Viruses may be primitive—but they do a lot of experiments and adapt fast. Could we learn a thing or two from them? The biosphere is a fancy word for the container that contains all the life on Earth. After 4.5 billion years of evolution, it’s unimaginably complex. So far, a total of 1.3 million species have been identified, out of a basket of between 5.3 million to 1 trillion. This extreme range exists partly because the border between life and non-life is not so clear—and so is the definition of species. Microbes alone can be divided into six major types: bacteria, archaea, fungi, protozoa, algae, and viruses. Most scientists don’t consider viruses a life form. Others disagree. We humans lie at the other end of the evolutionary scale. We’re pretty smart, up to a point. Tools have made us apex predators, but physically we’re not that imposing. As the historian