1How Did Life Begin?4 Billion Ma1. What was Earth’s environment like when life arose?2. How is life defined, and how did it arise from non-life?3. What were the characteristics of the very first cells?HARD QUESTIONSWhat is Life?• Ability to store and transmit information= having a genotype• Ability to express that information= having a phenotype• Ability to evolve= change over time2What came first? Protein DNA RNA RibozymeTetrahymena thermophila genotypephenotypeRNA evolution in a test tubeQβ RNA VirusTest tube evolution of RibozymeTetrahymenaTetrahymena ribozyme generation 1generation 9Monomers of CHON3PanspermiaLife elsewhere in the Universe?Fossil Bacteria?Murchison Meteoritealanine,glycineprolinevalineproteinsStanleyMiller’sApparatus(1953)Glycine,AlanineOparin- Haldane ModelNucleotidesChain 10 bases long10-base nucleotides bind to clay20 bp11 bp(montmorillonite)Assemblage of biological polymersOldest known sedimentary rocksBanded iron formation, Akilia Island,Greenland-- 3.8 billion years oldCarbonaceous apatite crystalAkilia Island, Greenland3.8 billion years oldInclusion in crystal, perhaps produced by livingorganism (ratio 12C to 13 C)4History of ImpactsEarthApex Chert Fossils of Western Australia3.5 billion yrs. Living1.5 billionLivingLivingLiving850 Ma950 MaCyanobacteriaJ. W. SchopfCr adle of Life ( 1999)2.1
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