between different replicators. Natural selection arises if one type
reproduces faster than another type, thereby changing the
relative abundances of these two types in the population. Natural
selection can lead to competitive exclusion or coexistence. In the
present theory, however, we encounter natural selection before
replication. Different information carriers compete for resources
and thereby gain different abundances in the population.
Natural selection occurs within prelife and between life and
prelife. In our theory, natural selection is not a consequence of
replication, but instead natural selection leads to replication.
There is ‘‘selection for replication’’ if replicating sequences have
a higher abundance than nonreplicating sequences of similar
length. We observe that prelife selection is blunt: Typically small
differences in growth rates result in small differences in abundance.
Replication sharpens selection: Small differences in
replication rates can lead to large differences in abundance