I am inspired to ask: how many of the regular posters and commenters here have experience of Practical Genetics? By which I mean, have offspring? (Me: guilty, m'lud.)

There seems to be an abundance of diversity stemming from bottleneck migrations to isolated, constricted environments (Galapagos Islands, there's also an article on Panamanian bats in the latest National Geographic) vs bottlenecks resulting from importation to vast new continents. The millions of starlings infesting eastern North America all look alike.

There seems to be an abundance of diversity stemming from bottleneck migrations to isolated, constricted environments (Galapagos Islands, there's also an article on Panamanian bats in the latest National Geographic) vs bottlenecks resulting from importation to vast new continents. The millions of starlings infesting eastern North America all look alike.

the former is adaptive radiation into empty niches. presumably a continent is filled up with a lot of niches, though introduced species might be able to slot into an un or underused once.