Mind-Buzzing Science


If a child is to keep alive his inborn sense of wonder, he needs the companionship of at least one adult who can share it, rediscovering with him the joy, excitement, and mystery of the world we live in.

—Rachel Carson, The Sense of Wonder

Science, as a way of engaging the world, is the new kid in town. There’s evidence of religious belief and practice in Neanderthal burials over 40,000 years ago, but science and the scientific method as we understand them today didn’t truly take hold until the sixteenth century—the last one percent of the known history of religion. Yet in that blip of time, the infant called science has doubled the human life span, conquered countless diseases, taken us up off the planet and down into the microscopic world, measured the age and size of cosmos, discovered the laws of nature—and yes, made possible weapons of mass destruction, CFCs, and many other environmental and human catastrophes.

Imagine what the toddler years have in store.

Science—from Latin scientia, “to know”—is a tool, a method, a process, and can be used for good or ill. But one thing remains indisputable: It is our very best means of gaining actual knowledge. This chapter is a celebration of the ability of science to reveal reality, but even more so of its ability to amaze and inspire us as it does so.

Childhood is the natural home of wonder. At no other time in our lives are we as open to the experience of wonder. If religion were the only available means to it, I would be religious—wonder means that much to me, and I want wonder and inspiration in my children’s lives just that much. Fortunately, no such compromise is needed. The essay “Teaching Kids to Yawn at Counterfeit Wonder” argues that scientific wonder leaves the religious variety far behind—and that all a parent really needs to do is point it out. If that. Amanda Chesworth, director of CSICOP’s1 Inquiring Minds program for kids, suggests that one of the great joys of parenthood should be offering “brain food” to the ravenous young mind, and Yip Harburg chimes in with a poem about a confused ape in “We’ve Come a Long Way, Buddy.”

Over half of the chapter is devoted to Kristan Lawson’s “The Idea That Changed the World,” a thorough but accessible explanation of the theory of evolution. This is one of the most important pieces in this book, for more than any other idea in human history, Darwin’s description of evolution by natural selection remade our understanding of the world and our place in it. Copernicus took us out of the center of the universe, but Darwin’s “decentering” was far more personal. It was also more beautiful, taking us from a cold pedestal above our fellow creatures to a deep kinship with them. And, as philosopher Daniel Dennett notes, it made disbelief in God “intellectually respectable” by explaining at last the immense complexity of life on Earth and the astonishing illusion of design that had seemed, for so many centuries before, to necessitate a designer.

Yet poll results consistently show only about a third of Americans accepting evolution as true, and most of these still put God at the helm of the process—an idea that can only be sustained by completely misunderstanding what natural selection means. That percentage is the lowest in the developed world. Even among the third who do accept it are very few who have made the effort to understand it, to really understand it. You’d think it was impossibly technical, hopelessly inaccessible. It isn’t, and Lawson proves that. Neither is it a piece of cake—some concentrated attention is required—but an aboveaverage middle schooler will be up to the task.

Having no theological implications to fret over gives secular families an enormous advantage. We can walk right into the awe-inspiring space opened up by Darwin’s insights and revel in every implication without fear of having pet dogmas dethroned. That is why Lawson’s essay is included: so that when at last a child expresses an interest in knowing where we came from and how we fit into the puzzle of life—regardless of whether their local school boards or legislatures have watered down or pushed out evolution—parents will have the right resource at hand. At the end of a mere twenty pages of text and great activities, the child (or the parent, for that matter!) will have joined the very select group of people who have known, really known, who we are—by learning about the most world-shaking idea anybody ever had.

Teaching Kids to Yawn
at Counterfeit Wonder

Dale McGowan, Ph.D.

A LOT OF PEOPLE BELIEVE that you can’t experience wonder without religious faith. The life of a person without supernatural beliefs is thought to be cold, sterile, and lifeless.

If that were the case, this book would have to sound the alarm. Childhood, after all, is our first and best chance to revel in wonder. If parenting without religion meant parenting without wonder, I might just say to heck with reality.

Funny, though, how often I’ve experienced something that seemed an awful lot like wonder. It couldn’t have been actual wonder, I’m told, since real wonder comes only from contemplation of God and a knowledge that he created all that is.

