Look, like everyone else I have no trouble dismissing creationists as bat-shit crazy religious fundamentalists who wouldn't know a scientific fact if the ghost of Richard Feynman bit them on the backside. No trouble at all, and I am always happy to join in a little gentle poking of a stick through the bars on the megachurch windows and stirring things up a bit. But while that gives me a nice warm glow of mental superiority to go with my first cup of morning coffee, it really avoids the question of how the creationist/ID crowd find it so easy to convince these simple people that up is down, night is day.
And I guess the answer, reluctantly (as I drink my second cup of morning coffee), is that it is the fault of most of us who write about Darwinism. The mistake, the original sin, is that we have talked about species evolving when we have talked about evolution. An easy mistake to make, and you can see why we made it, but it has proved fatal.
As soon as you understand this you understand why the babble of creationists, as apparently as mindless as "speaking in tongues", is actually based on a fundamental educational failure, and a consequent fundamental misunderstanding.
The two commonest glossolallies are "where are the transitional fossils?" and "if humans evolved from apes why are apes still around?" They don't ask these questions merely to annoy (although it is a bonus), but because they genuinely think these are points to be considered. And the fact that they can ask such questions, 150 years after "The Origin of Species", 150 years of tens of thousands of biologists and paleontologists, and geologists, and chemists, and botanists studying every aspect of evolutionary theory, and after being schooled in scientifically advanced western countries, is a sign of our collective failure.
All of us, creationists and rational people alike, understand how the first organism evolved out of the primordial soup by a process of natural selection gradually producing a bundle of self-reproducing chemicals, no argument there. And it is a sign of Darwin's genius that he understood a process that could lead from inorganic chemicals to organic life forms without any need for an imaginary friend to send a lightning bolt from out-stretched finger. But it is what we say about what happens next that has left us still having to debate Robert Chambers one and a half centuries after his theories should have been buried without a vestige remaining.
If these people who start creation museums (yet another oxymoron) had as much intelligence as a neanderthal they would ask not why apes are still with us but why, if all life on Earth evolved from the very first bacterium swimming in the primordial ooze, do we still have bacteria today?
In a sense "natural selection" is the least important of Darwin's ideas. Oh sure, it's not bad, but it's so obvious that I don't know why I didn't think of it. But the far more vital part of evolutionary theory (or "Darwinism", as the evangelicals call it, if any creationists are still reading) is the idea of allopatric speciation. Never heard of it? No, and that is the problem.
Allopatric speciation is simply this - if one part of a species becomes separated by a geographic barrier (a mountain range forms, sea level rises, a desert comes into being, a river changes course, a landslide falls, a continent moves, a glacier extends), and stays separate long enough, then its members will no longer be able to breed with the other part of the population and it will therefore have become a different species.
Doesn't matter why it becomes different - just an accumulation of mutations might do the trick, hell Lamarckism would do the trick. But in fact Darwin had this one pegged - natural selection, acting on variation within the two populations, causes them to diverge. And the more different to the original environment is the place in which the second population lives, the more adaptation will occur, and the more the second species will differ from the first. And, in turn, as further changes in the land occur, these two species can in turn split, and so ad infinitum.
So this is the answer to the questions that so furrow the low brows of our primitive fundamentalist cousins. Both the original species and the separated species can (and often do) go on surviving side by side. The "human" population somehow got separated from the "chimpanzee" population, one took the high road and one took the low, but both made it all the way to 2009. Sometimes though, one or more of the subsequent species become extinct for all sorts of reasons, and if their fossils don't survive we may never know of their loss.
And astute readers (the creationists have all turned off the lights and left the building now) will have seen that this pattern of speciation makes the concept of "missing links" meaningless. You could, with a time machine, trace back through every chimpanzee generation to the chimpanzees of, say, 5 million years ago. And you could do the same with human generations. And replaying the process backwards you would see these two populations become gradually identical and then merge into one (and further back you would see that population merge with the orangutan one, and so on). There would be no gaps, no missing links, no opportunity for missing links. Play it back the two populations become one, play it forward they become two, play it as many times as you like, Sam, and the process of speciation remains the same.
And the process happens no matter how different or similar the resulting species are. Chimpanzees might well have become more bipedal more naked apes, humans might well have remained as hairier less bipedal ones. The reasons they, we, look like we do now is bound up in the climatic and geographic fluctuations of long ago Africa.
So if I was writing biology text books for use in Texas or Kentucky or Missouri schools I think I would join their education authorities in demanding that the word evolution not be mentioned. Instead I would put all of my effort into explaining speciation. Show how that original bacterium could become 2, 4, 8, 20, 30, 60 ... species. Could become, even after losing tens of thousands of species along the way, the tens of thousands of species, including humans, chimps, and bacteria, we see today. Explain about the movements of continents, and climate change, and its effects on both the origin and demise of species. You will find they will know about climate change in the past as a result of another misinformation campaign, but it will come in useful here.
And by teaching, over and over, the mind numbingly obvious process of speciation you will cut off the oxygen from the creationists who want to keep children ignorant of the origins of the astonishingly diverse plants and animals we see today. Give them the sense of grandeur in this view of life on this planet.
The Watermelon Blog, as those adapted to it know, has a certain grandeur all of its own.