Argument from Design BUSTED!

The Argument from Design (the Teleological Argument) says that life looks designed. For example, we marvel at the cell’s tiny protein-building machines. Some bacteria have flagella that propel them at twice the proportionate speed (body lengths per second) of a running cheetah. A single microscopic cell is able to divide and differentiate into a full-grown oak or zebra or human.

William Paley famously said over two centuries ago, “The marks of design are too strong to be gotten over. Design must have had a designer. That designer must have been a person. That person is God.”

We must avoid the temptation, however, to imagine that complexity implies design. Elegance might, but mere complexity (especially unnecessary or sloppy complexity) gives little support for design. The cell, marvelously complicated though it is, may be more a Rube Goldberg machine than the elegant and sophisticated product of an omniscient designer.

What Does the Argument from Design Mean?

The Argument from Design imagines that we see the hand of a designer. All right, then: what would that look like? The only designers we know are human designers. (Let’s ignore the possibility of animal designers.) The Argument from Design then says: life looks like it would if made by a human designer with sufficient capability.

Consider the design criteria human designers use. A bridge might be designed for unusually high loads, so strength would be most important in this design. Or maybe speed of assembly is an important criterion. Maybe the bridge is remote, so it should have a long life or be maintenance free. Maybe it must use local materials. Maybe it’s in the middle of a town or city, so beauty is important.

These goals—strength, speed of assembly, durability, constraints on materials, and beauty—are some of the criteria designers might follow. But a criterion you never find in a human design is that the finished product should have added junk.

You may not like the Art Deco decorations at the top of the Chrysler building, but they were put there deliberately to follow the criterion of beauty. You may find a design that was poorly built or left unfinished, but that was never a goal of the designer. Useless junk is never in a design on purpose.

Contrast this with the crap that DNA has in it (as discussed in a recent post). Human DNA has a broken vitamin C gene in every cell as well as 20,000 other nonworking pseudogenes. Eight percent of our genome is composed of nonworking junk injected by viruses over millions of years. Atavisms (archaic genes that are accidentally switched on, like human tails) and vestigial structures (such as eyes in cave fish) are flashbacks to body features from species in the distant past. Onions have much more DNA than humans do, as do lots of other plants and animals, so either they need many times more DNA than humans or their genome has a lot of junk.

The Christian Response

The first argument Creationists often make is that made by Jonathan Wells in The Myth of Junk DNA. He argues that we keep finding new uses for fragments of human DNA that we previously thought were nonfunctional. Okay, so the fraction that we think is useless will decrease. Will it go to zero? Will we find that onions really do need five times more DNA than humans? There is no reason to imagine this, and junk DNA lives on.

The Design Argument says that life looks as if an omnipotent human designed it. It’s clearly wrong. DNA, the marvelous molecule that apologists point to as evidence of a designer, looks unlike anything that any sober designer would make. DNA alone is enough to sink the Design Argument.

Note that you can’t just say that life is impressive or amazing or marvelous or complex. True or not, that would be irrelevant. These attributes could apply to lots of things—crystals are complex and snowflakes are amazing and rainbows are marvelous, but they weren’t created by a designer. You must show how life follows design rules that a designer (and the only examples of designers that we have are human ones) would have followed.

Christian response #2: I guess that just shows that God has a broad palette. Tidy DNA or sloppy DNA, clearly these organisms work. I’m not complaining.

Yes, they work, but don’t make the Designer Argument to explain them. Richard Dawkins observed that Paley was doing good work, given that he was writing fifty years before Darwin’s On the Origin of Species, and that he would likely have been on board with evolution if given the chance.

3. Intelligent Design proponent Stephen Meyer said, “DNA functions like a software program. We know from experience that software comes from programmers.”

Not really. Some software comes from programmers, and some comes from random processes. Genetic programming evolves software like evolution evolves life forms. Competing versions of a program are randomly mutated and then selected for fitness, all within a computer. The winning programs in such an evolutionary process are the sloppiest software imaginable—not at all what a human would design, but reminiscent of DNA.

