Iron–sulfur World Theory - Origin of Life - Pioneer Organism

Pioneer Organism

Wächtershäuser proposes that the earliest form of life, termed "pioneer organism", originated in a volcanic hydrothermal flow at high pressure and high (100 °C) temperature. It had a composite structure of a mineral base with catalytic transition metal centers (predominantly iron and nickel, but also perhaps cobalt, manganese, tungsten and zinc). The catalytic centers catalyzed autotrophic carbon fixation pathways generating small molecule (non-polymer) organic compounds from inorganic gases (e.g. carbon monoxide, carbon dioxide, hydrogen cyanide and hydrogen sulfide). These organic compounds were retained on or in the mineral base as organic ligands of the transition metal centers with a flow retention time in correspondence with their mineral bonding strength thereby defining an autocatalytic "surface metabolism". The catalytic transition metal centers became autocatalytic by being accelerated by their organic products turned ligands. The carbon fixation metabolism became autocatalytic by forming a metabolic cycle in the form of a primitive sulfur-dependent version of the reductive citric acid cycle. Accelerated catalysts expanded the metabolism and new metabolic products further accelerated the catalysts. The idea is that once such a primitive autocatalytic metabolism was established, its intrinsically synthetic chemistry began to produce ever more complex organic compounds, ever more complex pathways and ever more complex catalytic centers.

The fundamental idea of the origin of life according to the iron–sulfur world theory can be simplified in the following brief characterization: Pressurize and heat a water flow with dissolved volcanic gases (e.g. carbon monoxide, ammonia and hydrogen sulfide) to 100 °C. Pass the flow over catalytic transition metal solids (e.g. iron sulfide and nickel sulfide). Wait and locate the formation of catalytic metallo-peptides. Some crucial aspects of this theory have been confirmed experimentally.

Read more about this topic:  Iron–sulfur World Theory, Origin of Life

Other articles related to "pioneer organism":

Pioneer Organism

A pioneer organism is an organism that populates a region after a natural disaster or any other event that may have caused most life in that area to disappear. Common pioneer organisms include lichens and algae. Mosses usually follow lichens in colonization, but cannot serve as pioneer organisms. Pioneer organisms modify their environment and establish conditions under which more advanced organisms can live. In some circumstances, other organisms can be considered pioneer organisms. Birds are usually the first to inhabit newly created islands, and seeds, such as the coconut, may also be the first arrivals on barren soil.

See also: Ecological succession, Primary succession, and Secondary succession


Famous quotes containing the words organism and/or pioneer:

    Apathy is one of the characteristic responses of any living organism when it is subjected to stimuli too intense or too complicated to cope with. The cure for apathy is comprehension.
    John Dos Passos (1896–1970)

    America is the civilization of people engaged in transforming themselves. In the past, the stars of the performance were the pioneer and the immigrant. Today, it is youth and the Black.
    Harold Rosenberg (1906–1978)