Donald R. Prothero’s “The Story of Life in 25 Fossils” and the evidence for evolution

Credit: Wikimedia Commons- H. Raab (User: Vesta)

I come from a background that was young earth creationist and have gone on a very lengthy journey that went from young earth creationist to theistic evolutionist to old earth creationist (a long time) to tentative endorsement of Intelligent Design and back to theistic evolution/evolutionary creation. In other words, I’ve thought about this a lot. I have several shelves dedicated to books on the topic, and have cycled my share of them through the shelf as well, updating to the latest or most interesting ones as I discovered them. I’m very thankful that I had friends who, despite being creationists themselves, spoke kindly to me as I began to explore this issue and were able to help me out of my crisis of faith when I became convinced geological history could not be contained in 6-10,000 years. So yes, I remain a Christian, and yes, I am convinced of the truth of evolution. One question I get asked about this “Why? Why believe that evolution is true?” I present here one of the several reasons I changed my mind. I write this with the caveat that I am not an expert in this field and am presenting the evidence as well as I can.

Interpreting Fossil Evidence

One of the most famous photographs of a fossil is that of archaeopteryx. Its strange shape captures the eye. The way its neck is twisted in death. The pronounced, clawed “fingers” coming from wings. Wings? Yes, there they are, writ plain in stone: feathers on this clearly dinosuar-looking specimen. Now, some will immediately scoff. After all, haven’t some scientists said that archaeopteryx is not a transitional form between birds and dinosaurs? Yes, so far as I can tell, some have said that. But what such a reaction does not account for is that what this means is that some scientists are saying that archaeopteryx cannot be established as the ancestor of living birds today. That does not mean that it is not a transitional form. Indeed, looking at such a fossil, one can’t help but see it as a pretty powerful example of a bird-dinosaur. I use this example because it illustrates a few of the errors I myself fell into. The first is overconfidence. It was pretty remarkable for me to think that just because I read that some scientists disagree with one interpretation of the significance of a fossil, I could reject the significance of it altogether. Second, it shows the kind of whack-a-mole strategy I and others use(d) to interact with evidence for evolution. Rather than viewing the evidence as a totality, it was much easier to dissect individual pieces and try to poke holes in specific, single strands of evidence. Third, and perhaps most importantly, it illustrates the error of thinking that if a series of steps A through Z cannot be known to the extent that every letter is put in exacting order, the series itself is rejected. That is, not being able to say with certainty whether D came before or after E along that chain of evidences does not entail that there is no chain. It simply means we may have uncertainty regarding specific steps along the chain.

Specific Fossil Evidence

Enter Prothero, and others. Donald R. Prothero’s book, The Story of Life in 25 Fossils is a powerful, accessible account of how 25 famous fossils illustrate the truth of evolution throughout life’s history. Each of the 25 stories of fossils, their discoveries, and how they can be shown to be in a web of life is fascinating. Here, I’d like to highlight a few that I think serve to illustrate the powerful evidence for evolution.

Archaeopteryx 

Yeah, that’s right. I’m going back to the one I already mentioned. Why? Because Archaeopteryx is really just the first of the many, many examples we have of feathered fossils that help illustrate the steps along the way from dinosaur to bird. It would be one thing if that famous bird-reptile were all we had to go on, but the fact is that there are many, many other fossils that have been discovered. Archaeopteryx is just the most famous. But when you start to put these fossils alongside each toher, and line them up with a skeleton of a modern pigeon, for example, you can observe the clear anatomical features that each illustrates. It’s not just feathers, but the elongated fingers of the archaeopteryx and the way they appear to be just a longer version of those same features on dinosaurs like orintholestes. But these are not the only examples, Sinosauropteryx is another example of a feathered dinosaur that exhibits features that would later be found on birds. Yutyrannus has direct evidence of feathers, but also has indirect evidence for a tongue like that of modern birds. The stunning images of preserved Confuciusornis can’t help but call to mind crows and other bids, despite it still having dinosaur-like forelimbs. The more and more fossils are found, and modern technology can analyze their feathers and compare them to modern birds, demonstrating several stages to get to the feathers birds use to fly in the skies of our own time.

Indeed, looking at modern birds, one sees the scales on their feet. Look at the talons of raptors today, and one can see the evidence of transition on their feet, the scales that cover them and their shape, and then look at fossilized dinosaur skin or the way theropod dinosaur feet are shaped. I once wrote this off as God using a good design multiple times, but that again illustrates the error of trying to explain individual features rather than looking at a holistic picture. Looking at the whole, and observing the many fossils that have been found since the famous archaeopteryx, one cannot help but see the evidence for a series of life forms that transitioned from dinosaur to bird.

