English: Hypothetical evolutionary landscape. The horizontal axes represent the biological parameters being measures (i.e. component of phenotype, genotype, nucleotide sequence combinations) and the vertical axis represents fitness. This particular landscape is an exaggerated example of Gavrilet's holey landscape. The (blue) surfaces represent hypervolumes of neutral fitness networks. In other words, a change in the parameter of interest doe not result in a change in fitness, most of the time. The empty spaces are low fitness areas that cannot be easily crossed. (In Gavrilet's models, the netural fitness hypervolumes are larger and the holes smaller.) If a population is lucky, it will stumble upon a pathway leading to a higher fitness hypervolume.