Reply to Northwind When you say, "However, diversity of traits does not in and of itself equal greater evolution," it is confusing. Increase in genetic variability is evolution, decrease in genetic variability is evolution, changes in allele frequencies is evolution. Greater evolution??? Don't know what that means. What is greater evolution? Your comment on an "evolutionary dead end" is controversial. Small groups that become isolated have tremendous decreases in genetic variation as a consequence of what are termed 'population bottlenecks.' With no genetic diversity these groups are less able to adapt to environmental change, but this is true of any group with low genetic variability and is not necessarily indicative of isolation. Theories of speciation all use isolation as a requisite (exception: some evidence for sympatric speciation). Isolated populations (such as island populations) can become over-specialized in some ecological aspects, but this does not necessarily mean that they are in an evolutionary dead end.