Evolution’s random mutation + selection can make lots of things. Here’s a simulation of random polygons added to an image selected to look like Mona Lisa. Here’s an evolution of random parts selected to make a car.

4. But DNA is information! Show me an example of information not coming from intelligence. Show me information not coming from a mind.

Show me an example of intelligence or a mind that’s not natural. Science recognizes no supernatural examples of anything, let alone intelligence and mind. We’re back to square 1, with supernatural claims without good reason to believe them.

But to your point, the examples of evolutionary software given earlier show information coming from a non-intelligent process. If you say that the software was intelligently designed, that’s true, so ignore the software. Make this a thought experiment. Imagine random polygons being added with a selection process that defines “fitness” as “looks like the Mona Lisa.” The software simply makes the thought experiment tangible.

5. Suppose I have dents in my car. Obviously, they’re imperfections of the design, but they weren’t put there by the designer. Just ignore them. Similarly, imperfections in DNA are no criticism of the Designer.

If your blue 2003 Honda Civic has dents, we can find a blue 2003 Civic without those dents to use as our standard of perfection. What’s the equivalent for human DNA? There is no perfect example to imagine that our DNA descended from.

There simply is no human DNA without pseudogenes, and the fact that some protozoa have 400 times more DNA than humans remains.

Where’s the evidence that going back in time, you find perfect DNA? Was human DNA perfect 3000 years ago when the stories that became the Bible began to be collected? Was it perfect in our last common ancestor with chimpanzees six million years ago? Was it perfect in the animals that came out of the Cambrian Explosion more than 500 million years ago? Science breathlessly awaits your evidence.

6. God’s design was perfect initially, but the Fall—that whole snake-and-apple thing—caused the imperfections in life that we see today.

Why would a human failing cause sloppiness in non­-human DNA? Anyway, this is irrelevant. It simply accepts that life doesn’t look designed, and the Design Argument fails. There is no perfect human DNA except in the imagination of this apologist.

7. Ah, but God is inscrutable. We don’t understand his ways. He designs in his own way that might seem bizarre to us.

If God’s handiwork is so bizarre that it doesn’t look like the work of any designer, then don’t make the Design Argument!

8. But you haven’t proven that God doesn’t exist.

Sure, God might exist. God might use evolution to carry out his plan. God might be a clockmaker who touched off the Big Bang and walked away. The focus of this post was simply to show the flaws in the Design Argument.

Does God exist? Maybe, but the Design Argument, which says that we see in life the attributes of design, is no tool by which to make the case.

There’s one thing the Bible makes clear: 
The biblical God is a sloppy manufacturer. 
He’s not good at design, he’s not good at execution. 
He’d be out of business if there was any competition.
— Contact by Carl Sagan

(This is an update of a post that originally appeared 1/21/13.)

The Design Hypothesis, DNA, and Dysteleology

DNA DesignDysteleology is the idea that life or nature does not show compelling evidence of design, in contrast to the Christian perception of purpose or design (teleology). The marvelous complexity in DNA is often cited by Creationists as the best evidence for their position. The facts tell a different story, and DNA makes clear that life looks more haphazard than designed.

Let’s consider four aspects of DNA that make it look not designed.

1. DNA Size

Human DNA has 3.42 billion base pairs. You might imagine that humans need the most DNA since the gods in Genesis said, “Let us make man in our image,” but we’re not even at the top of the list of mammals. Cows, mice, and bats have more.

And mammals don’t have as much DNA as other animals. One kind of salamander has 126 billion base pairs in its DNA. Does it really need 37 times more DNA than humans? Or could there be a lot of (dare I say it?) “junk” in that DNA?

We find much variability in fish DNA. The longest DNA (for the marbled lungfish) is almost 400 times the size of the smallest (the green puffer fish).

There are grasshoppers, beetles, ticks, worms, and snails that have more DNA than we do. There are plants that have more than we do—the onion, for example, has five times more. The record holder, with 400 times more DNA than humans, is a protozoa.

