See, in its early days, life wasn't all that interesting. There were only two types of organisms floating around, bacteria and archaea — small, single-celled creatures with only the most primitive internal infrastructure. These cells didn't have the organelles required for complexity, like mitochondria (which produce energy) and nuclei (where DNA is stored and transcribed).
"We Always Knew Our Ancestors Were Microbes. Now We Found Them." is from the January 12, 2017 Speaking of Science section of The Washington Post. It was written by Sarah Kaplan and narrated by Jill Melancon.