Biodiversity Part One

In his book "The Greatest Show on Earth", Richard Dawkins discusses the mountain of evidence supporting evolution.

One of the interesting points he makes is that despite the MANY other forms of evidence for evolution, undeniably the strongest evidence comes from the biodiversity of life, also called the geographical distribution of life - how species are nearly universally constrained to relatively small geographical niches. That CANNOT be explained by Biblical creationism and, because of that, is a topic that creationists really refuse to even discuss.

Dawkins makes his points primarily in chapter 9 of his book:

“It is almost too ridiculous to mention it, but I’m afraid I have to because of the more than 40 per cent of the American population who, as I lamented in Chapter 1, accept the Bible literally: think what the geographical distribution of animals should look like if they’d all dispersed from Noah’s Ark. Shouldn’t there be some sort of law of decreasing species diversity as we move away from an epicentre – perhaps Mount Ararat? I don’t need to tell you that that is not what we see.

“Why would all those marsupials – ranging from tiny pouched mice through koalas and bilbys to giant kangaroos and Diprotodonts – why would all those marsupials, but no placentals at all, have migrated en masse from Mount Ararat to Australia? Which route did they take? {269} And why did not a single member of their straggling caravan pause on the way, and settle – in India, perhaps, or China, or some haven along the Great Silk Road? Why did the entire order Edentata (all twenty species of armadillo, including the extinct giant armadillo, all six species of sloth, including extinct giant sloths, and all four species of anteater) troop off unerringly for South America, leaving not a rack behind, leaving no hide nor hair nor armour plate of settlers somewhere along the way? Why were they joined by the entire infraorder of caviomorph rodents, including guinea pigs, agoutis, pacas, maras, capybaras, chinchillas and lots of others, a large group of characteristically South American rodents, found nowhere else? Why did an entire sub-order of monkeys, the platyrrhine monkeys, end up in South America and nowhere else? Shouldn’t at least a few of them have joined the rest of the monkeys, the catarrhines, in Asia or Africa? And shouldn’t at least one species of catarrhine have found itself in the New World, along with the platyrrhines? Why did all the penguins undertake the long waddle south to the Antarctic, not a single one to the equally hospitable Arctic?

“An ancestral lemur, again very possibly just a single species, found itself in Madagascar. Now there are thirty-seven species of lemur (plus some extinct ones). They range in size from the pygmy mouse lemur, smaller than a hamster, to a giant lemur, larger than a gorilla and resembling a bear, which went extinct quite recently. And they are all, every last one of them, in Madagascar. There are no lemurs anywhere else in the world, and there are no monkeys in Madagascar. How on Earth do the 40 per cent history-deniers think this state of affairs came about? Did all thirty-seven and more species of lemur troop in a body down Noah’s gangplank and hightail it (literally in the case of the ringtail) for Madagascar, leaving not a single straggler by the wayside, anywhere throughout the length and breadth of Africa?

“Once again, I am sorry to take a sledgehammer to so small and fragile a nut, but I have to do so because more than 40 per cent of the American people believe literally in the story of Noah’s Ark. We should be able to ignore them and get on with our science, but we {270} can’t afford to because they control school boards, they home-school their children to deprive them of access to proper science teachers, and they include many members of the United States Congress, some state governors and even presidential and vice-presidential candidates. They have the money and the power to build institutions, universities, even a museum where children ride life-size mechanical models of dinosaurs, which, they are solemnly told, coexisted with humans. And, as recent polls have shown, Britain is not far behind (or should that read ‘ahead’?), along with parts of Europe and most of the Islamic world.

“Even if we leave Mount Ararat to one side; even if we refrain from lampooning those who take the Noah’s Ark myth literally, similar problems apply to any theory of the separate creation of species. Why would an all-powerful creator decide to plant his carefully crafted species on islands and continents in exactly the appropriate pattern to suggest, irresistibly, that they had evolved and dispersed from the site of their evolution? Why would he put lemurs in Madagascar and nowhere else? Why put platyrrhine monkeys in South America only, and catarrhine monkeys in Africa and Asia only? Why no mammals in New Zealand, except bats who could fly there? Why do the animals in island chains most closely resemble those on neighbouring islands, and why do they nearly always resemble – less strongly but still unmistakably – those on the nearest continent or large island? Why would the creator put only marsupial mammals in Australia, again except bats who could fly there, and those who could arrive in man-made canoes? The fact is that, if we survey every continent and every island, every lake and every river, every mountaintop and every Alpine valley, every forest and every desert, the only way to make sense of the distribution of animals and plants is, yet again, to follow Darwin’s insight about the Galapagos finches: ‘One might really fancy that from an original paucity . . . one species had been taken and modified for different ends.’”