The wide variability in DNA size is shown in this chart:

c values

This is a logarithmic chart of the weight, or c-value (a proxy for DNA length), of the DNA of many categories of animals. Humans are in the “mammals” category at the top.

Maybe DNA is all useful and length is proportionate to the complexity of the organism. Maybe many animals are just more complex than we are, but then how can Man be God’s greatest creation? The alternative explanation is that there’s a lot of waste in DNA, but that rejects the idea of a designer. Neither is a good option for the Creationist.

2. Pseudogenes

All mammals synthesize vitamin C. They produce it internally and don’t have to eat it. All mammals, that is, except a handful, such as humans. We get scurvy if we go too long without eating vitamin C.

When you look in human DNA, you find a pseudogene (a broken gene) for vitamin C production, right where most other mammals have a functioning gene. Apparently, ancestors of humans and a few other primates once ate a diet rich in vitamin C so that a random mutation that broke the gene didn’t convey a selective disadvantage. The pseudogene spread through the population, and here we are, with every cell carrying a useless gene.

We find another example of a useful gene that didn’t have enough survival value to be selected for in the Antarctic icefish, which has no hemoglobin (the oxygen transport molecule) because of the oxygen-rich Antarctic water.

Smell is an area where humans have many pseudogenes. Of our roughly 100 odorant receptor genes, most don’t work. Many other mammals have working versions of these pseudogenes. At the other end of the scale is the dolphin, which has no working odorant receptor genes. They’re all pseudogenes.

Overall, human DNA has 20,000 pseudogenes—again, not evidence of the hand of a designer.

3. Endogenous Retroviruses

A virus can’t reproduce by itself and must force a cell to do it, which causes disease. Where it gets weird is when the virus infects a germ cell (egg or sperm). Then the viral DNA, inactivated by mutation, is passed on to succeeding generations. Becoming part of the genome is the “endogenous” part.

DNA keeps a record of these invasions. Human DNA has thousands of endogenous retroviruses, mostly just fragments, which compose up to 8% of our genome. One, the 5-million-year-old “Phoenix virus,” has been reconstructed from human DNA.

4. Atavisms and Vestigial Structures

Birds don’t have teeth, but their theropod dinosaur ancestors did. In fact, the ancient genes for teeth are still present in bird DNA. Scientists have been able to tweak chicken DNA to turn on these genes and get chickens with conical, dinosaur-like teeth.

When archaic genes are switched on in nature, those are called atavisms. Snakes can have legs, dolphins can have a hind pair of limbs, and humans can have tails.

Vestigial structures are those that have lost most or all of their ancestral function. Note that they’re not necessarily useless (Creationists delight in pointing out the value in the human appendix or tailbone); they’re just not used for what they were originally used for. For example, ostrich wings are vestigial because they can’t be used to fly (that’s what wings do).

Other examples are eyes in blind mole rats or cave fish, the pelvis (for nonexistent legs) in the baleen whale, and goose bumps (to raise nonexistent fur) in humans.

None of this proves that God doesn’t exist. What it does make clear is the difference between complexity, which we see in DNA, and evidence of a careful and skillful designer, which we don’t.

Yes, evolution by descent from a common ancestor is clearly true. 
If there was any lingering doubt about the evidence from the fossil record, 
the study of DNA provides the strongest possible proof 
of our relatedness to all other living things.
— Francis Collins, evangelical Christian and head of NIH

(This is an update of a post that originally appeared 1/16/13.)

Photo credit: U.S. National Library of Medicine

10 Tips for Dealing with Creationists

creationism evolutionI hang out with Creationists occasionally and have seen many of the arguments they make. I’d like to tell you what I’ve found.

This isn’t a rebuttal against Creationist arguments (perhaps in a future post). Rather, I’d like to sensitize you to general errors that they make. Consider this a list of cautions when evaluating a Creationist presentation. (I respond to a Chick tract full of Creationist errors here.)

