Before revision:  This demonstrates that the introduction of randomness provides an advantage to  mutations in this model, and shows that the advantage increases with the system size  .
After revision:  This demonstrates that the introduction of randomness provides an advantage to mutations in this model, and shows that the advantage increases with the system size . We further demonstrate that the mutants have an advantage in this setting only because they are better at exploiting unusually favorable environments when they arise, and not because they are any better at exploiting pockets of favorability in an environment that is selectively neutral overall .