The origin of photosynthesis

The first cells fed on organic substances in the primordial soup as its concentration gradually diminished. It is likely that the scarcity of energy resources imposed a selection. Some cells acquired the ability to feed on others, while other cells developed the ability to synthesize new organic substances by using energy from oxidation. Even today there still are prokaryotes (cells that don’t have an actual nucleus but a nuclear “equivalent”) that draw energy in this way to live, they are the so called chemosynthetic bacteria. Other cells instead could exploit energy from light to transform water and obtain the hydrogen necessary for photosynthesis (a reaction that can transform simple inorganic substances into organic ones such as carbohydrates thanks to the energy given by light). Living organisms that are able to perform photosynthesis however released simple oxygen which, thanks to its high affinity with organic substances, must have killed most primitive cell forms. Only those cells that could handle the increasing oxygen concentration survived. Subsequently some prokaryotes learned to use free oxygen as an oxidant for energy production. This is how respiration appeared bringing with it the great advantage of being a more efficient energy stocking method than fermentation and guaranteeing survival in the oxygen rich atmosphere.

Special reports

From the Multimedia section

  • life

    Current and primordial atmosphere

    Look

    life

    The present day atmosphere

    Look

    life

    Living cells

    Look
  • life

    Beginnig of life in the oceans

    Look

    life

    Stromatolites

    Look

    earth

    Ammonite fossil

    Look
  • earth

    Fossil fish

    Look

    life

    Palaeontology lab

    Look

    life

    Anchylosaurus

    Look
  • life

    Current and primordial atmosphere

    Look

    life

    The present day atmosphere

    Look
  • life

    Living cells

    Look

    life

    Beginnig of life in the oceans

    Look
  • life

    Stromatolites

    Look

    earth

    Ammonite fossil

    Look
  • life

    Current and primordial atmosphere

    Look
  • life

    The present day atmosphere

    Look
  • life

    Living cells

    Look

Facts

  • Life from space

    According to some scientists life has always existed in the Universe just like the Universe...

    Clonation and Future

    The ability to give life to identical organisms, called clonation...

    A frozen mammoth

    During the Pleistocene (approximately 1.5 million years ago)...

  • Bio-luminescence

    Many sea animals, including a lot of fish and molluscs that live in the dark in the ocean depths...

    Bacteria as detergents

    Enzymes are proteins produced by the cells of all living organisms...

    Down-pouring bacteria

    It sounds incredible, but recent researches have found that bacteria can cause some atmospheric phenomena...

  • Bacteria as Sherlock Holmes

    A drop of blood, a fragment of skin or a hair found on the scene of a crime can supply…

    High-fashion bacteria

    Some bacteria, the Clostridia, were used to make textile fibres...

    Bacteria as miners

    The ability of chemoautotrophic bacteria to take energy from...

  • 13 May 2011

    Life from space

    According to some scientists life has always existed in the Universe just like the Universe...

    Clonation and Future

    The ability to give life to identical organisms, called clonation...

  • 17 May 2011

    A frozen mammoth

    During the Pleistocene (approximately 1.5 million years ago)...

    13 May 2011

    Bio-luminescence

    Many sea animals, including a lot of fish and molluscs that live in the dark in the ocean depths...

  • Bacteria as detergents

    Enzymes are proteins produced by the cells of all living organisms...

    Down-pouring bacteria

    It sounds incredible, but recent researches have found that bacteria can cause some atmospheric phenomena...

  • Life from space

    According to some scientists life has always existed in the Universe just like the Universe...

  • Clonation and Future

    The ability to give life to identical organisms, called clonation...

  • 17 May 2011

    A frozen mammoth

    During the Pleistocene (approximately 1.5 million years ago)...