MadSci Network: Evolution |
Sorry, but I have not heard of any silicon based, as opposed to carbon-based, life forms from deep ocean geothermal vents. You asked about silica, but that is silicon dioxide, and therein is part of the problem with silicon chemistry. A number of people have considered whether silicon-based life is possible, and the answer seems to be perhaps, but not without overcoming some pretty big problems. While the bonding of silicon makes it appear that it could make some interesting molecules, the problem arises in capturing, storing, and metabolizing energy from silicon based molecules. Carbon dioxide is gas, diffusable and soluble in water; silicon dioxide, well, is sand! So how would this life work? I know of no scenario for silicon-based life. The chemotrophic life forms from deep-sea vents have as you mentioned contributed tremedously to our understanding of diversity, although I would stop short of saying these discoveries have revolutionized evolutionary biology. They haven't, but they have contributed to our understanding of how and where life arose. Put very simply, the temperature and chemistry of these deep ocean vents makes certain synthetic reactions energetically easy, syntheses of certain molecules will take place here readily that would require enzymes, thus implying preexisting life, elsewhere. If you are interested in this subject, a book by B. D. Dyer and R. A. Obar, Tracing the history of Eukaryotic cells: the enigmatic smile, provides a very good introduction for a knowledgeable reader.
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