1. Check the speakers’ credentials. Almost no one who speaks as a Creationist or Intelligent Design proponent has credentials in the field he’s criticizing. I’m simply asking for speakers with doctorates in the field plus work credentials. That is, a biologist speaking about biology, a geologist about geology, a cosmologist about cosmology, and so on. There are hundreds of thousands of scientists. That this seems to be a lot to ask says a lot about Creationism and related dogmas.

There are journalists without scientific degrees who popularize science, but they follow the consensus. They don’t try to apply their own agenda to overturn it. Creationists attempting to overturn the biological consensus from outside biology—that’s something different.

2. Check dates of quotes or criticisms. Words can’t express how uninterested I am in what Darwin wrote or thought or did. Almost every Darwin quote that I’ve seen used by the Creationist/ID side has been taken out of context. Anyway, Darwin’s writings are not binding on evolutionary biologists today.

And don’t get me started about Darwin’s personal life—whether Darwin ate babies with barbeque sauce or plain (actually, he lived a pretty laudable life) says nothing about the question at hand: whether evolution is the best explanation for why life is the way it is.

3. Focus on the right bin. A popular complaint is to say that evolution led to eugenics, or that the teaching of evolution in public school correlates to the tragic downward spiral that society has made in the past 50 years, and it wasn’t like this when I grew up, and don’t get me started about the kids these days, and blah, blah, blah.

Evolution is science. Eugenics is policy. The scientists give society the best approximation of the truth, and the politicians decide what to do with this information. Don’t blame science for policy.

4. Watch for Hitler entering the conversation. Godwin’s Law states: “As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1.” Whether Hitler embraced evolution or not (unlikely, since Darwin was on the Nazi list of banned books—more here), what Hitler liked has no bearing on the accuracy of evolution.

5. Beware lists of Science’s errors. I’m thinking of lists such as the greatest hits of evolution’s mistakes—Piltdown Man, Nebraska Man, “Flipperpithecus,” and so on. Or theories that have been discarded—ether, phlogiston, geocentrism, the steady-state universe.

Yeah, science makes mistakes. Get over it. And what process discovered the errors? No, not Christianity or Creationism or divine revelation, but science!

Science clearly delivers pretty good approximations of the truth. For one glaring example, consider the science underpinning all the technology by which I communicate to you right now.

6. Watch for lots of quotes. Lots of quotes by scientists (often with missing or old dates) is another bad sign. Quotes simply invite counter-quotes, where I try to trump your science-y quote with one of my own, back and forth. For discussions between non-scientists, it’s better to stick with the consensus, which needs a reference but not a quote.

7. Expect “We’ve seen that evolution is wrong, so Creationism must be right!” This is simply a false dichotomy. Evolution might be wrong (though the evidence is so overwhelming that this is hard to imagine), but even if we discarded it, that wouldn’t leave Creationism the victor.

Did some Creator put life on earth? Wow—that’s an enormous claim. Provide the evidence.

A variation of this is a confident and enthusiastic assurance that the theory of evolution is in crisis, that all the rats are jumping ship, that the latest research shows its failures, that leading biologists reject it, and so on. In lectures, articles, books, or in-person discussions, I must’ve seen this a dozen times. The claim is wrong.

8. Beware the “Gish Gallop.” Duane Gish pioneered this underhanded debate tactic. When interviewed with a biologist, he would say something like, “Well, what about X? And Y and Z? Evolution can’t explain these things.” His biologist opponent probably had explanations for these puzzles and so began a tedious (for the audience) explanation of why these are nicely handled by evolution. But when the biologist stops for a breath, Gish is back, piling on more examples. If your goal is winning the argument rather than engaging with the truth, these kinds of games can make an effective approach.

What I find especially annoying is hearing an issue get thoroughly rebutted but then reused without change by the Creationist in the very next encounter. How many times has a biologist destroyed Ray Comfort’s “Where’s the crocoduck?” argument? And yet it pops back up like we’re playing Whac-a-Mole. Does he just value effectiveness over integrity?

