This article was originally featured on Knowable Magazine. More than 1.5 billion years ago, a momentous thing happened: Two small, primitive cells became one. Perhaps more than any event—barring the ...

Ciliates, a group of single-celled ciliated eukaryotes, have been studied since the dawn of light microscopy, with over 10,000 species described. Cilia are the key feature of ciliates and contribute ...