Undeniable (24 page)

Creationists will say that they accept microevolution—for instance, the way one strain of virus can mutate into another, a mutation for which our body's library of antibodies finds no match. It would be hard to deny that, since it happens every year at flu season. But then they'll turn around and insist that we have nothing in common with the other creatures here on Earth, because a higher power must have taken the time to make humans different. They use the term
microevolution
for the part of evolution that they find theologically acceptable. They use
macroevolution
for the part they don't like, perhaps because it's too disturbing. For them, macroevolution can't be real, because it cannot be reconciled with their belief that they are special, chosen for special treatment.

As you may know, creationists have gone to extraordinary lengths to reconcile their beliefs with the world as we see it. They've invented terms and written stories to try to make the incredible credible. Reading
The Bible
as written in English, they've coined a nominally Hebrew-derived word
baramin
to describe 7,000 kinds of plants and animals that were supposed to be on a boat 4,000 years ago and have since developed (through microevolution … that somehow turned macro) into 16 million species. They even use the phrase “mutation selection” to describe processes we all can observe in nature, like the London Underground mosquito speciation. But they don't accept the big picture of our common ancestry with every other living thing and the evidence for deep time and the age of Earth.

Here's the punch line: None of the micro ideas make any sense except in the context of the macro, and vice versa. Microevolution is just the raw material from which macroevolution occurs. This is a case in which scientific concepts become confusing, even misleading, when taken out of context. The bottom line is that nature doesn't care what words you use.

Creationism strikes me as an astonishing waste of time and energy. I would love to be able to ignore it and focus on the real science, but creationists work very hard to disrupt science education and force their weird worldview on our students. So let's make the best of an unfortunate situation, and use the creationist attacks as a learning opportunity. When you hear the terms
microevolution
and
macroevolution
, be attentive to who's using them. Think about how evolution works, on all scales of space and time. Viruses mutate from day to day. Fish evolved into land animals and eventually begat dinosaurs and blue whales, over hundreds of millions of years. It's a beautiful, complicated story on all scales.

So please: Think big, and think critically.

 

24

MICHAEL FARADAY AND THE JOY OF DISCOVERY

If you believe public opinion polls, about half of the American public does not accept the proposition that life on Earth—including humans—is the product of billions of years of natural evolution. At the same time, these same people seem to accept everything else that scientific discoveries and diligent engineering bring us. They don't doubt the chemical synthesis in their food, the electrical physics in their smartphones, or the relativistic corrections (Einstein's theory of relativity) that keep their GPS (Global Positioning System) signal accurate. Perhaps, as I speculated earlier, fear is part of what holds many people back from embracing evolution. If so, that puts a special responsibility on the scientists and those of us who write about them. If fear is pulling people one way, then we have a public responsibility to pull people back the other way and offer something just as powerful, something wondrous.

Too often, this is not what happens. I have met a great many people, who have told me that they were exposed to science in a joyless way. They were forced to learn about science as a series of obscure facts with a bunch of confusing equations to memorize. They were given a general sense that the world is difficult and a bit annoying to see through the eyes of a scientist. My, oh my, do I have a different view of the world. Let me tell you a story that still drives me wild.

From time to time, people ask me: If you could meet anyone in history, who would it be? I have a quick and easy answer: British genius Michael Faraday, the man who learned how to put electricity to practical work and one of the greatest science communicators in history. By 1800, many scientists across Europe were busily experimenting with electricity. Alessandro Volta built piles of plates separated by saltwater-soaked cloth or cardboard. The plates were alternating layers of copper and zinc. Such piles produce what he called electro-motive-force, which we now call voltage. André-Marie Ampère showed the relationship between the intensity of electricity and the magnetic force it produces. We now have the unit of electric current called the ampere, or amp. Michael Faraday figured out many of the crucial details about how electricity works. Among other things, he built the world's first electric motor. He also shared his ideas with the public in an exuberant style.

In 1825, Faraday began a series of lectures at the Royal Society in London called the Christmas Lectures. These were for a general audience, including kids, and have been delivered every year since, except while London was being bombed during World War II. Carl Sagan was one of the more notable modern Christmas Lecturers, in 1977. These are lectures with words, to be sure, but they are also performances featuring wonderful science demonstrations and showmanship. After several years of investigation in his laboratory, Faraday perfected a demonstration that goes like this: On a lab bench or table, about two meters (6 feet) long, Faraday set up two coils of wire that were connected by parallel wires, like a toy train track with tunnels at each end. In the center of one of the coils, on a suitably shaped block of wood, he set a magnetic needle compass.

Magnetism had been known for centuries; Christopher Columbus relied on a magnetized needle mounted on a suitably shaped floating block of cork to guide his ships. But Faraday took magnetism into new territory. With the compass in a coil at one end of the bench, Faraday moved a bar magnet in and out of the other coil at the other end of the bench. The compass needle moved. You can try this and get the same result. A magnet moving at one side of the stage caused a magnetic needle to move at the other end of the bench.

This may sound like no big deal. Many of you reading right now may have played with magnets and compasses (and perhaps ruined a few with too much magnetism too close to the delicate needle of the compass). It's reasonable that others had noticed that when electricity flows through a wire, a magnetic field is created around the wire, which can easily influence a compass needle. But Faraday realized what apparently no one before him realized: The process also works the other way around. If you have a magnet move near a wire, you get electricity in the wire. Faraday observed and carefully described the key idea. It's not that there's a magnet; it's that there is a
moving
magnet, a
moving
magnetic field.

