The Case for a Creator (34 page)

“To make it even more difficult, a recent study in
Science
magazine found that half the proteins in a simple yeast cell don’t function alone, but they function as complexes of half a dozen proteins or more. Up to fifty proteins are stuck together like cogs in a machine. Of the other fifty percent, most are in complexes of three or four. Very few work as single, Lone Ranger proteins. So this is a huge problem not only in cilia but in other cells too.”

“Some scientists have pointed out that there are examples of other cilia that don’t have some of the parts that you contend are essential,” I said. “One said, ‘In nature, we can find scores of cilia lacking one or more of the components supposedly essential to the function of the apparatus.’ Doesn’t the existence of simpler cilia refute your contention that they are irreducibly complex?”

“If you could point to a series of less complex structures that progress from one to the other in order to create the cilia I’ve described, then, yes, that would refute me. But that isn’t the case,” he said. “What the critics say is that you can take away one of the several microtubules and the cilium would still function. That’s fine. You still need all the basic components—microtubules, nexin, and dynein.

“Let me give you an analogy. Some big mousetraps—actually, they’re rat traps—have double springs to make them stronger. You can take one spring away and it would still work to a degree. In a sense, the second spring is a redundant component. The cilium is the same way; it’s got some redundant components. You can take one of the microtubules away and it will still function, though maybe not as well.

“But evolution does not start with the completed trap or completed cilium and take parts away; it has to build things up from the bottom. And all cilia have the three critical components that I’ve mentioned. There have been experiments where scientists have removed one of the three and the cilium doesn’t work. It’s broken—just like you’d expect it to be, since it’s an irreducibly complex machine.”

THE WORLD’S MOST EFFICIENT MOTOR

As amazing as the cilium is, I was even more fascinated by another biological machine for propelling cells—the bacterial flagellum. “While cilia act like oars to move cells, it was discovered in 1973 that the flagellum performs like a rotary propeller,” Behe explained. “Only bacteria have them.”

“How does it work?” I asked.

“Extremely efficiently,” he said. “Just picture an outboard motor on a boat and you get a pretty good idea of how the flagellum functions, only the flagellum is far more incredible. The flagellum’s propeller is long and whiplike, made out of a protein called
flagellin
. This is attached to a drive shaft by hook protein, which acts as a universal joint, allowing the propeller and drive shaft to rotate freely. Several types of proteins act as bushing material to allow the drive shaft to penetrate the bacterial wall and attach to the rotary motor.”
⁸

“Where does it get its energy?” I asked.

“That’s an interesting phenomenon,” he replied. “Some other biological systems that generate movement, like muscles, use energy that has been stored in what’s called a ‘carrier molecule.’ But the flagellum uses another system—energy generated by a flow of acid through the bacterial membrane. This is a complex process that scientists are still studying and trying to understand. The whole system works really well—the flagellum’s propeller can spin at ten thousand revolutions per minute.”

As a car aficionado, I was staggered by that statistic! A friend had recently given me a ride in his exotic high-performance sports car, and I knew it wasn’t capable of generating that many rpms. Even the notoriously high-revving Honda S2000, with a state-of-the-art, four-cylinder, two-liter, dual-overhead-cam aluminum block engine, featuring four valves per cylinder and variable intake and exhaust valve timing, has a redline of only nine thousand rpms.
⁹

“Not only that,” Behe continued, “but the propeller can stop spinning within a quarter turn and instantly start spinning the other way at ten thousand rpms. Howard Berg of Harvard University called it the most efficient motor in the universe. It’s way beyond anything we can make, especially when you consider its size.”

“How small is it?”

“A flagellum is on the order of a couple of microns. A micron is about 1/20,000 of an inch. Most of its length is the propeller. The motor itself would be maybe 1/100,000ths of an inch. Even with all of our technology, we can’t even begin to create something like this. Sometimes in my lectures I show a drawing of the flagellum from a biochemistry textbook, and people say it looks like something from NASA. If you think about it, we’ve discovered machines inside ourselves. On
Star Trek
they had a creature called the Borg, which has tiny machines inside. Well, it turns out everybody does!”

Drawings of the flagellum are, indeed, very impressive, since they look uncannily like a machine that human beings would construct. I remember a scientist telling me about his father, an accomplished engineer who was highly skeptical about claims of intelligent design. The dad could never understand why his son was so convinced that the world had been designed by an intelligent agent. One day the scientist put a drawing of the bacterial flagellum in front of him. Fascinated, the engineer studied it silently for a while, then looked up and said to his son with a sense of wonder: “Oh, now I get what you’ve been saying.”

“Think of this too,” Behe continued. “Imagine a boat with its motor running. Uh-oh! Nobody’s steering it. It goes out and crashes—
boom!
Well, who’s steering the bacterial cell? It turns out it has sensory systems that feed into the bacteria flagellum and tell it when to turn on and when to turn off, so that it guides it to food, light, or whatever it’s seeking. In a sense, it’s like those smart missiles that have guidance systems to help them find their target, except there’s no explosion at the end!”

“And the flagellum is irreducibly complex?”

“That’s right,” he said. “Genetic studies have shown that between thirty and thirty-five proteins are needed to create a functional flagellum. I haven’t even begun to describe all of its complexities; we don’t even know the roles of all its proteins. But at a minimum you need at least three parts—a paddle, a rotor, and a motor—that are made up of various proteins. Eliminate one of those parts and you don’t get a flagellum that only spins at five thousand rpms; you get a flagellum that simply doesn’t work at all. So it’s irreducibly complex—and a huge stumbling block to Darwinian theory.”

I asked, “Has anyone been able to propose a step-by-step evolutionary explanation of how a gradual process could have yielded a flagellum?”

