"Primordial Soup" HypothesisFurther information: Miller–Urey experiment
No new notable research or theory on the subject appeared until 1924, when Alexander Oparin reasoned that atmospheric oxygen prevents the synthesis of certain organic compounds that are necessary building blocks for the evolution of life. In his The Origin of Life, Oparin proposed that the "spontaneous generation of life" that had been attacked by Louis Pasteur did in fact occur once, but was now impossible because the conditions found on the early Earth had changed, and preexisting organisms would immediately consume any spontaneously generated organism. Oparin argued that a "primeval soup" of organic molecules could be created in an oxygenless atmosphere through the action of sunlight. These would combine in evermore complex ways until they formed coacervate droplets. These droplets would "grow" by fusion with other droplets, and "reproduce" through fission into daughter droplets, and so have a primitive metabolism in which those factors which promote "cell integrity" survive, and those that do not become extinct. Many modern theories of the origin of life still take Oparin's ideas as a starting point.
Around the same time, J. B. S. Haldane suggested that the Earth's prebiotic oceans—different from their modern counterparts—would have formed a "hot dilute soup" in which organic compounds could have formed. This idea was called biopoiesis or biopoesis, the process of living matter evolving from self-replicating but nonliving molecules.
In 1952, in the Miller–Urey experiment, a mixture of water, hydrogen, methane, and ammonia was cycled through an apparatus that delivered electrical sparks to the mixture. After one week, it was found that about 10% to 15% of the carbon in the system was now in the form of a racemic mixture of organic compounds, including amino acids, which are the building blocks of proteins.
The underlying hypothesis held by Oparin and Haldane was that conditions on the primeval Earth favored chemical reactions that synthesized organic compounds from inorganic precursors. A recent reanalysis of the saved vials containing the original extracts that resulted from the Miller and Urey experiments, using current and more advanced analytical equipment and technology, has uncovered more biochemicals than originally discovered in the 1950s. One of the more important findings was 23 amino acids, far more than the five originally discovered.
Famous quotes containing the words hypothesis, primordial and/or soup:
“The wheels and springs of man are all set to the hypothesis of the permanence of nature. We are not built like a ship to be tossed, but like a house to stand.”
—Ralph Waldo Emerson (18031882)
“Like Freud, Jung believes that the human mind contains archaic remnants, residues of the long history and evolution of mankind. In the unconscious, primordial universally human images lie dormant. Those primordial images are the most ancient, universal and deep thoughts of mankind. Since they embody feelings as much as thought, they are properly thought feelings. Where Freud postulates a mass psyche, Jung postulates a collective psyche.”
—Patrick Mullahy (b. 1912)
“In contrast to the flux and muddle of life, art is clarity and enduring presence. In the stream of life, few things are perceived clearly because few things stay put. Every mood or emotion is mixed or diluted by contrary and extraneous elements. The clarity of artthe precise evocation of mood in the novel, or of summer twilight in a paintingis like waking to a bright landscape after a long fitful slumber, or the fragrance of chicken soup after a week of head cold.”
—Yi-Fu Tuan (b. 1930)