f1a32aee_Evolutionary_physiology__Event
[Date] Between 4500 and 3500 Ma [Event] 
The earliest life appears, possibly derived from self-reproducing RNA molecules.The replication of these organisms requires resources like energy, space, and smaller building blocks, which soon become limited, resulting in competition, with natural selection favouring those molecules which are more efficient at replication. DNA molecules then take over as the main replicators and these archaic genomes soon develop inside enclosing membranes which provide a stable physical and chemical environment conducive to their replication: proto-cells.
Evolutionary physiology
Event