The Origins of Life and Precambrian Evolution. Chapter 16. Questions. What was the first living thing? Where did it come from? What was the last common ancestor of today’s organisms and when did it live? What is the shape of the tree of life?
Red boxes represent lunar impacts; blue boxes terrestrial impacts (some of which are hypothetical.
Dashed line represents impact energy sufficient to vaporize the global ocean.
A = Archaean spherule beds; V = Vredevort; S = Sudbury; M = Manicougan; K/T = Cretaceous-Tertiary impact crater (Yucatan)