Scientists have used a number of model systems to try to simulate conditions under which the first biological polymers might have been made. Each of these systems is based on several observations and speculations:
Solid mineral surfaces, such as powderlike clays, have large surface areas. Scientists speculate that the silicates in clay may have catalyzed (sped up) the condensation reactions that resulted in organic polymers.
Hydrothermal vents deep in the ocean, where hot water emerges from beneath Earth’s crust, lack oxygen gas and contain metals such as iron and nickel. In laboratory experiments, these metals have been shown to catalyze the polymerization of amino acids in the absence of oxygen.
In hot pools at the edges of oceans, evaporation may have concentrated monomers to the point where polymerization was favored (the “primordial soup” hypothesis).
In whatever ways the earliest stages of chemical evolution occurred, they resulted in the emergence of monomers and polymers that have probably remained unchanged in their general structures and functions for several billion years.