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Inevitable Life? Eric Smith 18 April 2007 • Why is there life on earth at all? • How and where did it originate? • Why has life persisted? • Does the biosphere contain relics of emergence? Accidents can matter “Any replay of the tape would lead evolution down a pathway radically different from the road actually taken.” Against vitalism and animism “The biosphere does not contain a predictable class of objects or of events but constitutes a particular occurrence, compatible indeed with first principles, but not deducible from those principles and essentially unpredictable” A “happy accident” “the origin of life appears at the moment to be almost a miracle, so many are the conditions which would have had to have been satisfied to get it going” • What were they thinking? • Is this science or an odd prejudice? • Is a different story truer to life? The (family) tree of life 9OUAREHERE Control and inheritance What (all) is life? NH2 OH O O OH HO O O O O OH HO NH O OH O Bridging chance and necessity O O OH HO NH O OH O O OH HO O O .ECESSITY #HANCE Universal Steady Predictable Variable Fluctuating Contingent The metabolic organization of life 2EDUCTIVE METABOLISMS !UTOTROPHS (ETEROTROPHS /XIDATIVE METABOLISMS Ecologies are more fundamental than individuals 2EDUCTIVE ECOLOGIES /XIDATIVE ECOLOGIES The major transitions in evolution were chemical #OMPLEX#ELLS -ULTICELLULARITY %NERGY#APTURE #ORE-ETABOLISM /XIDATIVE 2EDUCTIVE -3.8 -3.5 -2.0 -0.5 Origin(?) Photosynthesis (?) Endosymbiosis Cambrian explosion The universal core of biochemistry Fatty acids O OH HO O HO HO OH HO OH OH HO O O O OH O O O O OH O O OH HO OH O O O Amino acids OH O O OH OH Sugars O O O O OH O O OH HO OH HO O O O OH HO O Nucleic acids Cofactors O OH OH HO O • Why life? Under stress, Things break down Lightning is the atmosphere breaking down electrically Hurricanes are atmosphere breaking down thermally • The emergence of life: a chemical breakdown? • Where? • What was the stress? The “Heaven” theory of origin The “Hell” theory: Hydrothermal vents White smoker chimney Black smoker The problem solved by life A free lunch you are paid to eat 50 formate $fGo / Carbon 0 oxaloacetate fumarate malate cis-aconitate isocitrate citrate -50 pyruvate A-ketoglutarate succinate methanol acetate -100 ethanol propanol butanol pentanol -150 -200 methane 1 1.5 2 2.5 H2 / CO2 (formation) 3 3.5 4 A chemical Hurricane O OH OH HO OH O HO O O O OH HO O O OH HO O O OH HO OH O O O OH O O O O HO OH HO OH O O O OH O O OH OH OH HO O O O OH O O OH HO O OH HO O Take-home thoughts • Metabolism first! • Life arose and persists to enable metabolism • Emergence of life a chemical breakdown • Biosphere is part of the geosphere