102 ◾ Biological Computation
• Steady-state selection: In this mechanism only a small fraction of
the population is replaced at every generation, whereas most indi-
viduals continue to live from one generation to the next. Usually
the low-tness individuals are replaced, of course. Aer deciding
which individuals are to be replaced, the next generation’s parents
have to be selected using one of the selection mechanisms so that
new individuals can be created to replace the ones to be eliminated.
In this method the turnover between generations is much more
gradual. It is interesting to note that with this mechanism better
solutions survive from generation to generation without the danger
of crossover.
Each of these mechanisms has ma ...