FOR A FULLY operational genetic system to develop, emerging life had to become partitioned into a population of protocells capable of multiplying by division, so that protocells, not simply molecules, henceforth were subjected to natural selection. So far, we have been content to assume that this partitioning took place. Let us now turn back in time and look into the mechanisms of cellularization and into the new properties that the confinement of life within boundaries both allowed and required.
There are two conflicting views of the time at which the first cellular structures appeared. A number of scientists, impressed with the fact that microscopic aggregates or vesicles of various kinds, crudely reminiscent of living cells, can be observed to form under relatively simple conditions, believe that the formation of primitive cells was the seeding event in the origin of life. Extensive laboratory investigations--by Alexander Oparin in Soviet Russia,1 Alphonse Herrera in Mexico,2 and Sidney Fox in the United States,3 to mention only the most prominent-- have been devoted to such artificial "cells," though without disclosing any plausible pathway for the progressive "vitalization" of the structures. Other scientists have defended early cellularization on the grounds that a membranous structure was required for the initial trapping of sunlight energy.4 Yet others find unacceptable for theoretical reasons the possibility that life could have originated in an unstructured "soup."5
The opposite view is also defended by many. It has been pointed out that the "primeval soup" need not have filled the whole of oceans. Coastal areas, lagoons, ponds, even puddles, could have provided appropriate sites for the soup to thicken