Here is an example of cumulative selection in operation. We start with a random sequence of letters (representing existing or random potential information). We have a target, in this case the sentence “methinks it is like a weasel” (representing the information for some new beneficial feature, like a body organ or a wing). In each generation the existing phrase is ‘breed’ – duplicated with a certain chance of random error in the copying (‘mutations’ are introduced). The ‘progeny’ of the original phrase are examined and the one which most closely resembles the target phrase, however slightly, is kept as the starting point for the next generation (mimicking the process of natural selection).
As can be seen from the slide, it takes only 43 generations for the target phase to be reached.