Odontochelys

Some of the most striking evidence for evolution requires a literal digging (har har). This kind of evidence isn’t flashy; it isn’t the kind of fossil photograph you’ll see on the news, but it is significant, convincing evidence nonetheless. Think about the turtle. It’s not that exciting, but there are a lot of (slow-)moving parts that have to get pieced together to make the turtle work. A retractable neck, a shell for protection, a way to eat–these are just some of them. But how did turtles get a shell? It’s the kind of absurdist story creationists put forward to try to discredit evolution. One day, a reptile of some sort lays an egg, and out pops a creature with a shell! Impossible! Yes, of course it is. But that doesn’t mean a number of gradual steps could not have gotten from shell-less creature to one with a shell. And that is the kind of evidence we do have.

Odontochelys is not going to win beauty pageants. It looks like roadkill in fossil form, and artist depictions don’t make it look that much better. But when you look at the bone structure you can see it there as plain as day: a prototype shell, but one that only covers the bottom of the creature. It is something like a halfway point to the turtle. Prothero notes that the creature provides the answer to the question “How could turtles have evolved from no shell to a full shell?” (148). The way this happened, scientists think, is through the expansion of ribs on the back of the proto-turtle into a shell to protect from predators. Odontochelys essentially shows this in process and mostly settled the debate over where the shell came from. Indeed, tying it together with Eunotosaurus, one can see the same back ribs in transition at an earlier stage. Another fascinating feature of Odo (sorry, had to sneak a Star Trek reference in somewhere) is that it has teeth in the beak still, showing both features of a turtle (beak) and earlier creatures (teeth). It truly is a remarkable discovery because it appears to be a real transitional halfway point between earlier reptiles and turtles. Just think about it abstractly. Strip away the knee-jerk reaction to try to explain away fossils and really look at it. It would be hard to ask for a better transitional fossil.

Ambulocetus

The evolution of whales from walking relatives is one that I fought against intellectually for a while. It just seemed like an absurdist story: life emerged from the water, dominated the land, and then decides to crawl back into the oceans? Ridiculous! I spent quite a while looking over creationist literature on this and laughing about the silliness of evolutionary explanations. Then, I decided to read “the other side” because I wanted to write about it myself. I was astonished. The pictures of a walking mammal gradually lengthening a snout, shifting to flippers, elongating the tail, etc. weren’t just conjured out of nothing. They were based on actual fossil evidence scientists have found. And that fossil evidence shows significant evidence for the lineage of whales over time.

Ambulocetus is special because it shows the increase in size from the earlier specimens, the long toothy snout similar to early whales, ears more suited to being in the water, long fingers and toes that possibly had webbing, and a spine that was able to undulate up and down similar to some whales (275-277). These features place it fairly well between earlier walking creatures and later swimming creatures. It shows features of both, and is a kind of halfway point between the walking mammals earlier and the later whales. Discoveries like Rodhocetus helped solidify that evidence, showing the elongation of the snout that continued towards what whales had/have as well as a tail that was better suited to helping steer in the water. It is just the kind of step-by-step process that is often challenged to be presented in creationist literature, but it has been found! Again, I doubted this sequence very much, in part because I was assured by some creationist literature that such a sequence was purely speculative (with the implication that the fossils didn’t exist) and in part because it just seemed kind of silly (creatures emerged from the water only to return?). But the fossil evidence is quite strong on this lineage and it’s astonishing to see creatures like Gaviocetus that continue the trend. Creationist literature disparages the fossil evidence due to some aspects of it being inference, but the fossils that have been found demonstrate the features in a convincing line of change from walking to swimming. It’s a fascinating look at the evidence for evolution.

Now What?

Okay, so I affirm evolution and I have presented some evidence I think is convincing. But why am I a Christian still? There are many, many answers for that and they’d largely center around theological reasons, but speaking specifically on this issue, the fact is that from before evolution was ever a theory through its earliest genesis in intellectual circles and beyond, Christians have struggled with and debated the topic. It is just false to think no Christians immediately embraced evolution, as many did and saw it as evidence for God’s sustaining providence in all things. George Frederick Wright (1838-1921) is one who noted this synergy and argued against those who charged him with affirming deism, for example. Christianity and evolution are not enemies. Each has evidence to support it and reasons to believe it, and together they form a powerful way of understanding the world.

One thought on “Donald R. Prothero’s “The Story of Life in 25 Fossils” and the evidence for evolution

  1. […] but also numerous amazing examples, like turtles, having “halfway” point type fossils. I wrote about some of these elsewhere. Again, do we have every one of the presumably hundreds of species preserved to get from point […]

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