BIO 123 Lecture Notes - Lecture 5: Hydrogen Sulfide, Radiocarbon Dating, Sedimentary Rock
20 Feb 2017
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Document Summary
Estimated 5 billion species have ever lived on earth. 8-10 billion species currently a live on earth: origin of life and early history of life on earth. Earth formed 4. 6 billion years ago - same with the rest of solar system. Heavy bombardment of earth by meteors likely vaporized water and prevent seas from forming before 4. 2 - 3. 9 billion years ago. Early atmosphere likely contained - water vapor + chemicals released by volcanic eruptions. Nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide. Chemicals contain elements that make cellular molecules: c,n, o, h. Water vapor, chemicals released by volcanic eruptions. Nitrogen , nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide. + energy - lightning, volcanic eruptions, heat, meteorite impacts, high levels of radioactivity. Miller - urey experiment (1953) - water, methane, ammonia, hydrogen in flask + electric sparks (energy) complex organic molecules (amino acids) Organic molecules become available (amino acids, nucleotides, simple sugars, lipids) life appears.
