Staracle - Evolutionary Algorithms - Staracle International (original) (raw)

Several factors govern the course of the evolution process. The {\em mutation} determines how genes are mutated from one generation to the next. A mutation in nature always targets the genotype, i.e., the mutation varies the genes of an offspring. Some of these variations will then alter the phenotype of the new individual, which has an impact on the second important factor, namely the selection. The selection process determines which individuals are chosen to reproduce for the following generation. In nature, it is likely that individuals with a high fitness will mate, but also individuals with a low fitness value have a chance of creating offsprings. The third major factor is the recombination, often referred to as crossover. It determines how the genomes of two individuals are merged during the mating process.

Besides these important factors, a large number of other factors influence the evolution. In nature, the phenomenon of co-evolution plays a significant role. It refers to the mutual dependence of different species, such as for example in predator--prey relationships. Furthermore, the inner structure of a population is important. Natural populations are often divided into smaller sub-populations (called demes), separated by rivers or mountain ridges. A limited exchange of genetic information takes place by migration of individuals from one sub-population to the other.

It is obvious that the evolution as described above involves a large amount of randomness. This applies, among others, to the mutation, the crossover, and the selection. Therefore, the offsprings of a certain generation are random to a certain degree. However, this randomness is channelized due to the inheritance of features from one generation to the next. Colloquially, one could therefore describe the evolution process as structured probing of the possible solution space.