Primary Broth: What is Theory and Experiments?

The theory of primary broth or primordial soup, seeks to define the origin of life on Earth; It was developed by the Soviet scientist Alexander Oparin. At the same time, in the 1920s the British scientist J. B. S. Haldane was creating a very similar theory, and it was the latter who coined the term"soup"to refer to it.

According to this theory, life on Earth originated in a chemical environment that existed about 3.8 billion years ago. Although it is not possible to prove the veracity of this hypothesis, since the conditions of the Earth of that time are not completely known, experiments have been carried out to identify how possible such an event is. However, the origin of life on Earth remains ambiguous. Many scientists support different theories, although none has been proven in its entirety.

What is the theory?

The theory of primary broth is based entirely on the concept of abiogenesis. Abiogenesis is a process by which, in theory, living organisms can be created as a result of chemical reactions generated by non-living compounds.

In short, it is about the creation of life through chemical reactions. It is an evolutionary concept that defines the origin of life through reactions of inorganic matter.

The theory of primordial soup holds that life was generated in an ocean or a well of water that existed on Earth from 3800 million years ago. At that time, the atmospheric conditions of the planet and its chemical composition were in a much more chaotic state than the current one.

At that time there were no plants or life on the planet. According to the theories of Oparin and Haldane, the Earth had a reductive atmosphere. This means that he had very low amounts of oxygen, or even considered that he had no oxygen at all.

Therefore, the theory of the primordial soup (also known as the Oparin-Haldane Hypothesis) argues that life on the planet was generated by the chemical reaction of carbon, hydrogen, water vapor and ammonia.

Historical background and Darwinian belief

From the time of the Greek philosopher and scientist Aristotle, theorized about the possibility that life on the planet had been originated through a process of abiogenesis. Aristotle himself had a simple theory with respect to this: he compared the emergence of worms in decomposed substances with the spontaneous creation of life.

The concept of Aristotle (which originated in the fourth century BC) ceased to be accepted in the mid-seventeenth century, when an Italian scientist demonstrated that larvae in the garbage are generated only when the flies come in contact with it.

The concept of the Italian, whose name was Francesco Redi, supported in its totality the idea that every living form should be generated from another living form. This concept is what is called biogenesis; the creation of life based on life itself.

Later, we experimented with the origin of microbes in environments that were not exposed to water. When the experiment was failed, the possibility of an emergence through abiogenesis was ruled out.

However, Charles Darwin did theorize about the possibility that life could have originated in a well, when the Earth was in a much more primitive state. He considered that, under a series of determined conditions, it is possible that life is generated by abiogenesis.

Experiments

To test the theory of Oparin and Haldane, two main experiments were carried out that have served as bases to give longevity to the ideas of both scientists. The results are inconclusive, but they prove that they can have a certain level of truthfulness.

Miller and Urey experiment

This experiment is considered one of the classic tests of the investigation of abiogenesis processes. It was carried out in 1952 by the professor of the University of Chicago (and precursor of the atomic bomb) Harold Urey; and one of his students, Stanley Miller.

The experiment was carried out using methane, hydrogen, water and ammonia. All the compounds were sealed within a sterile environment, where everything was controlled to simulate the conditions of the Earth millions of years ago.

The evaporation of the water was induced and electricity was used to simulate the possible impacts of atmospheric electric discharges.

This experiment succeeded in producing a variety of amino acids that partially supported the theory of the primordial soup and, therefore, the process of abiogenesis. They were not conclusive evidence, but they definitely indicated a latent possibility that life on Earth could have been originated in this way.

However, other scientific tests that were carried out years after the experiment concluded that the Earth's atmosphere at that time could have been very different from what was proposed in the Miller and Urey experiment. This affected the credibility of the theory.

Experiment by Joan Oró

Oró was a French scientist who carried out an experiment in 1961. He determined that the nucleobase adenine (a fundamental component of nucleic acids present in living organisms) could be created from hydrogen and ammonia in a water solution.

His experiment remains a standard of prebiotic chemistry to this day, partially supporting the theory of prebiotic soup.

Prayed also proposed the idea that the fundamental components of life came to Earth through comets and asteroids that hit the planet millions of years ago. His idea is widely accepted; In fact, it is believed that this is the most feasible way by which life on Earth originated.

This theory was also generated in 1961, when he carried out his experiment. In fact, according to Oró, the components by which life was generated by means of abiogenesis reached the prebiotic water through comets that impacted the planet.

References

1. The secret ingredient to early life's primordial soup: Thickener, Sarah Kaplan for the Washington Post, October 10, 2016. Taken from washingtonpost.com
2. Finding the Origin of Life: The Primordial Soup Theory Explained, (n.d.). Taken from biologywise.com
3. Primordial Soup, Wikipedia en Español, March 29, 2018. Taken from wikipedia.org
4. Miller-Urey Experiment, Wikipedia en Español, February 22, 2018. Taken from wikipedia.org
5. Joan Oró, Wikipedia en Español, November 26, 2017. Taken from wikipedia.org
6. Harold Urey, Wikipedia en Español, April 2, 2018. Taken from wikipedia.org