Where Does Life Come From?
Origins of Life (pre-19 th c.) Abiogenesis Heterogenesis
Lao-Tzu
Francisco Redi (1668)
Lazzaro Spallanzani (1768)
Louis Pasteur (1864)
“Never again will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment”
Darwin
A.I. Oparin (& David Haldane)
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
Stanley Miller (& Harold Urey) 1953
Sidney Fox Origin of Coacervates (protocells)
Oxygen Revolution 2.2 bya Caused not only metabolic transition but mass extinction
Endosymbiont Hypothesis (Margulis 1981)
Sexual Reproduction