Hi eniteris! I appreciate your long and detailed responses. Clearly you’ve thought a lot about this topic!
To respond to this point:
”Imagine a forest with one species of frog. Then a road is built through the forest, separating the forest in two. The day after the road is built, I discover that there are now two reproductively isolated groups of frogs! Are these now different species? … No! That’s preposterous.”
If you think this is preposterous because the two populations are not genetically distinct enough, then you are not using reproductive isolation as your definition of species, you are using genetic distinctness. Genetic distinctness COMES from reproductive isolation, but you need to find a definition that you can apply consistently. If you separate two populations so they are reproductively isolated, but you don’t split them into separate species because you actually have a different, more important criteria that they don’t yet satisfy, then reproductive isolation is upstream of your true definition.
If you want a scientific definition, it needs to be consistently applied. If you consistently apply the BSC, then those two frogs would be considered different species. Since I agree that is preposterous, we need to frame our definition more precisely than “potentially interbreeding populations that are reproductively isolated.”
Hi eniteris! I appreciate your long and detailed responses. Clearly you’ve thought a lot about this topic!
To respond to this point:
”Imagine a forest with one species of frog. Then a road is built through the forest, separating the forest in two. The day after the road is built, I discover that there are now two reproductively isolated groups of frogs! Are these now different species? … No! That’s preposterous.”
If you think this is preposterous because the two populations are not genetically distinct enough, then you are not using reproductive isolation as your definition of species, you are using genetic distinctness. Genetic distinctness COMES from reproductive isolation, but you need to find a definition that you can apply consistently. If you separate two populations so they are reproductively isolated, but you don’t split them into separate species because you actually have a different, more important criteria that they don’t yet satisfy, then reproductive isolation is upstream of your true definition.
If you want a scientific definition, it needs to be consistently applied. If you consistently apply the BSC, then those two frogs would be considered different species. Since I agree that is preposterous, we need to frame our definition more precisely than “potentially interbreeding populations that are reproductively isolated.”