Multiplicity of species in some replicative systems

In an attempt to explain the uniqueness of the coding mechanism of living cells as contrasted with multi-species structure of ecosystems we examine two models of individuals with some replicative properties. In the first model the system generically remains in a multi-species state. Even though for some of these species the replicative probability is very high, they are unable to invade the system. In the second model, in which the death rate depends on the type of the species, the system relatively quickly reaches a single-species state and fluctuations might at most bring it to yet another single-species state.