1. organisms develop between 4 billion (when the crust solidified) and 3.5 billion (when bacteria made stromatolites) years ago.
2. an ancient atmosphere has little free oxygen, much lightning, volcanism, ultra-violet (UV) radiation, and meteorite bombardment.
3. the organisms that developed were products of chemical evolution.
   1. abiotic synthesis and organic monomer accumulatoin.
   2. monomers form polymers and molecules.
   3. these macromolecules aggregate into droplets called protobionts with different chemical traits than their environment.
   4. heredity and genetics evolves from proteins to nucleic acids (Note:  this step may have occurred prior to step three).

Testing the Origin of Life

1. in the 1920s, AI Oparin from Russia and JBS Haldane from Great Britain independently hypothesized abiotic synthesis and reasoned why it cannot happen in this day
   1. because the oxidized atmosphere is not conducive to spontaneous synthesis.
   2. because oxygen attacks chemical bonds, taking their electrons.
2. in 1953, Stanley Miller and Harold Urey tested Oparin and Haldane's hypothesis:
   1. they recreated that atmosphere:  water vapor, hydrogen, methane, ammonia.
   2. however this atmosphere was more reduced because billions of years ago volcanoes emitted enormous amounts of carbon monoxide, carbon dioxide, and nitrogen.  despite this the most important characteristic was the lack of oxygen
   3. the end result:  Miller and Urey artificially synthesized random amino acids with those 4 major ingredients.

Next:  "Polymerization."