Call me Ishmael, but that never did much for me. I always found the biblical version of wonder rather flat and hollow, even as a kid. It never moved me even as metaphor, rendered pale by its own vague hyperbole.

Now try these on for size:

1. If you condense the history of the universe to a single year, humans would appear on December 31st at 10:30 PM—99.98 percent of the history of the universe happened before humans even existed.

2. Look at a gold ring. As the core collapsed in a dying star, a gravity wave collapsed inward with it. As it did so, it slammed into the thundering sound wave heading out of the collapse. In that moment, as a star died, the gold in that ring was formed.

3. We are star material that knows it exists.

4. Our planet is spinning at 900 miles an hour beneath our feet while coursing through space at 68,400 miles per hour.

5. The continents are moving under our feet at 3 to 6 inches a year. But a snail’s pace for a million millennia has been enough to remake the face of the world several times over, build the Himalayas, and create the oceans.

6. Through the wonder of DNA, you are literally half your mom and half your dad.

7. A complete blueprint to build you exists in each and every cell of your body.

8. The faster you go, the slower time moves.

9. Your memories, your knowledge, even your identity and sense of self exist entirely in the form of a constantly recomposed electrochemical symphony playing in your head.

10. All life on Earth is directly related by descent. You are a cousin not just of apes, but of the sequoia and the amoeba, of mosses and butterflies and blue whales.

Now that, my friends, is wonder.

I was first introduced to genuine, jaw-dropping, mind-buzzing wonder as a teenager by Carl Sagan. Carl was a master of making conceivable the otherwise inconceivable realities of the universe, usually by brilliant analogy, taking me step by step into a true appreciation of honest-to-goodness wonder. I was aware, for example, that humans were relative newcomers on the planet, but it wasn’t until I came across Sagan’s astonishing calendar analogy at the age of 13—the one above that puts our arrival at 10:30 PM on New Year’s Eve—that I actually got it, and swooned with wonder.

A little precision can make all the difference in the experience of wonder. Merely knowing that the universe is really really really really big is one thing, but that only rated a two on the wow-meter for me as a child, as it does for my son and daughters. A few more specifics, though, can snap it into focus, and up goes the meter.

Put a soccer ball in the middle of an open field to represent the sun. Walk twenty-six paces from the ball and drop a pea. That’s Earth. An inch away from Earth, drop a good-sized breadcrumb for the Moon, remembering that this inch is the furthest humans have been so far. Jupiter is a golf ball 110 paces further out, and Pluto’s a tiny BB about a half mile from the soccer ball.

So how far would you have to walk before you can put down another soccer ball for Proxima Centauri, the very nearest star to our Sun? Bring your good shoes—it’s over 4,000 miles away at this scale, New York to Berlin. That’s the nearest star. And there are about a trillion such stars in the Milky Way galaxy alone, and roughly a hundred billion such galaxies, arrayed through 12 billion of those light years in every direction, a universe made of a curved fabric woven of space and time in which hydrogen, given the proper conditions, eventually evolves into Yo Yo Ma.

Two hundred years ago it was possible, even reasonable, to believe that we were the central concern of the Creator of it all—and therefore reasonable to teach our children the same. But anyone who was engaged for the whole process above will still be blank-eyed and buzzing at all we have learned about ourselves and our context in the past two centuries. Just as infants mature into adults by gradually recognizing that they are not the center of the universe, so science has given humanity the means to its own maturity, challenging us not only to endure our newly realized smallness, but to find the incredible wonder in that reality.

Religious wonder—the wonder we’re said to be missing out on—is counterfeit wonder. As each complex and awe-inspiring explanation of reality takes the place of “God did it,” the flush of real awe quickly overwhelms the memory of whatever it was we considered so wondrous in religious mythology. Most of the truly wonder-inducing aspects of our existence—the true size and age of the universe, the relatedness of all life, microscopic worlds, and more—are not, to paraphrase Hamlet, even dreamt of in our religions. Our new maturity brings with it some real challenges, of course, but it also brings astonishing wonder beyond the imaginings of our infancy.

There is no surer way to strip religion of its ability to entice our children into fantasy than to show them the way, step by step, into the far more intoxicating wonders of the real world. And the key to those wonders is precisely the skill that is so often miscast as the death of wonder: skepticism.

