I was reminded of one of the more comical, but persistent misconceptions by creationists in a thread on Internet Infidels, on The Coelacanth. Try doing a google search for “coelacanth creation” and be amazed at the volume of ignorance pumped out on this subject. I’ve also run across a more recent example of the misrepresentation of the coelacanth that I’ll mention later … this poor fish has a long history of abuse by creationists, though, so here’s a brief rundown of wacky creationist interpretations.
Evolutionary scientists used to think that amphibians evolved from a group of fishes that included the coelacanth, which was known only from fossils. But they dropped this idea when living coelacanths were found from 1938 showing no evidence of evolution from the oldest fossil coelacanths to the living examples.The evidence from the coelacanth is good evidence for creation, for it shows that DNA, the genetic code, has remained stable throughout time.
The fossil record, with its lack of intermediate forms and its unchanging biota such as the coelacanth, falsifies evolution.
Some animals and plants have remained unchanged for literally hundreds of millions of years. These “living fossils” can be more embarrassing for the evolutionist than they often care to admit. One creature in particular, the coelacanth, is very instructive. The first live coelacanth was found off the coast of Madagascar in 1938. Coelacanths were thought to be extinct for 100 million years. But most evolutionists saw this discovery as a great opportunity to glimpse the workings of a tetrapod ancestor. Coelacanths resemble the proposed ancestors of amphibians. It was hoped that some clues could be derived from the modern coelacanth of just how a fish became preadapted for life on land, because not only was there a complete skeleton, but a full set of internal organs to boot. The results of the study were very disappointing. The modern coelacanth showed no evidence of internal organs preadapted for use in a terrestrial environment. The coelacanth is a fish–nothing more, nothing less. Its bony fins are used as exceptionally well-designed paddles for changing direction in deep-sea environment, not the proto-limbs of future amphibians.
Living coelacanths revealed how groundless the speculation regarding them was. Contrary to what had been claimed, coelacanths had neither a primitive lung nor a large brain. The organ that evolutionist researchers had proposed as a primitive lung turned out to be nothing but a fat-filled swimbladder. Furthermore, the coelacanth, which was introduced as “a reptile candidate preparing to pass from sea to land,” was in reality a fish that lived in the depths of the oceans and never approached nearer than 180 meters from the surface.
All of the above sites and quotes are odious nonsense. Any time a creationist tries to tell you that “living fossils” disprove evolution, you know that he or she a) doesn’t understand the theory of evolution at all, and b) hasn’t honestly looked at the evidence they think they are presenting. They might as well get the word “Idiot” tattooed into their forehead; as a signifier of their intellectual prowess, it would be just as accurate. They all make several gross errors.
“Unchanging forms” refute evolution. Not quite true. A species that exhibited no variation at all, and that showed no change over time, not even neutral molecular differences, would be a major puzzler for biology. No such thing has ever been observed. On the other hand, gross structural stasis over a long period of time is no problem for evolution. One thing even many biology students have some difficulty grasping is that selection is a conservative force; it tends to limit variation to the narrower domain of the viable and the competitive.
Coelacanths are unchanging forms that show no evidence of evolution. Read the quotes above: the creationists can’t even get their stories straight. They repeatedly claim that the coelacanth is “stable” and “unchanging”, but then they turn around and point out huge differences between what we know of coelacanths in the fossil record and modern forms: they live in different environments with remarkably different physiology. Which is it? Are they unchanging or are they radically changed?
The answer is that modern coelacanths are specialized remnants of a once diverse and widespread group. They have changed extensively over hundreds of millions of years, as would be expected, and this once widely successful and branched family has been pruned back to just a few twigs lurking in relatively inaccessible locations. Here, for instance, are a few fossil examples of ancient coelacanth diversity (Clack, 2002):
“Coelacanth” is a term that refers to an entire order of fish, the Coelacanthiformes. The modern coelacanths are of the genus Latimeria, and none of the ancient fish belong to that genus—it ought to be fairly obvious that Latimeria is clearly distinct from any of the fossil forms if it was assigned to a unique genus. The brilliant creationists who point to Latimeria and claim that it is an example of an unchanging form might want to reconsider; would they also point to a random member of the primate order, say a howler monkey, and announce that it is obvious that all primates for all of their history have been identical?
Scientists haven’t been disappointed by the coelacanth at all. It’s wonderful to have at least a few representatives of a family once thought to be extinct that are still around. Personally, one thing I’d like to know more about is that fascinating limb duplication they exhibit. They have a second dorsal and anal fin that each have a partial girdle structure—there’s an interesting story in molecular development in there, I’m sure.
(By the way, the web isn’t entirely a morass of inanities about coelacanth evolution. Wesley Elsberry, Mark Isaak, and Don Lindsay all say eminently sensible things on the subject…but then, they aren’t creationists.)
Clack, J (2002) Gaining Ground: the Origin and Evolution of Tetrapods. Indiana University Press, Bloomington.