The tree of life maps out the relationships between all living things, and it's in constant flux. ... Eukarya and Archaea," Barnes said — the three primary domains of life.

Archaea, hardy single-celled organisms that form the third domain at the top of the universal tree of life, have survived for billions of years in some of the most extreme environments on Earth ...

Truth is, we don’t know how the Tree of Life will fall, and we don’t know when. It could happen in five years, in 40 years, ...