Nothing wrinkles noses faster than a skeptical attitude—“Why do you have to be so negative, why do you have to tear everything down?”—yet there is nothing as essential to experiencing true wonder in its greatest depth. Skepticism is the filter that screens out the fool’s gold, leaving nothing behind but precious nuggets of the real thing. Tell me something amazing, and I’ll doubt it until it’s proven. Why? Because fantasies, while charming, are a dime a dozen. I can tell you my dreams of purple unicorns all day, spinning wilder and wilder variations for your amusement. You’ll enjoy it, perhaps even be moved by it, but you won’t believe—until I show you one, take you for a ride on its back, prove it’s more than just a product of my imagination. Your skepticism up to that point will have served you well; it fended off counterfeit wonder so you could feel the depth of the real thing.

After sleeping through a hundred million centuries, we have finally opened our eyes on a sumptuous planet, sparkling with colour, bountiful with life. Within decades we must close our eyes again. Isn’t it a noble, an enlightened way of spending our brief time in the sun, to work at understanding the universe and how we have come to wake up in it? This is how I answer when I am asked—as I am surprisingly often—why I bother to get up in the mornings.

—Richard Dawkins, Unweaving the Rainbow

We must teach our kids to doubt and doubt and doubt not to “tear everything down” but to pull cheap façades away so they can see and delight in those things that are legitimately wonderful. How will they recognize them? It’s easy—they’re the ones left standing after the hail of critical thinking has flattened everything else. Magnificent, those standing stones.

Supporters of the scientific worldview are sometimes accused of having “faith” in ideas such as evolution and therefore practicing a sort of religion. The less you know, the more reasonable that assertion is. Evolution by natural selection was positively barraged with skepticism throughout the end of the nineteenth century and well into the twentieth. Darwin and Huxley spent the remainder of their lives answering doubts about the theory. And, when the dust cleared, the theory remained, intact, beautiful in its inevitability, awe-inspiring not because it drew no fire but because it drew the fire and survived spectacularly. That is what is known as the truth, or our best approximation of that elusive concept. It is so precious to get a glimpse of real knowledge, so breathtaking, that no lesser standard than trial by skepticism will do. It leaves behind only those things wonderful enough to make us weep at the pure beauty of their reality and at the equally awesome idea that we could find our way to them at all.

A theologian friend of mine once suggested to me that the metaphors of religion are beautiful “responses to mystery.” If, each time a mystery is dispelled by real understanding, the metaphor stepped aside, ceding the ground of wonder to its successor, there would be no problem with such metaphors. The problem—as illustrated by the creation/evolution “controversy”—is that we fall so deeply in love with our metaphors that we are often unable and unwilling to let go when the time comes and mystery is replaced with knowledge. “If you are awash in lost continents and channeling and UFOs and all the long litany of claims,” Carl Sagan said, “you may not have intellectual room for the findings of science. You’re sated with wonder.” It’s this all-too-human tendency that presents a challenge for parents wishing to raise independent thinkers: the magnetic power of the lovely metaphor, standing in the doorway, impeding progress toward real answers.

The most compelling cases of preferring fact to fiction are the most practical. All the prayer, animal sacrifice, and chanting in the world couldn’t cure polio—the Salk vaccine did. And how did we find it? Through rigorous, skeptical, critical thinking and testing and doubting of every proposed solution to the problem of polio until only one solution was left standing. Let others find uncritical acceptance of pretty notions a wonderful thing. I’m more awestruck by the idea of ending polio because someone cared enough to find more wonder in testable reality than in wishful fantasy.

Some would protest, rightly, that science stops at the measurable, that those things that cannot be quantified and calculated are beyond its scope. That’s entirely true. But the foundation of reality that science gives us becomes a springboard to the contemplation of those unmeasurables, a starting point from which we dive into the mystery behind that reality. Our reality has astonishing implications and yields incredible mystery, questions upon questions, many of them forever unanswerable. But is it not infinitely better to bathe in what we might call the genuine mystery behind our actual reality, instead of contemplating the “mystery” behind a mythic filial sacrifice, or transubstantiation, or angels dancing on the head of a pin?