At the Christmas Lecture, Faraday didn't just put a magnet near the wire. Instead, he made the magnet move, which in turn created a moving magnetic field. His audience was captivated, and so were his fellow scientists. Almost everything you touch and see all day long owes its existence to Faraday's discovery, because this is how we generate electricity. Just look around; what would be in your field of view without electricity? Hardly anything! Lights, televisions, computers, refrigerators, and coffeemakers would not otherwise be here. Everything that's manufactured—tables, chairs, cars, streets, carpets, tiles, clothes—now depends on electricity. Food is raised on farms that depend on machinery and transportation systems. This book was written using electricity and published using electricity, whether you are listening to my voice, or reading on paper or on a screen.

Saving the best for last: A woman came up to Michael Faraday after he performed this demonstration and asked: “But, Mr. Faraday, of what use is it?” Faraday famously replied, “Madam, of what use is a newborn babe?”

I hope you can feel Faraday's incredulity. You've got to admire him for not coming unglued. He could have said something like, “Lady, are you daft?! This is not a big deal to you!? Did you notice, for cryin' out loud, that I am not … I mean no one is … touching the compass?! Some force is passing from this end of the table to that end of the table, and that piece of metal is moving as though a witch were over there casting some sort of spell! By the stars, woman, this is utterly astonishing…” William Gladstone, when he was Chancellor of the Exchequer in England, reportedly asked Faraday a similar question. This time, Faraday responded—with perhaps more malice—“Why, sir, there is every probability that you will soon be able to tax it.”

When I reflect on this story, I keep thinking about how much pleasure Faraday took in demonstrating his discovery and sharing it with the world. He got joy from it every single time. Darwin, I'm sure, felt the same joy of discovery. But it was different for Darwin than it was for Faraday, because Darwin's discovery was so troubling for so many on religious and philosophical grounds. The discovery of evolution led us to a line of thinking that, for many, diminishes our importance in the scheme of things. Darwin himself wrestled with the implications of his discoveries, as did his devout wife. Faraday had no such complicated emotions toward electricity. He also, like few scientists before or since, thrilled at sharing his ideas with those around him. His lectures were packed, exciting events because he spoke about science with unfiltered passion, and without a trace of pretense or jargon.

Evolutionary science could use a spokesperson like Michael Faraday. For me, learning about our place in the great chain of life is anything but sad. For me, and I'm sure Faraday would have agreed, scientific discoveries are joyous. In studying evolution, we find the hidden explanation for tyrannosaur fossils, our tailbones, and the common cold. Here we uncover the secrets to life on Earth. It is science, but it is a process driven by the human spirit. For me, there is nothing more exciting. It reminds me of another famous Faraday quotation: “Nothing is too wonderful to be true, if it be consistent with the laws of nature.”

 

25

MEDICINE AND YOU—EVOLUTION AT THE DOCTOR'S OFFICE

My father and his high school buddy Phil were excellent Boy Scouts. They could both start a fire in the rain. They could tie knots that most of us have never heard of—blindfolded. When I was a little kid, Phil's wife got skin cancer; her face swelled up horribly. All his practical talents were useless to combat this disease. So were all the talents of medicine. Phil's wife was a serious Christian Scientist who believed that if someone got sick, the affliction could be overcome by seeking the aid of a divine power. She refused treatment, the cancer metastasized, and she died. It was hard on everyone; the experience broke Phil's heart, and my dad's and my mom's hearts, too. Even back then, Phil's wife could have had the malignancy removed and probably would have lived decades longer. Nowadays the gap between what doctors can do and what Phil's wife would embrace is even wider. Medical treatments have improved drastically, and evolutionary research is a major reason why.

This is an important aspect of evolution that many people don't appreciate. Evolutionary science is not just about the history of life. It is a research program with very immediate, tangible benefits. It guides modern medicine. For instance, we've discovered that cancer evolves. Cancer cells can mutate in the body of a patient, so that malignant cells find new ways to get a supply of blood and become resistant to our anticancer drugs. We can use hormones from other animals—like insulin derived from pigs—to treat people because we came to understand our common ancestry. Medical researchers create new vaccines every summer to anticipate the evolved, mutated flu virus that will make the rounds in the autumn. The connections go on and on.

In one form or another, humans have been practicing medicine for millennia. African tribes drilled holes in each other's skulls to relieve fluid pressure. First Nation tribes in North America developed several pain-relief medicines. Humans everywhere developed techniques for the treatment and healing of broken bones. It is a consequence of having enough brainpower to figure out causes and effects in our own human bodies. The medicine we practice today is fundamentally different from the way that humans dealt with diseases and injuries through most of our history on Earth, however.

The difference is that today's medical practitioners can draw on predictions made by our understanding of evolution. As any biologist will tell you, living things everywhere on our planet have an astonishing number of things in common. We are made of cells. We have the instructions to build any one of us in almost every one of our cells; we all have DNA. We all reproduce in the midst of all the world's other living things. As we do, subtle changes get built into each succeeding generation. Today's drugs and vaccines are possible because of these insights.

Recently, the evolutionary aspects of medicine have taken a surprising turn. Doctors are starting to look at evolution not only as something that affects human health from the outside, but from the inside as well. They are thinking of each person as a walking, evolving ecosystem. I admit you might not think of yourself as an ecosystem. At least, not yet.

Most of the living things on this planet are made of a single cell with no nucleus in the middle. Most Earthlings are microorganisms. You probably have no trouble accepting that. Now try this: Even the majority of the cells
in your body
are microorganisms. They outnumber the cells of your body by 10 to 1. Those microbes are living, metabolizing chemicals, producing waste chemicals, and interacting with each other. Collectively, they are known as your microbiome. You are their ecosystem. It's wild.