Origins of Life

The initial formation of primitive living structures (protocells) is thought to require a specific supporting chemical environment

  • Early Earth had a chemically-reducing atmosphere, which when exposed to energy in various forms (heat, electrical discharge, etc.) produced a variety of simple organic compounds (monomers)
  • These compounds accumulated in a molecular ‘soup’, allowing for the formation of more complex compounds (polymers)

There are a number of locations posited as providing suitable conditions for the formation of a concentrated chemical soup, including volcanoes, hydrothermal vents, shorelines and outer space

1.  Volcanoes

  • The gas composition of volcanic eruptions contain high levels of fixed nitrogen and other raw materials which could be used for primitive metabolism
  • Intensive volcanic activity could also generate sufficient thermal energy to catalyse the formation of organic molecules

2.  Hydrothermal Vents

  • Hydrothermal vents are regions of the ocean floor where superheated water is released from the Earth’s crust
  • These vents also release hydrogen-rich fluids to create a chemical gradient and pH viable for organic synthesis

3.  Shorelines

  • Organic life may have evolved at a sea shore or other region where there is an alternation of wet and dry conditions
  • The drying of clay particles could have precipitated catalysing reactions needed for the formation of organic molecules

4.  Extraterrestrial Origins

  • The necessary conditions required for the formation of life may have initially been derived on other planets (e.g. Mars)
  • Comets contain a variety of organic material (~20% of a comet’s tail is comprised of organic matter)
  • Heavy meteorite bombardment approximately 4 billion years ago may have delivered organic material to the Earth
  • The theory that life on Earth was initially seeded in space or on another planet is called panspermia

Possible Origins for Life on Earth