It’s easy to get a child addicted to real wonders if you start early enough. Simply point them out—they are all around us—and include a few references to what was once thought to be true. Take thunder. Explain that a bolt of lightning rips through the air, zapping trillions of air molecules with energy hotter than the Sun. Those superheated molecules explode out of the way with a crack! Then the bolt is gone, and all those molecules smash into each other again as they fill in the emptiness it leaves behind. That’s the long rumble—waves of air swirling and colliding like surf at the beach.

Forgive me if I find that completely wonder-full.

Then explain that people once thought is was a sound made by an angry god in the sky, and enjoy your child’s face as she registers how much less interesting that is.

Repeat steps one and two until college.


Natural Wonders

Amanda Chesworth

NOT SO LONG AGO, FEAR was believed to be an indispensable tool in educating the young. Consider the picture painted by James Joyce in Portrait of the Artist as a Young Man. Stephen Dedalus was in class when

The door opened quietly and closed. A quick whisper ran through the class: the prefect of studies. There was an instant of dead silence, and then the loud crack of a pandybat on the last desk. Stephen’s heart leapt up in fear. “Any boys want flogging here, Father Arnall?” cried the prefect of studies. “Any lazy, idle loafers that want flogging in this class?”

Fear has been used throughout history as a weapon to control the masses. The institution of religion has been especially successful in using fear to make people conform and yield to its power. Fear is the destroyer of inquiring minds. The wonder and curiosity inherent in a child are at risk of being annihilated through faith-based education. “There is another form of temptation even more fraught with danger,” warned Saint Augustine. “This is the disease of curiosity. It is this which drives us on to try to discover the secrets of nature, those secrets which are beyond our understanding, which can avail us nothing, and which men should not wish to learn.”2

Fortunately we live in a more enlightened age. “The great human adventure,” says humanist philosopher Paul Kurtz, “is to live creatively and exuberantly…. Courage is still the first humanistic virtue; it is out of this fearless posture and because of it that men and women were able to leave the caves of primitive existence and to build civilizations. It is the continuing human adventure that captivates and enthralls us…. If the human species is to survive and embark upon exciting new voyages of wonder and discovery, it will be only because it can still marshal the determination to take responsibility for its own destiny and the courage to fulfill its unique ideals and values, whatever they may be. It will always need the courage to become.” 3

There will always be those, however, who hanker after the “good” old days. On one telecast of The 700 Club, Pat Robertson suggested that “It is absolutely impossible to have genuine education without the holy scriptures.” I contend that a humane, pragmatic, and ever-evolving approach is the only one justified if our ultimate goal is to nurture the wonder in children, giving them the chance to grow into decent human beings with a passion for life and learning. Not many theories of education that came out of the hothouse of social science qualify as theories, or even as hypotheses. They have not been repeatedly tested, no rigorous attempts are made to falsify them (indeed, some may be unfalsifiable and therefore completely unscientific). On the whole I suspect that they would be better classified as cultural myths, alongside the tenets of dogmatic religion.

Raising a child according to fixed notions, using fear and reward as incentives and encouraging students to memorize the information provided, are teaching strategies utterly devoid of life and ultimately useless, if not damaging, to our future. They run contrary to our evolutionary heritage, where wonder and curiosity play an integral role in our survival.

Attorney Clarence Darrow noted that “The origin of what we call civilization is not due to religion but to skepticism. The modern world is the child of doubt and inquiry, as the ancient world was the child of fear and faith.”4

In a spirit of simple pragmatism, let’s consider what you have to work with as a parent. What is it that makes it relatively easy to teach a child? Perhaps the most helpful and wonderful thing about childhood in this regard is the newness of everything. Every child stands at the morning of the world; every day is a voyage of discovery in which your sons and daughters are as intrepid as Magellan. Yours is the immense privilege of providing these bright, awakening minds with brain food.

