Why is bio-geography the least mentioned "evidence" in most debates about evolution and creation?

Question

If you read Darwin's "The Origin of Speicies" as well as many of his supporting works, it is quite clear that patterns of habitation by closely related plant and animal species was the primary factor driving him to reject special creation and argue for the evolution of species from a common ancestor. In fact, this was his only real clue as analysis of fossil records were embryonic and concepts like genetics and molecular biology didn't even exist.

Today, however, aside from throw away lines about Finches on the Galopogas islands, virtually no one even mentions this concept anymore.

With all the use of global information systems and things like Google Earth, are defenders of evolution overlooking what might be a powerful and straightforward way of demonstrating the realities of evolution on the ground?

As noted, Darwin's assumptions about bio-geography weren't always correct given later developments, but even given the msises, it is undeniable that this is what him thinking down the right path.

When done properly and accurately, this kind of material can go much further than comments abotu 97% genetic similarity in "opening the eyes and minds" of those who just haven't given it much thought vs. the "true believers".

I'm wondering why no one has tried to develop a more "up to date" set of materials to help make the case.

Answer 1

Nope. Biogeography was actually the weakest thread in Darwin's thesis, and the first to be falsified comprehensively. It remains just as weak today.

The main points Darwin failed to appreciate is that landmasses are not stationary, and that animals have astounding powers of dispersal. So for example he wondered over the floristic similarity between Australia and Southern Africa. And he suggested that animals and plants travelled over the Antarctic ice sheets to explain the similarities of Australia, South America and New Zealand, which is clearly absurd.

Of course we now know these things are due to continental drift. But in order to accept continental drift as an explanation for such distant landmasses being biologically similar we need to first accept an ancient and gradually changing Earth, and anyone who accepts an ancient and gradualy changing Earth already accepts evolution to greater or lesser degree.

Similarly Darwin failed to understand that South Americas rodents and monkeys didn't evolve on that continent, or travel their via Asia and North America. They travelled directly across the Atlantic Ocean on rafts all the way from Africa. As unlikely as that seems that is what the genetic and fossil evidence tells us. Because we can prove that such long-distance oceanic dispersals have occurred multiple times largely destroys any utility of biogeography as a prop for natural selection. If animals can raft thousands of miles across open ocean between continents then it seems ridiculous to suggest they never made it to the Galapagos islands. And if species are regularly travelling between distant landmasses then biogeography tells us nothing except that many species are incapable of surviving on islands. something that nobody disputes.


Edit
Silver Birch, rodents and primates travelled to South Am when it was already separated from Africa by AT LEAST 1, 500 km of open ocean. If we are to accept evolution at all then we need to accept that fact.

But if we accept that fact then biogeography has no utility at all in this discussion. If we accept that animals can make multiple trans-continental crossings then the Galapagos or the Wallace line tells us approximately nothing except what can survive in the landing zones.

Answer 2

I'm about two-thirds of the way through "The Origin of Species" right now (it's slow going), and I must admit I'm impressed with Mr. Darwin. He certainly was a keen observer of similarities and differences in flora and fauna, and it seems he had a network of correspondents all over the world.

I'm reading it because I wanted to see for myself what the fuss was all about.

It's true that Darwin didn't know about mitochondrial DNA, nor did he know about continental drift. But he was tuned in to climate change, and what happens when one species -- plant or animal -- invades the turf of another.

His mantra seemed to be "natural selection" (a/k/a "survival of the fittest") whereby species adapt to changing environments. Those that successfully adapt ("evolve") survive, and those that don't, become extinct.

Since I'm not a "life sciences" person, I don't know the current status of Darwin's approach. From what I'm reading, though, he seems pretty persuasive to me.

Answer 3

I'll vote that a good question. I never tend to use it. Maybe we have just got too clever. They also tend to get wrapped up in ring species.

A point to leviter_atingere
Africa and South America may have separated as recently as 95 million years ago. there would not have been a requirement to raft thousands of miles. Early primates and rodents wouldn't of had to get their feet wet.

Answer 4

Because it sucks and darwin was wrong...