Ch 27 Bacteria - Origin of Life Bacteria CH 27 Universe...

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CH 27 Origin of Life & Bacteria
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Universe formed 15 billion years ago (Big Bang) Galaxies formed from stars, dust and gas Earth formed 4.6 billion years ago
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Suns energy stripped away 1 st atmosphere 2 nd atmosphere formed from volcanic outgassing Primitive atmosphere : CO 2 , water vapor, lesser amts of CO, N 2 , H 2 , HCl, and traces of NH 3 and CH 4 (3.5 bya)
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O 2 came in 1.5 bya Autotrophic Organisms: photosynthesis Another environmental change Result in evolution
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0.5 billion years ago Atmosphere O 2 to 1% current Compare to present: 78% N 2 , 21% O 2 , 0.04% CO 2 , + trace gasses Relatively small, most single cell Start of multicellularity Increase in cell complexity
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Life began~ 3.5 bya Organic molecules (C H O N P S) swimming in shallow seas Stage 1: Abiotic synthesis of organic molecules such as proteins, amino acids and nucleotides
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Stage 2: joining of small molecules (monomers) into large molecules
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Stage 3: origin of self-replicating molecules that eventually made inheritance possible
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Stage 4: packaging these molecules into pre-cells, droplets of molecules with membranes that maintained an internal chemistry
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Thomas Huxley - Search for origin of life Bathybias heckali - primordial ooze Wyville Thompson: HMS Challenger (1872-1876) found it was actually diatomacous ooze reacting with seawater and ethyl alcohol
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Miller & Urey (1953)- mixed water vapor, NH 3 , CH 4 , H 2 + electric spark amino acids and other organic compounds electrodes spark CH 4 NH 3 H 2 water vapor condenser boiling water water containing organic compounds
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Ch 27 Bacteria - Origin of Life Bacteria CH 27 Universe...

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