History of Life

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History of Life

• Chapter 14.2Earths History

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The Formation of Earth

• Age of Earthmore than 4 billion years
• Determined by examining layers of rock
• Radiometric Datingdetermines age by comparing
  the percentages of a radioactive isotope and a
  stable isotope
• Half Lifeamount of time for one half of any
  sample size to decay to a stable form

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First Organic Compounds

• Oparin Haldane
• Hypothesis at high temperatures, the gases in
  the earth's early atmosphere would form organic
  compounds (such as amino acids)
• Never tested the hypothesis

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First Organic Compounds cont.

• Miller Urey
• Tested Oparins hypothesis
• Succeeded in producing organic compounds
• Other scientists have produced ATP nucleotides
  (similar exp. set up)
• Other scientists hypothesize organic compound
  were carried by debris from space

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From molecules to cell-like structures

• Foxresearched structures that may have given
  rise to first cells
• Microspheres made of proteins organized as a
  membrane
• Coacervates droplets made of molecules of
  different types (lipids, amino acids, sugars)
• Both will form spontaneously, no genetic material

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