Science and wonder are natural companions, notes Oxford biologist Richard Dawkins:

We have an appetite for wonder, a poetic appetite, which real science ought to be feeding but which is being hijacked, often for monetary gain, by purveyors of superstition, the paranormal and astrology…. Since the appetite for wonder is fed so much more satisfyingly by science, it ought to be a simple matter of education to combat superstition.5

There are many kinds of brain food available. What you choose will depend on a variety of personal factors including your own interests and environment. My own inclination is toward the concrete, leaving the abstract to develop once the child has a good grasp of the real world outside his or her head. Our beginning explorer sees a world uncluttered by theory and paradigms, a world that is tangible, colored, wet or dry, sweet- or foul-smelling—and above all, immediate. It attracts or frightens, assaulting the senses from all directions. It is the source of wonder: A colorful bird flying above my head, a purple stone beneath my feet, a train rumbling down the tracks before its sound is drowned out by a jet plane soaring through the skies, snow falling gently onto the tip of my tongue, stars twinkling and forming patterns in my mind. There is an infinite supply of wonder around me, with new amazements arriving daily. As my understanding grows, my world becomes brighter, my life more fulfilled. I walk hand in hand with science.

Mystery is a very necessary ingredient in our lives. Mystery creates wonder and wonder is the basis for man’s desire to understand. Who knows what mysteries will be solved in our lifetime, and what new riddles will become the challenge of the new generation? Science has not mastered prophecy.

–Neil Armstrong, in a 1969 speech to Congress

As a child you learn the magic word “why” and drive your parents and teachers nuts with it. If they don’t give you a concrete answer that you can understand, you continue with a string of “whys” until they do.

There are many ways of answering the word “why.” Kipling’s Just So Stories illustrate one technique—and a valuable one for stimulating the imagination. The story “explains” how the camel got its hump: When the genie told him not to be so lazy, the camel said “Humpf!”—and the genie punished him by putting the humpf on his back. Not a very convincing explanation, even in the unlikely event that humpf was the original spelling of hump, but a fun and satisfying “child’s play” version of inquiry and learning, of asking why and finding out.

The Just So Stories of science are even more stimulating because they are based on our long experience of the real world outside our heads, the very world to which the child is awakening. It’s a world where you can’t get something out of nothing, a concept a child can easily grasp—and, with growing maturity, may learn to call the conservation of matter. Think of the story of Humpty Dumpty and the fact that all the king’s horses and all the king’s men couldn’t put him together again. It’s the second law of thermodynamics in nursery rhyme form. A famous thermodynamicist named Myron Tribus once said to a class that all actions are reversible. Okay, said one student—how do you unscramble an egg? Feed it to a chicken, he replied. Maybe that’s what all the king’s horses and all the king’s men should have done. (It doesn’t lead to true reversibility, or course—you wouldn’t get Humpty Dumpty … just another egg!)

Curiosity has its own reason for existence. One cannot help but be in awe when one contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day.

–Albert Einstein

Many of the important default positions of science, outlined by Garrett Hardin in Learning to Live within Limits, can be grasped in rudimentary form by a child. Gradually, and with appropriate guidance, their explorations lead them to an appreciation of reliable default positions. They learn that we live on a finite planet and share a biosphere with countless other species and that the implacable competition that takes place there, the process we call natural selection, has shaped us and other species into the organisms that we are.

What you want your child to have is an acquaintance with those default positions that allow him or her to discriminate between reliable knowledge and unreasonable speculation. That, ultimately, is the true wonder of science—the ability to spot the reasonable “just so stories.”

The importance of reaching this state was expressed well by the fine scientific journalist Judith Stone in Discover magazine:

We can’t all be Einstein … At the very best, we need a sort of street-smart science: the ability to recognize evidence, gather it, assess it and act on it. As voters, we’re de facto scientific advisors…. If we don’t get it right, things could go very wrong.6

Street-smart science begins with our young Magellans asking “why” as they set off to explore our magnificent universe. With any luck the voyage will lead to a lifetime of intellectual excitement. And when finally they are ready “to sail beyond the sunset, and the baths of all the western stars,” as Tennyson put it, they will consider their lives well spent.


Celebrating the wonder of science is the focus of Inquiring Minds, a program sponsored by the Center for Inquiry (CFI) and the Committee for the Scientific Investigation of Claims Of the Paranormal (CSICOP). It serves as a resource for educators, parents, and children and works to complement both formal and informal science education within our communities. A primary goal of Inquiring Minds is to prepare children to use their magnificent brains to navigate effectively through the minefield and make choices that are reasonable and safe. They are provided with the tools to reach their own conclusions. Ultimately the skepticism and independent thinking promoted within our organization may help children to lead fuller, happier lives, based on their realization that they have developed the intellectual backbone to resist the outrageous claims and messages that, 200 years after the “Age of Enlightenment,” we are still prey to.

