Pretty much all the life you can see without the help of a microscope–toadstools, poplars, shortstops–is multicellular. Life began as single-celled microbes over 3.5 billion years ago. But at least 25 times over the course of the history of this planet, microbes have come together to form multicellular collectives–otherwise known as bodies.

These transitions are particularly intriguing to evolutionary biologists, because the nature of evolution itself changed along the way. If you’re a microbe, natural selection favors mutations that affect your nature as a single cell. If you stumble across a way to feed on a new nutrient, your descendants may grow faster than the competition and come to dominate your population. Single-celled microbes can evolve to be altruistic–even to commit suicide for the good of their fellow microbe–but they only do so to help their single-celled relatives.

Continue reading “Watching Bodies Evolve” →

Earlier this week, the Centers for Disease Control warned that we’re facing an onslaught of “nightmare bacteria”–a group of highly resistant, highly deadly microbes. Talk of the Nation, the National Public Radio Show, asked me to join them to talk about these bugs yesterday. You can listen to it here:

This is the sort of story that seems tailor-made for confusion, thanks to the squirrelly nature of microbiology. As my fellow guest on the show, NPR science correspondent Rob Stein, observed, we are not dealing with an out-of-control plague that will wipe out the planet. On the other hand, as I pointed out, these nightmare bacteria are killing people, and will probably kill more people in the future. I’m sure that listeners were left scratching their heads a bit. So I wanted to take a moment this snowy morning to explain the news at more length.

Continue reading “The “Nightmare Bacteria”: An Explainer” →