9. Beware lying. Okay, that sounds harsh, but I don’t know what else to make of nonsensical claims from people who should know better.

In 2007, I attended a lecture by someone from the Institute for Creation Research, a young-earth Creationist organization. This lecture was remarkable because the topic was geology, and the speaker actually had a doctorate in geology. He described taking rock samples from an amphibolite layer in the Grand Canyon and getting various radioisotope dating results. Though the rocks were all from the same layer, the date estimates were all over the map. His unsurprising conclusion: this dating technique is flawed, and the Grand Canyon layers were laid down by Noah’s flood, thousands of years ago, not hundreds of millions.

Only after the lecture, after I’d done some research, did I learn that amphibolite is a metamorphic rock, and radioisotope dating is typically reliable only for dating igneous rocks. That the geologist didn’t bring up this point makes me reject his entire premise as unreliable.

10. Beware “Science backtracks all the time!” Science does find errors and correct itself, but don’t imagine that the next correction to evolution is as likely to be a small tweak as the overturning of the entire theory. Once a field is well understood, changes obey a power law (we see this with the magnitude of earthquakes, the frequency of word use, or the size of cities and towns). For every big earthquake we see thousands of tiny ones, and for every huge correction in a theory we see many small tweaks. The overturning of a well-established theory is very unlikely.

Isaac Asimov addressed this: “When people thought the Earth was flat, they were wrong. When people thought the Earth was spherical they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together.”

Since Creationists can’t be trusted to evaluate and discuss science, how can we trust their interpretation of the Bible, which is far more ambiguous?

Debating with a creationist is like playing chess with a pigeon. 
It jumps on the board, knocks all the pieces off, craps on the table, 
and flies off to its flock to claim victory.
— Anonymous

(This is an update of a post that originally appeared 11/19/12.)

Image credit: Rennett Stowe, flickr, CC

Making Sense of “Survival of the Fittest”

Survival of the FittestThe term survival of the fittest” did not initially come from Charles Darwin’s Origin of Species, though later editions did use it. It was first coined by Herbert Spencer after he read Origin.

While a convenient phrase, it can be confusing. “Fit” in biological terms doesn’t mean what we commonly think (strong, quick, or agile, for example) but refers to how well adapted an organism is for an environment. Think of it as puzzle-piece fit, not athlete fit. Shortly after Origin, one commenter recommended “fittedness” instead of “fitness,” which might make a clearer mental image.

Creationists sometimes use the phrase to mean that might makes right or that the most savage or ruthless or selfish will survive. On the contrary, rather than might makes right, cooperation can be the better approach. This is the case for social animals like humans and other great apes. And even if evolution has some bloodthirsty aspects to it, how does that change whether it’s an accurate theory or not?

NewScientist magazine says:

Although the phrase conjures up an image of a violent struggle for survival, in reality the word “fittest” seldom means the strongest or the most aggressive. On the contrary, it can mean anything from the best camouflaged or the most fecund to the cleverest or the most cooperative. Forget Rambo, think Einstein or Gandhi.

What we see in the wild is not every animal for itself. Cooperation is an incredibly successful survival strategy. Indeed it has been the basis of all the most dramatic steps in the history of life. Complex cells evolved from cooperating simple cells. Multicellular organisms are made up of cooperating complex cells. Superorganisms such as bee or ant colonies consist of cooperating individuals.

Note also that evolution is descriptive, not prescriptive; it simply says what is the case and doesn’t provide moral advice. “I’ll model my morality on evolution” makes as much sense as “I’ll model my morality on the fact that arsenic kills people.”

Creationists sometimes twist Darwin’s The Descent of Man to argue that he favored eugenics. Darwin’s damning paragraph said, in part, “hardly anyone is so ignorant as to allow his worst animals to breed.” In the first place, whether Darwin ate babies plain or with barbeque sauce says nothing about whether evolution is accurate or not. In the second place, the very next paragraph clarifies Darwin’s position about denying aid to the helpless.

