The basic structure of an ES is shown in Figure 23 and is very similar to that of a basic GA. One minor change from the standard optimization routine flow diagram is the use of the word `population' rather than `solution'. A more major difference is that the usual operation of generating a new solution has been replaced by three separate activities --- population selection, recombination and mutation. It is in the implementation of these operations that the differences between ESs and GAs lie.
ESs, GAs and associated algorithms are now known collectively as evolutionary algorithms and their use as evolutionary computation. This exciting new field is thoroughly reviewed in much more detail than is possible here in two excellent new publications by Baeck  and Schwefel .
Figure 23: The Basic Structure of an Evolution Strategy.