Old & Odd: Archaea, Bacteria & Protists - CrashCourse Biology #35

Hank veers away from human anatomy to teach us about the (mostly) single-celled organisms that make up two of the three taxonomic domains of life, and one of the four kingdoms: Archaea, Bacteria, and Protists. They are by far the most abundant organisms on Earth, and are our oldest, oddest relatives. Crash Course World History is now available on DVD! Like Crash Course? Follow Crash Course! References for