“…bacteria, archaea, protists and fungi? Collectively, these microbial taxa are the most abundant, widespread and longest-evolving forms of life on the planet. What is their contribution to global biodiversity? When microorganisms are taken into account, recent studies suggest that Earth might be home to a staggering 1 trillion (1012) species. If true, then the grand effort to discover Earth’s biodiversity has only come within a 1,000th of 1 per cent of all species on the planet.”

~ Jay T. Lennon & Kenneth J. Locey | There are more microbial species on Earth than stars in the galaxy