You Are an Ecosystem

Humans did not evolve as standalone organisms. You evolved as a superorganism — a walking habitat for trillions of microbial partners whose genes outnumber your own by a wide margin. Every surface of your body hosts specialized communities adapted to that exact environment.

Mice raised entirely without bacteria develop shrunken immune systems and abnormal brain chemistry. Your microbiome produces vitamins, trains immune cells, and manufactures neurotransmitters your own DNA cannot encode.