Nor could we check our sympathy, even at the urging of hard reason, without deterioration in the noblest part of our nature.

“Survival of the fittest” is a handy description of natural selection as long as all parties understand what it means.

Blogs are the opium dens of the 21st century.
— commenter Asmondius

(This is an update of a post that originally appeared 4/21/12.)

Photo credit: EvolveFish

Darwin Day Response to Creationist Chick Tract

Darwin Day CreationismI recently saw the trailer for the upcoming “God’s Not Dead” movie. A Christian college student discovers that his philosophy class is taught by a dictatorial atheist who demands that all students declare that God is dead. He refuses and is forced into public debates with his professor.

Until I’m able to review that movie, and in honor of Darwin Day, I’d like to critique a Chick tract that closely parallels that plot. These arguments are pretty weak, but with the Ham on Nye debate last week, it’s clear that weak evolution-denial arguments are popular in some circles.

Chick tracts are tiny comics handed out to spread the gospel. “Big Daddy?” opens in a biology classroom with a portrait of an ape titled “Our Father.” (As the story progresses, I’ll give my rebuttals in parentheses. Read along, and see if your favorite Creationist claim makes an appearance.)

The professor asks how many of the students believe in evolution. All but one student is on board, and the professor is furious at the holdout. He’s about to expel him from the class but thinks better of it. Destroying the Christian argument will make a good demonstration for the class.

You can’t mention the Bible in school

The student begins by using the word “Bible,” and the professor declares that that is illegal. Here we have the first of many footnotes referencing Kent “Dr. Dino” Hovind. While our nutty professor is wrong that mentioning the Bible is illegal, the footnote is wrong when it says, “it has never been against the law to teach the Bible or creation in public schools.” Teaching the Bible in a comparative religions class is fine, but it’s not legal to evangelize from the Bible or teach Christian creation as science.

Hovind is a poor authority. His doctorate is from a diploma mill, and he’s now serving a ten-year sentence in prison for federal tax evasion.

Does science prove anything?

The professor declares that science proves evolution. (No—mathematics proves things, not science. Science is always provisional. I would say: evolution is the scientific consensus.) He points to carbon-14. (A biologist would likelier point to the entire field of radioisotope dating, not just C-14, which can take us back only about 40,000 years.)

The many flavors of “evolution”

The Christian student argues that there are six kinds of evolution—cosmic evolution, chemical evolution, stellar evolution, organic evolution, macroevolution, and microevolution. Don’t worry about the distinction—it’s not much clearer in the comic. Creationists sometimes argue that “evolution” is ambiguous to justify their use of the word “Darwinism,” but I’ll stick with the term used by biologists.

The student says that all but microevolution are believed by faith. (Science is accepted because of evidence, not faith.)

Piltdown Man was a hoax

Next, he attacks fossil dating by stating that Richard Leakey found a modern skull under 212-million-year-old rock. (Nope. That skull was an early hominid dated to 1.9 million years.) Our precocious student then declares that Lucy was just a chimpanzee, not an early hominid. (I saw Lucy when it toured the U.S. in 2009. Our student is wrong again—the consensus is clear that Lucy is an Australopithecus.)

Next, we see a chart listing various hominid fossils, with comments dismissing each of them. But no biologist would include Piltdown Man (a hoax) and Nebraska Man (an error) on such a list. Other fossils are dismissed as irrelevant, but again, that’s Dr. Dino talking.

Note also that hominid fossils alone provide little evidence for evolution. Only given the overwhelming evidence for evolution from DNA evidence and the enormous variety of other fossils can we make sense of the hominid evidence.

Fossil dating uses circular reasoning.

