Fox hypothesizes that proteinoid material first polymerized on
hot, dry volcanic cinder cones, and then was leached into the oceans
by rain to form microspheres, which then could have become the early
segregated chemical systems that eventually led to protocells.
This cinder cone hypothesis, while ingenious, is not accepted
by many scientists as more than an interesting idea.
What has been demonstrated is that membrane formation, swelling,
budding, and division all can occur by physical chemical forces,
and are not necessarily tied in with living organisms.
A weakness of the theory is the requirement of dry heat for polymerization.
It is hard to imagine such high concentrations of dry amino acids
occurring on the early planet.
It is difficult to make roast beef out of Haldane soup.
Various mechanisms have been suggested by which amino acids could
be induced to polymerize spontaneously, even in an aqueous environment.
These mechanisms usually involve making intermediate molecules
with high free energy, and using this free energy to bring about
the joining of amino acids during the polymerization process.
Such mechanisms are analogous to the priming of molecules with
phosphate groups or coenzymes, which we have seen in glycolysis
and the citric acid cycle.
While the problem of natural formation of protein chains by abiotic
means has not been solved completely, we tend to think of it as
No matter how an early proteinoid polymer might have been formed,
Fox's microsphere experiments, divorced from their volcanic cinder
cone hypothesis, remain relevant as a possible way of producing
isolated, enclosed regions of aqueous solution for further evolution.