[autumnraine]

So an entirely new species would not be created, they would just be genetically incompatible with others? I mean they would still be a robin and an owl, but adapted for their environment, right? You said “What visible changes might accompany those changes would depend on how different the survival traits optimized for the island were from the survival traits optimized for the mainland.”

That is adaption, right? It is not a robin turning into an entirely new creature. Just a genetically adapted to the environment robin.

[CaptRon]

Uh, that’s what Darwin found on the Galapogos Islands.

[Phileleutherus Franciscus]

That is adaption, right? It is not a robin turning into an entirely new creature. Just a genetically adapted to the environment robin.

This comes down to the definition of a species. A common definition of a species (though it is a bit fuzzy here and there, see liger) is one which cannot or will not interbreed to produce fertile, viable offspring. Let's drop robins and look at something that may be easier to see. Are American mountain lions and, for example, cheetahs merely variations on the theme of big cat, or seperate species? How about hippopotami and whales?