Take plant-eating animals that rely on microbes to digest tough carbs that they lack the genetic capacity to break down. From the microbes' perspective, by partnering with animals they've created new worlds to exploit.

We evolved with microbes, and it was just a useful, advantageous thing to do, to co-opt signals and molecules that they were already producing. I think the answer is that there was no other choice. Why have we outsourced these important aspects of our lives? In the book, I talk about how microbes shape the guts of fish and mice and other organisms, and throughout, I was interested in the question of why that should be. The complex dance between microbes and the animals they inhabit comes under close scrutiny in science writer Ed Yong's new book 'I Contain Multitudes: The Microbes Within Us and a Grander View of Life' (Ecco, 2016). Rather, they form a vast, interconnected microbial web called a microbiome that interacts with a host species in highly specialized ways, and may even have played a part in shaping their evolution.

These microorganisms help their hosts extract nutrition from otherwise indigestible foods, regulate immune systems and can even influence behavior.Ĭertain microbes are known for causing infection and disease, but the communities of microbial life you live with aren't hostile invaders - nor are they wandering strangers. And that's a good thing, because you'd have a hard time surviving without them.Īll animals, including humans, are teeming with microscopic life on every surface of their bodies, inside and out.

Right this very minute, trillions of microbes - bacteria, fungi and viruses - are jockeying for space on every inch of your skin and in every crevice of your body.

I contain multitudes yong