"I did not claim that speciation occurs only in founder populations"

Ernst Mayr's quote is a rejection of the idea that speciation only happens in founder populations. He is emphasizing that speciation can occur in any population, not just those that are established by a little number of individuals. This is a crucial point to make, as it highlights the reality that speciation is a natural process that can occur in any population, no matter its size or origin. Mayr's quote likewise serves to remind us that speciation is a complicated process that is affected by a range of aspects, such as genetic drift, natural selection, and geographical seclusion. By denying the idea that speciation only takes place in founder populations, Mayr is highlighting the significance of understanding the different factors that can influence the procedure of speciation.