lpetrich

This is an area that creationists are reluctant to make a big issue out of, at least in their public posturing, because I suspect that biogeography is an embarrassment for them. They can seem half-plausible when they try to argue that evolution could not have happened, but they don't have any comparable case with biogeography.

One interesting side effect of the voyages of exploration was the discovery that species typically have ranges that are not as large as they are capable of having; sometimes much smaller ranges. This was often apparent with introduced species, which would sometimes become too successful; consider rabbits in Australia. Charles Darwin himself had gotten direct acquaintance of that in his voyage aboard the Beagle; he commented that Australia vs. the rest of the world might be interpreted as "two Creators at work".

And such a hypothesis was indeed proposed in the mid-18th cy., that there had been several "centers of creation" on our planet. Dispersion from Mt. Ararat involved a host of implausibilities, which I will skip to save space. But to account for more and more biogeographical details, these centers multiplied.

Back to Charles Darwin. He explained how evolution can account for the distinctive biotas of oceanic islands, which consist of the sort of organisms that can successfully travel to those islands without outside intervention. He noted numerous reports of floating vegetation in oceans, and he did experiements on how well seeds can survive in seawater. Thus, he concluded that islands can easily get a lot of plants growing on them soon after they are formed. Turning to the animal kingdom, he noted that the distinctive faunas of oceanic islands are closely related to either flying animals (birds, bats, insects) or to slow-metabolizing animals (turtles, lizards). Fast-metabolizing land animals on these islands were all flightless birds, which can easily be descended from flying ones.

Imagine a log with some turtles and some mice in it that floats down a river into the sea. The mice starve after a few days or weeks from lack of food, because of their high metabolism, while the turtles slow done and snooze. When the log washes up on some island, the turtles sniff the vegetation and crawl to it from the log, leaving the dead mice behind, or at least the dead mice they have not already eaten.

One reasonably concludes that the creative power that produced those species was either limited by the species' putative ancestors' ability to travel or else had decided to imitate that limitation. The latter hypothesis, it must be said, is Philip Gosse territory.

And natural selection satisfies that limitation very well.

This also holds true of the biotas of larger landmasses; there are numerous examples of this, like Australia, but my patience is running out.

And even within big, continuous habitats, the species with the bigger range are the species that can more easily travel.

By comparison, creationists and IDers have had very little to say.