You're 90% Microbe
Bacteria and Archaea look identical under a microscope, but they're as genetically different from each other as either is from humans. Bacteriophages — viruses that infect bacteria — are the most abundant biological entities on Earth: ten million trillion trillion of them.
Viruses can't reproduce alone, have no metabolism, and arguably aren't alive — yet they've shaped the evolution of every organism on Earth. Protists are the grab-bag kingdom: amoebas, paramecia, and malaria-causing Plasmodium, some closer to animals than to each other. Prions aren't even organisms — just misfolded proteins that make other proteins misfold. No DNA, no RNA, but transmissible and deadly.
140 microbes spanning life's deepest divisions. From the bacteria fermenting your yogurt to archaea thriving in volcanic vents.
Did you know?
- *Archaea and bacteria look similar under a microscope but are as genetically different from each other as either is from humans.
- *Bacteriophages — viruses that infect bacteria — are estimated to be the most abundant biological entities on Earth, numbering around ten million trillion trillion.
- *Prions contain no DNA or RNA at all; they are simply misfolded proteins that can convert normal proteins into copies of themselves.
- *Your body contains roughly as many bacterial cells as human cells — the old claim of a 10-to-1 ratio has been revised to approximately 1-to-1.
- *Tardigrades (water bears) can survive in the vacuum of space, but the microbes in your gut outnumber the total human population by a factor of trillions.
What is GuessKin?
GuessKin is a free daily guessing game built on real-world taxonomy. Choose from over 20 categories and try to identify the mystery microbe. Each guess reveals how closely related your answer is to the target through a shared classification tree.
How does it work?
Every microbe in GuessKin sits on a taxonomy tree — a branching hierarchy that shows how things are classified and related. When you make a guess, the game shows you the nearest common ancestor between your guess and the answer. The closer that ancestor is to the answer, the warmer you are. The tree visualization grows with each guess, narrowing down where the answer lives and helping you triangulate.
How to get the best score
- •Fewer guesses is better. The ideal game is guessing it in 1. Every guess counts against your score.
- •Speed matters too. The timer starts on your first guess. Quick, confident answers are rewarded.
- •Read the tree. Each guess gives you real taxonomic information. Pay attention to which branch the answer is on and which branches you've already ruled out.
- •Start broad, then narrow. Your first guess splits the tree. Pick something that gives you maximum information, then drill into the revealed branch.
Each GuessKin category uses a real classification system. These aren't made-up groupings — they're the same systems scientists and specialists actually use. New categories are added regularly. Every category is free, with no accounts and no ads.