2. Where Does Life Come From?

3. Origins of Life (pre-19 th c.) Abiogenesis Heterogenesis

5. Lao-Tzu

6. Francisco Redi (1668)

7. Lazzaro Spallanzani (1768)

9. Louis Pasteur (1864)

10. “Never again will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment”

11. Darwin

12. A.I. Oparin (& David Haldane)

13. Primordial Soup 4.4 bya Oceans have pH of 5.8 Present: CH 4, NH 3, H 2 O, H 2 S, CO 2, CO Absent: O 2 or O 3 Highly reducing atmosphere leads to synthesis of amino acids

15. Stanley Miller (& Harold Urey) 1953

16. Sidney Fox Origin of Coacervates (protocells)

18. Oxygen Revolution 2.2 bya Caused not only metabolic transition but mass extinction

19. Endosymbiont Hypothesis (Margulis 1981)

20. Sexual Reproduction