a bigger zoo under your tongue! Furthermore, research by Princeton’s Bonnie Bassler and others reveals complex means of cell-to-cell communication among bacteria. Those bugs aren’t swirling around your molars in writhing chaos. In fact they are present in specific well-regulated symbiotic combinations. They make plans. They dance. They do lunch. They do your lunch, actually. And a good thing too, because you’d be pretty worthless working your way through that egg salad sandwich without a gutful of E. coli to help spin it into you and poo.
I got started thinking about this after reading a post over at The Personal Genome: Your microbiota is SOOOO agnotobiotic. In it, the author Jason Bobe serves up these tasty stats. You have:
- 10 billion bacteria per ml of saliva (with 700 or more species in the oral cavity)
- 100 billion micro-organisms per ml of material in the human colon
- 1 trillion bacteria on the human skin (2 square meters total of human skin)
- 10 trillion human cells in our bodies
- 100 trillion micro-organisms in the human gastrointestinal tract
Think about it this way: you’re never really alone.