The paper linked above offers a wonderfully humbling correction to our instinctive sense of humanity’s importance. By biomass, all 8 billion humans together are little more than a biological rounding error: viruses outweigh us by roughly three to one, while bacteria outweigh us by more than a thousand to one. If Earth ever convened a Parliament of All Living Things, the bacterial delegation would not merely hold a majority it would possess something close to absolute legislative power, effortlessly passing whatever laws served bacterial interests. Humanity would occupy a few almost invisible seats at the back of the chamber. This would work, of course, only if plants the true biomass superpower of the planet were conveniently disqualified under a rather self-serving “locomotion rule.”
P.S. There is another curious implication of thinking about life on this scale. If one considers the immense quantity of bodily fluids contained in all the animals that have ever lived the roughly 100 billion humans who have existed alone account for billions of tonnes then an extraordinary amount of Earth’s water has, at one time or another, passed through living bodies. In that sense, some of the water we drink today may once have been part of an animal that lived centuries, millennia or even millions of years ago.
