  All life, including cells and artificial protocells, must integrate diverse
molecules into a single unit in order to reproduce. Despite expected pressure
to evolve a simple system with the fastest replication speed, the mechanism by
which the use of the great variety of components, and the coexistence of
diverse cell-types with different compositions are achieved is as yet unknown.
Here we show that coexistence of such diverse compositions and cell-types is
the result of competitions for a variety of limited resources. We find that a
transition to diversity occurs both in chemical compositions and in protocell
types, as the resource supply is decreased, when the maximum inflow and
consumption of resources are balanced.
