If you think biologists have a pretty good idea about what lives on the Earth, think again.
Scientists say they have just now discovered an entirely new branch on the tree of life. It's made up of mysterious microscopic organisms.
They're related to fungus, but they so different you could argue that they deserve their very own kingdom, alongside plants and animals.
http://www.npr.org/2011/05/12/136207874/a-new-somewhat-moldy-branch-on-the-tree-of-life