“In a word—no,” he said with a chuckle. “For most irreducibly complex systems, the best you get is a sort of hand-waving, cartoonish explanation, but certainly nothing that approaches being realistic. Even evolutionary biologist Andrew Pomiankowski admitted: ‘Pick up any biochemistry textbook, and you will find perhaps two or three references to evolution. Turn to one of these and you will be lucky to find anything better than ‘evolution selects the fittest molecules for their biological function.’
¹⁰

“But for the flagellum, there aren’t even any cartoon explanations. The best the Darwinists have been able to muster is to say that the flagellum has components that look like the components of other systems that don’t have as many parts, so maybe somehow this other system had something to do with the flagellum. Nobody knows where this subsystem came from in the first place, or how or why the subsystem may have turned into a flagellum. So, no, there’s no reasoned explanation anyone has been able to offer.”

I tried another approach. “What about Darwinists who say, ‘Maybe it’s merely too early for us to come up with a road map of how these gradual changes developed. Someday we’ll better understand the flagellum, so have patience—in the end, science is going to figure it out.’ ”

Behe leaned back in his chair. “You know, Darwinists always accuse folks in the Intelligent Design movement of making an argument from ignorance. Well, that’s a pure argument from ignorance! They’re saying, ‘We have no idea how this could have happened, but let’s assume evolution somehow did it.’ You’ve heard of ‘God-of-the-gaps’—inserting God when you don’t have another explanation? Well, this is ‘evolution-of-the-gaps.’ Some scientists merely insert evolution when they don’t understand something.

“Look—we may not understand everything about these biological systems, but we do know some things. We do know that these systems have a number of very specifically matched components that do not lend themselves to a gradualistic explanation. We know that intelligence can assemble complex systems, like computers and mousetraps and things like that. The complexity we see is not going to be alleviated by the more we learn; it can only get more complicated. We will only discover more details about the systems.

“Here’s an illustration. Let’s say you have a car in a dark garage. You shine a flashlight on one part of the engine and you see all of its components and its obvious complexity. Shining the flashlight on another part of the motor isn’t going to make the first part go away. It isn’t going to make the problem any simpler; it’s going to make it more complicated. And as we discover more about the flagellum, it won’t negate the complexity we’ve already found. All we’ll have is an even more complicated, more impressive, more interdependent machine—and an even greater challenge to Darwinian theory.”

MOLECULAR TRUCKS AND HIGHWAYS

According to Behe, the cilium and bacterial flagellum are just the beginning of the Darwin-defying complexity in the microscopic world of the cell. One of his other favorites is the “intra-cellular transport system.”

“The cell is not a simple bag of soup, with everything sloshing around,” he said. “Instead, eukaryotic cells—cells of all organisms except bacteria—have a number of compartments, sort of like rooms in a house.

“There’s the nucleus, where the DNA resides; the mitochondria, which produce energy; the endoplasmic reticulum, which processes proteins; the Golgi apparatus, which is a way station for proteins that are being transported elsewhere; the lysosome, which is a garbage disposal unit; secretory vesicles, which store cargo before it’s sent out of the cell; and the peroxisome, which helps metabolize fats. Each compartment is sealed off by a membrane, just like a room has walls and a door. In fact, the mitochondrion has four separate sections. Counting everything, there are more than twenty different sections in each cell.

“Cells are constantly getting rid of old stuff and manufacturing new components, and these components are designed to work in one room but not others. Most new components are made at a central location in the cell on things called
ribosomes
.”

Denton has described the ribosome, a collection of some fifty large molecules containing more than one million atoms, as an automated factory that can synthesize any protein that it is instructed to make by DNA. Given the correct genetic information, in fact, it can construct any protein-based biological machine, including another ribosome, regardless of the complexity. Denton marveled:

It is astonishing to think that this remarkable piece of machinery, which possesses the ultimate capacity to construct every living thing that has ever existed on Earth, from a giant redwood to the human brain, can construct all its own components in a matter of minutes and . . . is of the order of several thousand million million times smaller than the smallest piece of functional machinery ever constructed by man.
¹¹

“Not only is the ribosome amazing,” Behe said, “but now you’re faced with the challenge of getting these new components into the right rooms where they can operate. In order to do that, you need to have another complicated system, just like you need a lot of things in place for a Greyhound bus to take someone from Philadelphia to Pittsburgh.

“First of all, you’ve got to have molecular trucks, which are enclosed and have motors attached to them. You’ve got to have little highways for them to travel along. You’ve got to be able to identify which components are supposed to go into which truck—after all, it doesn’t do any good if you just grab any protein that comes along, because each one needs to go to a specific room. So there has to be a signal attached to the protein—sort of a ticket—to let the protein onto the right molecular truck. The truck has to know where it’s going, which means having a signal on the truck itself and a complementary signal on the compartment where the truck is supposed to unload its cargo.

“When the truck arrives where it’s supposed to go, it’s kind of like a big ocean liner that has crossed from London to New York. It pulls up at the dock and everyone’s waving—but, oops, they forgot the gang plank. Now what are you going to do? You see, you’ve got to have a way for the cargo to get out of the truck and into the compartment, and it turns out this is an active process that involves other components recognizing each other, physically opening things up, and allowing the material to go inside.

“So you’ve got numerous components, all of which have to be in place or nothing works. If you don’t have the signal, if you don’t have the truck, you’re pretty much out of luck. Now, does this microscopic transportation system sound like something that self-assembled by gradual modifications over the years? I don’t see how it could have been. To me, it has all the earmarks of being designed.”

THE BLOOD-CLOTTING CASCADE

There was a pause in our conversation as my mind processed the stupefying complexity of the cilium, flagellum, and intracellular transport system. As I began to formulate my next line of questioning, Behe noticed a Band-Aid on one of my fingers, covering a cut I had received while picking up pieces of broken glass the previous day.