Primordial Soup Theory

R.J. Yancey Mrs. Touchton 4th Block 4 October 2005

The Primordial Soup Theory How did the first organisms of the earth come to be? There are many theories on how life developed, but none that stand out as much as the Primordial Soup Theory. "Primordial" means happening first in a sequence of time. The Primordial Soup Theory states that about 3.5-3.8 billion years ago the Earth's atmosphere was made up of nitrogen, ammonia, methane, and hyrdrogen. There was either very little or no oxygen in the Earth's atmosphere at this time. Energy from either, the sun, volcanos, or lightning fueled the chemical reactions between these gases. When it would rain, the droplets would carry these molecules to a body of water(pond, lake, or possibly an ocean), forming a primordial soup of amino acids. Amino acids, which are the building blocks of proteins, would later evolve into organisms. The Primordial Soup Theory was first conceived in 1924 by Aleksandr Ivanovich Oparin, a Russian Chemist, and another scientist by the name of J.B.S. Haldane. Both men came up with this theory independently. Even though A.I. Oparin and J.B.S. Haldane sparked the idea of Primordial Soup, all of their research was based on circumstantial data. It wasn't until 29 years later that this theory could be tested by experimentation. In 1953, two American chemists, named Stanley Miller and Harold Urey finally came up with an experiment to test the Primordial Soup Theory. Stanley Miller, a chemist at the University of Chicago, and Harold Urey, a physicist devised an experiment to determine if Oparin's hypothesis was plausible. The Urey-Miller experiment used water, ammonia, nitrogen, and methane. The chemicals were sealed inside an array of glass tubes and flasks connected in a loop, with one flask full of water, and the other containing electrodes. They heated the water, until the water began to evaporate. Then, sparks were fired through the synthetic atmosphere of water vapor to simulate lightning. After that, they cooled the atmosphere so that the water could condense and then trickle down into the flask for a continuous cycle. They let the experiment run continuously for a week; heating and condensing the vapor. After that week, Miller and Urey observed that 10-15% of the carbon in the flasks had become simple organic compounds. Out of that, 2% of the carbon formed amino acids which are the building blocks of life. Within the flasks they discoverd 13 of the 21 amino acids that are used to make proteins in living cells. Although the life forms discovered after the experiment were very simple, it still proved Oparin and Haldane's original hypothesis; that organisms could possibly be produced without life requiring life to produce them in the first place. After the Urey-Miller experiment scientists found other types of energy that could be used to produce amino acids such as ultraviolet light, heat, and lightning. Lightning was most likely the most common type of energy to be used during the process of Primordial Soup. Although some people find faults in the Primordial Soup Theory (see Pros and Cons list), it is one of the most full-proof theories that we have. For example, the Meteorite Theory states that life came from meteorites that impacted the earth long ago. This theory fails to mention why, and how that life came to exist in the first place on that meteor; while the Primordial Soup Theory offers the explanation of the amino acids being used to build proteins that eventually make living cells. The Primordial Soup Theory is the way I believe life began. It just seems to have more hard evidence (Urey-Miller experiment) than most other theories. However, no matter what theory you believe in, no one will ever know which is correct, because no one was there when life began to document it. In addition to that, the evidence that was once in the Earth's crust has deteriorated over time. After all, 3.5 billion years is a very long time. The theory of Primordial Soup is just one of the many explanations that scientists have

devised over the years for how life began through testing and experimentation. Although most theories have been proven possible, they are not necessarily how life began on Earth. Even though some scientists have ridiculed the Primordial Soup theory as obsolete, it is still an important outlook on how life may have began on our planet.