Haldane and Oparin: Primordial Soup Theory
No new notable research or theory on the subject appeared until 1924, when Alexander Oparin (Aleksandr I. 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
in the early earth had changed, and the presence of living organisms would immediately consume any spontaneously generated
organism. Oparin argued that a "primeval soup" of organic molecules could be created in an oxygen-less atmosphere through
the action of sunlight. These would combine in ever-more complex fashions 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, 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 pre-biotic oceans–very 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.
The Primordial Soup Theory suggests that life began in a pond or ocean as a result of the combination of chemicals from the
atmosphere and some form of energy to make amino acids, the building blocks of proteins, which would then evolve into all
The Primordial Soup Theory states that Life began in a warm pond/ocean from a combination of chemicals that forms amino
acids, which then make proteins. This is suppose to happen at least 3.8 billion to 3.55 billion years ago.
The Russian Chemist A.I. Oparin and English Geneticist J.B.S. Haldane first conceived of this idea. Both developed this
theory independently in 1920.
In this theory, the basic building blocks of life came from simple molecule which formed in the atmosphere (w/o oxygen).
This was then energized by lightning and the rain from the atmosphere created the "organic soup". The first organisms would
have to be simple heterotrophs in order to survive by consuming other organisms for energy before means of photosynthesis.
They would become autotrophs by mutation. Evidence now suggest the first organisms were autotrophs
Chemist Stanley Miller and physicist Harold Urey did a famous experiment in 1950 to test this theory. They mixed gases
thought to be present on primitive earth:
They then electrically sparked the mixture to signify lightning. The results were amino acids, the building blocks of
proteins. It was later discovered that other energies also can excite gases and produce all 20 amino acids:
This theory emphasize metabolism because of the cooperative group of molecules and how they gain and use energy and
In an experiment by Sidney Fox, heated amino acids drove out water as steam and made peptide chains. They were
Proteinoids though, very different from real proteins.