Darwin Misses a Link (to Florida)

February 12 was the anniversary of Charles Darwin’s birthday--Happy 206th, Chuck!!. Around the world, scientists raised their glasses and toasted the man who, among other achievements, developed the theory of evolution by natural selection. He based this concept largely on observations he made during a five year voyage of the South Seas aboard the HMS Beagle.

When he first proposed the theory in his 1859 book, On the Origin of Species, people were aghast. The thought that all animal species (including humans) evolved from a common ancestor was more than most people were able or willing to accept. Today, however, scientists, theologians and most of the educated world have come to accept evolution as fact (Oh, hi Kansas; didn’t see you there. How’s the corn and all? No, we’re not talking about you. Gotta go!) 

The concept of evolution has broad appeal, being relevant to a wide range of interests including, animal behavior, anatomy, human sociology, psychology, and all other sciences. It helps that it is more easily understood and observable, and yes, maybe even a bit more exciting than most other sciences (Oh, hi chemistry, when did you get here? How’s the old pH doing? Wow, look at the time! See ya!)

In recent years, especially since the lead-up and celebration of Darwin’s 200th birthday in 2009, so-called “Darwin tours,” have become increasingly popular. If I know the most highly evolved species on the planet (and I think I do), I'm guessing the anniversary inspires herds (flocks?) of Orvis-shod evo-tourists to descend upon Darwin sites throughout the South Seas. At this moment, they're probably scrambling over the rocky, Galapagos landscape after giant land tortoises, while, on St. Jago they are gazing up at the cliffs where Darwin pondered exposed marine fossils; they’re scratching the ground in Patagonia for fossils of Megatherium (a giant, ice-age ground sloth); stalking foxes on the Falklands; and traipsing the wilds of Chile in search of mockingbirds. And, everywhere, they’re marveling at Darwin's genius and the wonders of evolution.

Unfortunately, most of us won’t be able to visit the famous Darwin sites (survival of the fattest wallet). But, don’t worry, if you want to marvel at the workings of evolution, we have some striking examples right here in North Florida. In fact, if Darwin had directed his explorations to our humble neck-of-the-woods, he could easily have seen similar animals and made some of the same observations he made in the South Seas. He could have found Megatherium fossils in the Ichetucknee limestone and marine fossils in the rocky bluffs flanking the Suwannee. And, yes, he might have even seen a mockingbird or two.

One thing Darwin would not have found here are marine iguanas. The closest thing we have are alligators. That could have been a problem. At one point, Darwin decided to see how long an iguana could stay under water without breathing. So, following normal protocol of good scientific inquiry, he tied a rock to an iguana and chucked it into the sea. When he pulled it up an hour later it was still alive. He was very relieved… as was Darwin. On another occasion he grabbed an iguana by the tail and tossed it (sans rock, this time) into the water to see how well it could swim. If he had tried such experiments on our own big “lizards,” it might not have gone so well. He might have been eligible to be the first recipient of the Darwin Awards. Although if that had happened, he never would have written his book, and there would be no such award and therefore…. (How’s that for a paradox!)

In the grand scheme of things, Ichetucknee’s biggest disappointment for Darwin would have been the absence of those now-famous finches. After all, without them and their diverse island-based variations, he might never have had the idea of divergent evolution (where separated populations of a single species evolve differently, developing traits best suited to their new environment). Or would he? If he’d come to North Florida and spent some time at the springs (is there any doubt!?) he could easily have made similar observations of a very different species—river snails.

Among the most prevalent (though not always noticeable) creatures in North Florida’s spring-fed rivers, river snails mill about in quiet, barely-moving crowds across gently waving meadows of Vallisneria and Sagittaria. They trek across open sand and scale miniature cliffs. They leave invisible trails across riverscapes of logs, rocks and sunken debris. The abundance of these peanut-sized snails is attributable to two traits common to all Florida spring’s—plenty of calcium (ideal for making strong shells) and an abundance of microscopic algae on which to feed.

River snails are found in all of our springs. And, while they are all superficially similar to the layman’s eye, there are subtle differences from one spring to the next. In fact, many species of river snails are only found in one or two spring runs. It’s divergent evolution at its best. Who needs finches!?

But snails and fossils weren't the only things Darwin would have liked about Ichetucknee. Like many modern-day visitors, Darwin would have enjoyed a cup of “morning Joe.” During his five year exploration around South America, he developed a strong affinity for maté, the caffeine-ladened beverage made from the steeped leaves of Ilex paraguariensis . Here again, we could have accommodated Darwin nicely. Yaupon holly (Ilex vomitoria), a close cousin of maté, is common in the Ichetucknee Forest.  Best of all, it is loaded with caffeine. Like natives for thousands of years, Darwin could have started his day on Ichetucknee enjoying a warm cup of morning “Yo.”