On: Archaea: The 'Dark Matter' of the Microbial World

[pygy_]

In general, geographic separation leads to speciation. It can be rivers (IIRC for example bonobos and chimpanzees live on different sides of the Congo river).

Another interesting example is I think seagulls along the arctic circle that are split in many species spread along an east-west axis. Most species can interbreed with their immediate neighbour, but not the neighbour of their neighbour (except at one point where the extreme populations meet and the immediate neighbours are not compatible either).

[ihartley → pygy_]

If anyone else is curious, this is called a ring species, and there are only four known examples: https://en.wikipedia.org/wiki/Ring_species

[delhanty → ihartley]

>non-breeding, though genetically connected, "end" populations may co-exist in the same region

This reminds me of the Riemann surface associated with the complex logarithm:

https://en.wikipedia.org/wiki/Complex_logarithm#The_associat...