Oh dear—Professor Frantic is losing this debate. He changes the subject to the old dates of fossils, and the student charges him with circular reasoning—we know that a layer is old because it has trilobites in it, but we know that trilobites are old because of the age of the surrounding layers. (Which is nonsense. Radioisotope dating is reliable only for igneous rock like basalt or granite. Fossils in a sedimentary layer can be dated by nearby layers of basalt laid down as lava, for example. If there isn’t any convenient igneous layer, new fossils can be dated by using other, known fossils if those fossils were reliably dated at some other site.)

The quick-witted student next brings up what Creationists call polystrate fossils—fossilized trees that intrude through many layers. If layers deposit very slowly, is a dead tree going to sit there, unchanging, for millions of years while the layers of sediment slowly accumulate around it? (The error, of course, is that layers are sometimes laid down very quickly. For example, land can subside during an earthquake. When that land is next to the ocean, many feet of sand can be deposited within hours.)

Embryology errors

The professor tries again and says that human embryos have gills, which proves that they evolved from fish. The student points out that Haeckel’s embryos are discredited. (Haeckel made a mistake—get over it.)

But here’s something I don’t get. I realize that Haeckel’s “ontogeny recapitulates phylogeny” has been discarded, but why do human embryos have gill-like features and then repurpose them? Why do they get a tail but then reabsorb it? Isn’t repurposing rather than building something in its final form clues to our earlier ancestors? Point me to something on this if you can.

Vestigiality?

The professor points to the human tail bone and the pelvis in some whales as vestigial structures. Mr. Smart Ass replies that both bones are useful because they anchor muscles and so aren’t vestigial. (Wrong again. “Vestigial” refers to something no longer used for its ancestral function. Wings on an ostrich are vestigial, not because they’re useless [they’re not] but because they aren’t used for flying. Similarly, the whale’s pelvis isn’t used for providing support for legs, which is what pelvises do.)

The student says, “Even if there were ‘vestigial’ organs, isn’t losing something the opposite of evolution?” (Dude—read a textbook on evolution! Animals evolve by becoming better suited to their environment. We might call that a loss [loss of eyesight in a cave fish or loss of walking for a sea mammal] but that perspective is pointless. By being selected by evolution, these animals have become fitter.)

And we have a winner!

After a bizarre turn where the student rejects the idea of gluons, our bedraggled atheist hero is ready to hear from the Bible. A beaten man at the end, he takes his ape portrait and resigns. The Christian victor wraps it up for his fellow students: evolution is a lie and Jesus saves.

Back in the real world

This is embarrassingly bad science. Creationists, study up on evolution before you try to attack it.

Believers, think about all the things you would do if you were God.
Then contemplate the fact that you worship a God who hasn’t.
— Tiger C. Lewis (paraphrased)

Photo credit: Chick Publications

Forget the Cambrian Explosion—Here’s a SERIOUS Biodiversity Event

Darwin's Doubt Stephen MeyerA few months ago, I attended a lecture by Stephen Meyer of the Discovery Institute about his new book, Darwin’s Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design.

He explains “Darwin’s doubt” in the Amazon summary:

When Charles Darwin finished The Origin of Species, he thought that he had explained every clue, but one. Though his theory could explain many facts, Darwin knew that there was a significant event in the history of life that his theory did not explain. During this event, the “Cambrian explosion,” many animals suddenly appeared in the fossil record without apparent ancestors in earlier layers of rock.

The Cambrian explosion was the appearance of all but one of the 35 present animal phyla (body plans) in the first 20 million years of the Cambrian period.

What did Darwin say?

In On the Origin of Species, Darwin wrote:

If [evolution is] true, it is indisputable that before the lowest Cambrian stratum was deposited long periods elapsed, as long as, or probably far longer than, the whole interval from the Cambrian age to the present day; and that during these vast periods the world swarmed with living creatures. Here we encounter a formidable objection; for it seems doubtful whether the earth, in a fit state for the habitation of living creatures, has lasted long enough.

Darwin then notes that the best evidence available to him gives evolution 100–200 million years since the consolidation of the earth’s crust. In fact, today’s estimate is 4 billion years.

