In 1903, physicist Svante Arrhenius hypothesized that the first microscopic forms of life, driven by the radiation pressure of stars, could have arrived on Earth from space in the panspermia hypothesis. The scientific literature of the early 20th century, however, contained speculations on the origin of life. In 1913, Walther Löb synthesized amino acids by exposing formamide to silent electric discharge, so scientists were beginning to produce the building blocks of life from simpler molecules, but these were not intended to simulate any prebiotic scheme or even considered relevant to origin of life questions. Several other early seminal works in the field of organic synthesis followed, including Alexander Butlerov's synthesis of sugars from formaldehyde and Adolph Strecker's synthesis of the amino acid alanine from acetaldehyde, ammonia, and hydrogen cyanide. While Darwin never publicly wrote about the first organism in his theory of evolution, in a letter to Joseph Dalton Hooker, he speculated:īut if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etcetera present, that a protein compound was chemically formed, ready to undergo still more complex changes ” Portrait photograph of Alexander OparinĪt this point, it was known that organic molecules could be formed from inorganic starting materials, as Friedrich Wöhler had described Wöhler synthesis of urea from ammonium cyanate in 1828.

Charles Darwin published On the Origin of Species that same year, describing the mechanism of biological evolution. However, several experiments in the 19th century - particularly Louis Pasteur's swan neck flask experiment in 1859 - disproved the theory that life arose from decaying matter. Until the 19th century, there was considerable acceptance of the theory of spontaneous generation, the idea that 'lower' animals, such as insects or rodents, arose from decaying matter. See also: History of research into the origin of life History Foundations of organic synthesis and the origin of life Moreover, researchers have shown that transient, hydrogen-rich atmospheres - conducive to Miller-Urey synthesis - would have occurred after large asteroid impacts on early Earth. While evidence suggests that Earth's prebiotic atmosphere might have typically had a composition different from the gas used in the Miller experiment, prebiotic experiments continue to produce racemic mixtures of simple-to-complex organic compounds, including amino acids, under varying conditions. Īfter Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that more amino acids were produced in the original experiment than Miller was able to report with paper chromatography. Haldane's hypothesis that the conditions on the primitive Earth favored chemical reactions that synthesized complex organic compounds from simpler inorganic precursors. At the time, it supported Alexander Oparin's and J. It was performed in 1952 by Stanley Miller, supervised by Nobel laureate Harold Urey at the University of Chicago, and published the following year. It is regarded as a groundbreaking experiment, and the classic experiment investigating the origin of life ( abiogenesis). The experiment used water (H 2O), methane (CH 4), ammonia (NH 3), hydrogen (H 2), and an electric arc (the latter simulating lightning) and resulted in the production of amino acids. It is seen as one of the first successful experiments demonstrating the synthesis of organic compounds from inorganic constituents in an origin of life scenario. The Miller–Urey experiment (or Miller experiment ) was an experiment in chemical synthesis carried out in 1952 that simulated the conditions thought at the time to be present in the atmosphere of the early, prebiotic Earth.

Experiment testing the origin of life The experiment

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