English: A schematic representation of the classical RNA world hypothesis. Initially, synthesis and random polymerisation of nucleotides result in pools of nucleic acid oligomers, in which template-directed non-enzymatic replication may occur. Recombination reactions result in the generation of longer oligomers. Both long and short oligomers can fold into structures of varying complexity, resulting in the emergence of functional ribozymes. As complexity increases, the first RNA replicase emerges, and encapsulation results in protocells with distinct genetic identities capable of evolution. In reality, it is likely that multiple processes occurred in parallel, rather than in a strictly stepwise manner, and encapsulation may have occurred at any stage.