Evolution of Photosynthetic Pathways
The C4 metabolic pathway is a valuable recent innovation in plants.
Photosynthesis is not quite as simple as adding water to CO2 to produce sugars and oxygen. A complex chemical pathway is involved, facilitated along the way by a range of enzymes and co-enzymes. The enzyme RuBisCO is responsible for "fixing" CO2 – that is, it attaches it to a carbon-based molecule to form a sugar, which can be used by the plant, releasing an oxygen molecule along the way. However, the enzyme is notoriously inefficient, and just as effectively will also fix oxygen instead of CO2 in a process called photorespiration. This is energetically costly as the plant has to use energy to turn the products of photorepsiration back into a form that can react with CO2.
Read more about this topic: Evolutionary History Of Plants
Famous quotes containing the words evolution of, evolution and/or pathways:
“Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.”
—Konrad Lorenz (1903–1989)
“By contrast with history, evolution is an unconscious process. Another, and perhaps a better way of putting it would be to say that evolution is a natural process, history a human one.... Insofar as we treat man as a part of nature—for instance in a biological survey of evolution—we are precisely not treating him as a historical being. As a historically developing being, he is set over against nature, both as a knower and as a doer.”
—Owen Barfield (b. 1898)
“All pathways by His feet are worn,
His strong heart stirs the ever-beating sea;
His crown of thorns is twined with every thorn;
His cross is every tree.”
—Joseph Mary Plunkett (1887–1916)