RE: How did the chemicals for life come together??..
November 4, 2010 at 3:55 am
(This post was last modified: November 4, 2010 at 11:02 am by Anomalocaris.)
Minor correction, the sun was 30% less luminous 4 billion years ago, not 30% as luminous.
Also since the 60 year old Miller-Urey experiment we have refined our understanding of the hydrological and geological conditions on primordial earth, and have discovered not only additional ways to create amino acids, but the entire process of creation up to up to RNA - one step short of DNA - encapsulated in organic membranes similar to cell membrane, forming a cell like packages, in the condition of a type of hydrothermal vent that still exists on earth now, and was more abundant in the more vigorous plate tectonics of a younger earth with a radioactively hotter core. We've proceeded considerable distance down the path to actually demonstrating the entire abiogenesis process up to the creation of an live cell. Furthermore, this process occurred in deep sea, is powered by geothermal energy, and uses raw material supplied entirely by hot water leaching material out of rocks through which it percolated. Thus the process of abiogenesis is indifferent to any effects of reduced solar output and would have happened on the primitive earth even if there were no sun at all. Sheltered by the sea and deriving both energy and material from the interior of the earth, the very first living cell was also completely independent of the composition of the atmosphere, so long as there was some atmosphere to keep the ocean from evaporating into space. The atmosphere could consist of krypton gas or sulfuric acid vapor for all the first organism cared. It was only later that life evolved to take advantage of both the sun and the atmosphere.
See Baaske P , Weinert FM , Duhr S , Lemke KH , Russell MJ , Braun D (2007) Proceedings of the National Academy of Science, USA 104:9346–9351
Not only can abiogenesis happen, and did happen, it may have happen more than once in the history of life on earth. It was once thought that all life on earth descent from a common, bacteria like Prokaryote ancestor. It is now recognized that what was once thought to be the one big related family of bacteria in fact consist of two different families- the archaea, and the prokaryote. Members of these two families look similar under microscope, but uses completely different biochemical processes for the most basic functions in such a way that cast doubt about whether the two families could have descended from one common functioning organism. Thus abiogenesis may have happened on earth at least twice.
see Woese C, Fox G (1977) Proceedings of the National Academy of Science, USA, 11:5088-90, Gribaldo S, Brochet-Armenet C (2006) Philosophical transactions of the Royal Society, Biological Sciences, 361 (1470) 1007-22
Thus the majority opinion of the life sciences community, far from questioning in principle the concept of abiogenesis, has found that abiogenesis is far more versatile and adoptable process then was ever imagined by Miller and Urey. Instead of requiring a plausible, but narrow range of atmospheric and hydrological conditions, abiogenesis is now thought to be possible in virtually any substantial body with an initial inventory of organics, conditions for bodies of liquid water ito exist a large variety of solution, pressure and temperature conditions, and an active hydrothermal system. Abiogenesis very likely will happen if it could happen, and it could happen in a whole lot more environments then we thought just 15 years ago.
Also since the 60 year old Miller-Urey experiment we have refined our understanding of the hydrological and geological conditions on primordial earth, and have discovered not only additional ways to create amino acids, but the entire process of creation up to up to RNA - one step short of DNA - encapsulated in organic membranes similar to cell membrane, forming a cell like packages, in the condition of a type of hydrothermal vent that still exists on earth now, and was more abundant in the more vigorous plate tectonics of a younger earth with a radioactively hotter core. We've proceeded considerable distance down the path to actually demonstrating the entire abiogenesis process up to the creation of an live cell. Furthermore, this process occurred in deep sea, is powered by geothermal energy, and uses raw material supplied entirely by hot water leaching material out of rocks through which it percolated. Thus the process of abiogenesis is indifferent to any effects of reduced solar output and would have happened on the primitive earth even if there were no sun at all. Sheltered by the sea and deriving both energy and material from the interior of the earth, the very first living cell was also completely independent of the composition of the atmosphere, so long as there was some atmosphere to keep the ocean from evaporating into space. The atmosphere could consist of krypton gas or sulfuric acid vapor for all the first organism cared. It was only later that life evolved to take advantage of both the sun and the atmosphere.
See Baaske P , Weinert FM , Duhr S , Lemke KH , Russell MJ , Braun D (2007) Proceedings of the National Academy of Science, USA 104:9346–9351
Not only can abiogenesis happen, and did happen, it may have happen more than once in the history of life on earth. It was once thought that all life on earth descent from a common, bacteria like Prokaryote ancestor. It is now recognized that what was once thought to be the one big related family of bacteria in fact consist of two different families- the archaea, and the prokaryote. Members of these two families look similar under microscope, but uses completely different biochemical processes for the most basic functions in such a way that cast doubt about whether the two families could have descended from one common functioning organism. Thus abiogenesis may have happened on earth at least twice.
see Woese C, Fox G (1977) Proceedings of the National Academy of Science, USA, 11:5088-90, Gribaldo S, Brochet-Armenet C (2006) Philosophical transactions of the Royal Society, Biological Sciences, 361 (1470) 1007-22
Thus the majority opinion of the life sciences community, far from questioning in principle the concept of abiogenesis, has found that abiogenesis is far more versatile and adoptable process then was ever imagined by Miller and Urey. Instead of requiring a plausible, but narrow range of atmospheric and hydrological conditions, abiogenesis is now thought to be possible in virtually any substantial body with an initial inventory of organics, conditions for bodies of liquid water ito exist a large variety of solution, pressure and temperature conditions, and an active hydrothermal system. Abiogenesis very likely will happen if it could happen, and it could happen in a whole lot more environments then we thought just 15 years ago.
