Monday, June 25, 2012
Primordial Soup (part 4)
See, scientists had a big problem when it comes to investigating the origins of life on the primordial Earth. And they are not as accepting of Miller’s experiment do to many problems associated with the atmosphere of Earth. The problem is our life supporting oxygen. See, an atmosphere with oxygen equaled no amino acids and thus so critters. This is because amino acids and sugars will react with oxygen to form good old carbon dioxide (CO2). But, on the other hand, an atmosphere without oxygen equaled no ozone, and yet again, no life, since without an ozone layer (O3), ultraviolet rays would soon break down organic life (Origin). So scientists have to come up with a way to allow for the formation of amino acids in an environment that will all for its formation and protect it from radiation. Some scientists are skeptics of it because they do not believe that many of the condition were accurate with that of early Earth. For one, while it is believed that lightning storms were very common, they did not occur in a continuous supply of energy that Miller used in his experiment to form amino acids and other organic compounds (Miller/Urey). It is now believed that the early earth's atmosphere did not contain predominantly reductant molecules either. In the 1980’s, “scientists agreed that nitrogen and carbon dioxide” would have been present in high qualities because “Earth was very hot at those times and composed of nickel and iron” (Four). One of the most criticized aspects of the Miller- Urey experiment was the fact that is was conducted in a closed system not exposed to the primordial atmosphere which would most likely have destroyed that which was vital for life. Another argument was the fact that the amino acids that were found on Earth could also be found in outer space. In 1969, “a meteorite recovered in Australia, was shown to be rich in amino acids.” About 90 different amino acids were identified and nineteen of the amino acids could also be found on the Earth (Miller/Urey). So in theory, our amino acids could have stolen a ride to Earth via a meteorite. Or, since amino acids were proven to survive in the unfriendly depths of space, it also raised the question; could the amino acids have formed and survived while the Earth was undergoing its planet developing stage?And thus we come across the problems that Miller is facing with his experiment.
Posted by annajazz at 6/25/2012 10:12:00 PM