Re: Tiktaalik, Great Danes and speciation

[David Marjanovic <david.marjanovic@gmx.at>]

> Maybe the Biological Species Concept, if applied consistently, is not such 
> a bad idea bad at all (well, for animals at the species and genus level, 
> plants would be a bit more difficult). Not perfect, but at least as 
> unambiguous, objective and unarbitrary as many other diagnostic traits.

Unfortunately the ability to interbreed is always a plesiomorphy. This 
sounds like a merely philosophical problem -- but it's a practical one.

There are a few fish species in a couple of lakes in Nicaragua or Panama or 
something...

--+--A
  `--+--B
     `--+--C
        `--+--D
           `--E

A and E can interbreed. All other combinations can't.

The discoverer proposed the ecological species concept, IIRC.