Did you know that some microbes use sulfur compounds as a food source, leaving hydrogen sulfide – the rotten-egg smelling gas – behind as a waste product? As well as helping digest food in our guts, these particular bacteria also break our bodies down after burial, returning stored nutrients to the ground.
Idan Ben-Barak's book 'Small Wonders' is aptly subtitled 'how microbes rule our world'. We are used to thinking of microbes as germs that must be exterminated at all costs. But most of them have a function – Earth would be a drastically different place without our single-celled companions. Not only are microbes the world’s best composters, they are also responsible for polluting the atmosphere with oxygen – causing the mass extinction of early microbial life of Earth, while allowing oxygen-dependent life as we know it to evolve.
Ben-Barak also explains how even harmful microbes have a function. Through an evolutionary arms race, disease-causing bugs – including those responsible for plagues - have driven the development of complex immune systems.
Still other microbes blatantly manipulate their environment to suit their lifestyle – much like humans do. For instance, Ben-Barak describes the microbe Wolbachia as the “ultimate radical feminist”. Obliged to spend its whole life inside insects, this bacteria can only be transferred from mother to offspring. To ensure transmission, some strains of Wolbachia turn all males they infect into females – via a hormonally induced sex-change operation.
‘Small Wonders’ is an easy, if somewhat disorganised, read. A tour de force of the weird world of microbes, the book doesn’t build up any arguments, and certainly doesn’t reach any conclusions. This is intentional, and the result is a fascinating collection of largely self-contained chapters – in fact, you can delve in almost anywhere and start reading about another wacky adaptation. In his own words words, “Science is a journey, not a destination. Anyone who presents science primarily as an authoritative, well-organised body of established facts is probably trying to sell you something.”
