How can the founder effect lead to evolution

How can the founder effect lead to changes in the gene pool? The new gene pool may therefore start out with allele frequencies diffrent from those of the parent gene pool ... If a population is not evoloving, allele frequencies in its gene pool do not change, which means that the population is in genetic equilibrium.

In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. In extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species. No duh : D