|Evolution in the News - September 2017|
|by Do-While Jones|
Turtles are slow—but did they evolve slowly?
Turtles are strange creatures unlike any other reptile or amphibian. They are sandwiched between two shells like a clam that has come unhinged. Despite that obvious similarity, no evolutionist thinks turtles evolved directly from a mollusk. That might be the only point of agreement about turtle evolution.
Some evolutionists, Richard Dawkins for example, believe that evolution proceeded gradually through a number of small steps. Other evolutionists, like Stephen J. Gould, believe in punctuated equilibrium—that is, that evolution happened in short bursts separated by long periods of time without any change. These evolutionary jumps are called, “saltations.”
The fossil record is incompatible with gradual evolution. If turtles evolved gradually, then one should find fossils of primitive turtles with partially formed shells which begin a sequence of fossils culminating in modern turtles with fully-formed shells. This isn’t what is found in the fossil record.
Furthermore, a partial shell would not provide much of a survival advantage, so it is hard to argue that natural selection caused bigger and better shells to evolve. That’s why some evolutionists are forced to believe that full-blown turtle shells evolved suddenly in one shot.
The German geneticist, Richard Goldschmidt, used the term “hopeful monster” in his 1940 book, The Material Basis of Evolution. Creationists love to mock this term because it invokes the image of a reptile laying an egg, and a bird hatching from it. Many evolutionists do not take the hopeful monster theory seriously—and for good reason.
But some who have attempted to find an evolutionary explanation for the origin of turtles think that the hopeful monster theory is the least stupid explanation. That brings us to the new book, Turtles as Hopeful Monsters, by Olivier Rieppel, 1 and the resulting reviews of it.
The fossil record has yielded some remarkable examples where a slow transformation has occurred over time, such as the development of hooves in horses. But equally, there are many examples where no such continuous chain exists in the fossil record. Turtles are one such example, as they just suddenly appear in the fossil record, shell and all. Darwin himself attributed this to ‘the extreme imperfection of the fossil record’. This lack of transitional fossils has of course been eagerly exploited by the creationist / intelligent design movement for their own ends.
But ever since Darwin, biologists have argued, and still do, that there exist mechanisms that allow for rapid innovation and saltatory evolution (i.e. evolution by leaps and bounds). This is the emergentist paradigm. 2
Ironically, the example of horse hoof evolution has been discredited by evolutionists since 1951, as we reported 15 years ago;3 but it is the best example they’ve got (despite it not being true).
At least they are honest enough to admit that there are many evolutionary sequences which should exist in the fossil record if gradual evolution were true, and they just aren’t there. That’s why they have to believe that turtles are hopeful monsters.
Here is the rather confusing way a Scientific American contributor explained it.
Who’s on the stem, who’s in the crown? If you know anything about the geological history of turtles, you’ll be aware that a few anatomically archaic Late Triassic and Early Jurassic turtles have been regarded as the oldest representatives of Cryptodira and Pleurodira, the two great turtle groups that exist today. Most notable among these are the Late Triassic Proterochersis (originally described as the oldest known pleurodire) and the Early Jurassic Kayentachelys (originally described as the oldest cryptodire). A Late Triassic pleurodire would mean that the common ancestor of crown turtles was in existence by this time.
But this has been challenged. In a study devoted to phylogenetic analysis of Mesozoic turtles, Joyce (2007) argued that these early turtles are outside the crown group (crown group = the clade that contains living species and all descendants of their most recent common ancestor), and that crown turtles did not, in fact, evolve until considerably later (the Late Jurassic). Joyce (2007) and, later, other authors (Sterli et al. 2013) went further, proposing that a large number of additional taxa – among them the remarkable meiolaniids of the Cretaceous and Cenozoic, the fabled Kallokibotion of the Late Cretaceous of Romania and the diverse and abundant baenids of the Cretaceous and Paleogene – were stem-turtles too, not archaic cryptodires as long thought. This reallocation of taxa and revised view of turtle history has been accepted by some turtle specialists but not by others, and these two schools of thought currently appear to be at an impasse.
You might be thinking that none of this matters much, and perhaps you’d be right. 4
In one sense, none of this matters at all. All this speculation about how turtles evolved is pointless because the theory of evolution is just a fairy tale, so it doesn’t really matter how you tell it.
On the other hand, it does matter because it highlights the non-scientific nature of the theory of evolution.
The “model proposed by Joyce” is nothing more than an opinion. That opinion biases how one analyzes data, which affects the conclusions reached.
The reason why different models have been proposed is because the data doesn’t really support any model. There is no evidence of gradual evolution in the fossil record, and no plausible explanation or confirmation of evolutionary saltation.
These various models of turtle evolution are just stories told to get government grants, or to sell books.
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2 “Book Review – Turtles as Hopeful Monsters”, https://blog.nhbs.com/title-information/reviews/book-review-turtles-hopeful-monsters/
3 Disclosure, February, 2002, “Horses and Peppered Moths”, http://scienceagainstevolution.info/v6i5f.htm
4 Darren Naish, August 17, 2017, “Letters From the World of Turtle Evolution”, https://blogs.scientificamerican.com/tetrapod-zoology/letters-from-the-world-of-turtle-evolution/