D3. Life Changes the Planet. “Past, Present, and Possible Future of Humanity and the Biosphere”

D3-1. How is time determined in Earth’s record? D3-2. How is the tree of life studied? D3-3. (Oxygen revolution). Supplement D3-4. (Asteroid bombardment of early Earth). Supplement D3-5. (How is the appearance of fossil organisms reconstructed?).