Resistance redux

The human species is one of the youngest forms of life on earth, yet it has become the dominant force in evolution. Most of the main environmental problems—global warming, pollution, loss of biodiversity, land erosion and the emission of greenhouse gases—are caused, either directly or indirectly, by human activities. Optimists hope that these huge environmental changes might be at least partly reversible, if humans agree to take massive and concerted corrective action sooner rather than later. Pessimists—or perhaps realists—hold that it might already be too late, and that we are markedly changing the physical and biological environment with as yet unclear repercussions for humanity.In any case, even if humans are the dominant species on our planet, they are not the most important from a purely biological point of view. The omnipresent microbial population is not only the oldest form of life on Earth, having emerged more than 3 billion years ago, but also the most numerous and biologically diverse, and the most able to adapt to environmental changes. According to many pundits, microbes will be the sole survivors of any global catastrophe short of the complete destruction of all life on Earth.Humans are essentially interlopers in a microbial world. Our evolution has been completely dependent on microbes; this holds true for all of the commensal bacteria that make up the human microbiome, as well as the microorganisms in the external environment. In fact, all living organisms rely on the presence and activity of microbes for their survival, just as viruses and bacteria rely on favourable hosts and environments for growth and reproduction. From the point of view of a microbe, the human body is just one such host that can supply its guests with the proverbial ‘free lunch’.> According to many pundits, microbes will be the sole survivors …