Would Darwin have still found a “formidable objection” if he had known that the earth was actually 20 to 40 times older than he thought? Perhaps Meyer is fairer in his book, but in the lecture, he did nothing to clarify the incorrect data that underlay Darwin’s conclusions.

Who cares?

More to the point, no biologist cares what Darwin thought.

Contrast Darwin with Aristotle. Europe even through the Renaissance compared new developments with Aristotle to see if the great philosopher would have agreed. From 2000 years in the past, Aristotle could frown on revolutionary new ideas. Bertrand Russell said, “almost every serious intellectual advance has had to begin with an attack on some Aristotelian doctrine.”

But no biologist today cares if Darwin would approve of a new idea or not. Darwin did remarkable things for his time, but Darwin is relevant in the field History of Science, not Biology. Evolution deniers like Meyer point out where Darwin was wrong, but this is useful only in mesmerizing the public.

Is the Cambrian explosion that remarkable?

The Cambrian explosion might have been the result of a perfect storm of factors that opened the field to new innovative body plans: predators accelerated the evolution of hard body parts, a global ice age had just ended, the Hox genes that control body plans may have developed at this time, and atmospheric oxygen may have been rising. We might also have underestimated the progress in the Precambrian because those animals were tiny or soft and didn’t leave much of a fossil record.

Let’s also be clear how limited the Cambrian explosion was. It’s a quick expansion in the body plans of animals. That’s it. While it happened quickly, it still took 20 million years, and there was little filling out of these phyla with individual species. There were no land animals, and our ancestors in the phylum Chordata would’ve been no more than primitive eel-like fish at this time (see drawing above). Evolution would slowly push this phylum to produce bony fish (420 million years ago), amphibians (370 mya), reptiles (310 mya), dinosaurs (230 mya), mammals (225 mya), and birds (160 mya).

Plants also developed slowly. We find algae 1200 million years ago, photosynthetic plants 1000 mya, land plants 450 mya, flowering plants 200 mya, and grasses 40 mya. There was no Cambrian explosion here.

Getting back to basics, the remarkable development of the eukaryotic cell (the kind that animals and plants have) from the more primitive prokaryotes such as bacteria happened 2700 mya.

In short, the Cambrian is impressive when we zoom in to just the major divisions in one kingdom, but it ignores most of evolution.

Great Ordovician Biodiversity Event (GOBE)

The Cambrian explosion looks at one feature in the vast expanse of evolution. Another that is at least as remarkable is the Great Ordovician Biodiversity Event. If the Cambrian created the display cases for the phyla, the GOBE filled them with species.

The Ordovician period followed the Cambrian, and it created far more genera (“genuses”) than its predecessor, as the graph below shows.

(The three kinds of fauna listed above aren’t important for this discussion.)

From the perspective of biodiversity, the Cambrian doesn’t look so innovative after all. The article that accompanies the graph states,

This boom was like nothing the world has seen since. The Ordovician is the only time in the history of animal life that huge numbers of new species appeared without a mass extinction to clear the decks beforehand.

Why does Meyer focus on the Cambrian?

Meyer must weave a simple story: evolution expects gradual change, but the Cambrian shows that change was sometimes explosive. Evolution can’t explain this, but Intelligent Design can. And they all lived happily ever after.

But reality looks a lot more complicated than “And God said, ‘let there be many animal phyla,’ and it was so.” The Cambrian explosion is just one part of a big picture. It is separate from the very different explosive growth in the GOBE and the gradual evolution of plants and chordates.

Note also that Intelligent Design advocates didn’t uncover the Cambrian explosion. Biologists did. And it hasn’t convinced them that evolution is wrong. How could it convince me?

See nature through the eyes of science, the only way we ever have learned about it.

Religion is like aspirin.
It’s okay to take a little to make yourself feel better,
but you shouldn’t take too much,
and you shouldn’t force people to take it who don’t want any.
— Daniel Handler (Lemony Snicket)

Photo credit: Wikimedia