RE: How did life start? No creationists please
June 18, 2013 at 7:10 am
(This post was last modified: June 18, 2013 at 7:48 am by Anomalocaris.)
(June 18, 2013 at 1:35 am)Minimalist Wrote: Miller's specimens were found and subjected to modern testing methods in 2007. The results....
http://news.bbc.co.uk/2/hi/science/nature/7675193.stm
Quote:"We found not only did these make more of certain amino acids than in the classic experiment, but they made a greater diversity of amino acids."
Miller, using the old methods, had found five amino acids; Jeffrey Bada and his teams tracked down 22. What is more, the overall chemical yields were often higher than in the first set of experiments - the mixture appeared to be more fertile.
Professor Bada points out that today, almost all volcanic eruptions are accompanied by violent electric storms. The same could have been true on the young Earth.
No one doubts Miller Urey experiment worked well to show amino acids can be effectively manufactured under relatively simple conditions provided there is high concentrations of ammonia, methane and hydrogen. If these are present in quantity, addition of nitrogen and carbon dioxide would make miller Urey experiment go even better. But unfortunately mineralogical evidence shows while the icing of carbon dioxide and nitrogen was there, the cake of ammonia and methane wasn't. The earth's atmosphere was never rich in ammonia or methane, at least after the moon forming impact stripped away earth's original crust and atmosphere 4.56 billion years ago. Repeat experiment using only trace amounts of methane and ammonia, and production of amino acids come nearly to a stop.
Miller Urey experiment shows lightning can make amino acids arise out of organic soup in warm little pond as Darwin called it. Mineralogical evidence suggests the warm little ponds had precious little organic soup.
The only thing going for miller Urey experiment is, while it can't convincingly show how amino acids can be made in early earth environments, it could show how environment conducive to making amino acids can be prevalent elsewhere in the early solar system, where amonia and methane were and still are available in high concentrations.
It doesn't matter, amino acids can be brought to earth on asteroids. Now the question is how amino acids climbed the incredibly steep thermal dynamic ladder to form a self replicating molecule, which is essence of how life, as opposed to life's raw materials arose. Here zapping things with lightning only makes things worse, not better.
(June 18, 2013 at 2:50 am)max-greece Wrote: .
Do you have any source material for the pre-cambrian? Everything I have seen starts from the Cambrian explosion and only makes reference to fractal life forms before that which appear to have simply died out.
ediacaran pre-canbrian multicellular fauna
Evidence of multicellular organism 2.1 billion years ago:
El Albani, Et al (1 July 2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago". Nature 466 (7302): 100–104.
