The Primordial Soup Theory

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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,[14][15] 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 species.

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:

Methane (CH4)

Ammonia (NH3)

Water (H2O)

Hydrogen (H2)

No Oxygen

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:

Electricity

Ultraviolet light

Heat

Shock

This theory emphasize metabolism because of the cooperative group of molecules and how they gain and use energy and

molecules.

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.

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