The young are the future of civilization. We need to nurture the wonder inherent within us and encourage young people to flourish. We share Carl Sagan’s belief that science is our candle in the dark, a candle to light our children’s future. Visit

We’ve Come a Long Way, Buddy

Yip Harburg

An ape, who from the zoo broke free,
Was cornered in the library
With Darwin tucked beneath one arm,
The Bible ’neath the other.
“I can’t make up my mind,” said he,
“Just who on earth I seem to be—
Am I my brother’s keeper
Or am I my keeper’s brother?”


The Idea That Changed the World

(Chapter 6 from Darwin and Evolution for Kids)

Kristan Lawson

Darwin’s Theory of Evolution

EVEN THOUGH THE WORDS “Darwin” and “evolution” are familiar to almost everyone, very few people understand how Darwin’s theory of evolution actually works. This chapter will explain it in terms that anyone can comprehend. Before you can fully grasp it, however, you’ll need to be familiar with a few key concepts.


No two creatures are exactly the same. If you have brothers and sisters, look at them and compare them to yourself. Are all the children in your family the same height? Do they all have the same shoe size? Same shape of nose? Are some smarter than others? Can some run faster? Are some braver, shyer, or nicer than others? The more you look, the more differences you’ll find. Yet you and your siblings have the same parents. Doesn’t that mean you should be exactly alike? The answer is no. Every individual person or animal is a unique combination of genes inherited from his or her parents. Like snowflakes, no two individuals can be precisely the same as each other. Even small animals that all look alike—such as mice or goldfish—are, when inspected closely, different from each other in one way or another. These differences between similar creatures are called variations.

First appeared in Darwin and Evolution for Kids,© 2003. Used with permission of Chicago Review Press.

The biological reasons for variation were not discovered until the twentieth century, long after Darwin’s lifetime. But, like Darwin, we don’t need to be experts in genetics to know that variation occurs all the time. It’s easy enough to observe variations with your own two eyes.


Did you ever notice that children tend to look like their parents? No one is ever an exact copy of his or her mother or father, but parents and kids are always somewhat similar. Does your mother have two arms, two legs, two eyes, a head, ten fingers, a mouth, and a brain? Then you do as well. If your parents have big noses, odds are you’ll have a big nose too. If your parents have brown skin, you will have brown skin. If your parents are short, you’ll probably be short. This is true in every family.

And it’s not just true in human families. A Siamese cat will always give birth to Siamese kittens—it will never give birth to a puppy, an alligator, or even a different breed of cat. This may seem obvious, but it’s an important aspect of evolution. Even the smallest features can be passed on from parent to offspring. The word for this is heritability. As with variation, the exact biological cause for heritability was not discovered until after Darwin had died. Even so, farmers, animal breeders, and parents all over the world know that heritability is one of the basic features of all species.


In the natural world, all animals and plants produce many more offspring than can ever survive. For example, think about a pair of adult rabbits. The average female rabbit gives birth to a litter of four baby rabbits, five times a year. (Many types of rabbits can have more offspring than this per year; this is just an average.) After one year, that first pair of rabbits will have made 20 baby rabbits (4 babies × 5 times a year). Half of these (10) will be female rabbits. Each of these 10 young female rabbits will grow up; after about six months they can start having babies of their own. After another year, all of the 10 female rabbits will themselves each have given birth to 20 or more rabbits—10 females and 10 males. Now you’ll have at least 200 rabbits (10 mothers x 20 babies). The next year those 100 female rabbits will produce 1,000 more females. Then 10,000, then 100,000, and so on. After only twelve years you’ll have over a trillion rabbits! Soon enough, the entire world would be completely covered in rabbits.

Now imagine this: The same tendency to overpopulate is true for almost every species. Frogs and goats and bees and fish and pigeons and a million other kinds of animals. The name for this tendency of organisms to produce more offspring than they need is superfecundity. If every baby animal survived, there would be uncountable numbers of every kind of animal filling every square inch of the planet, with millions more appearing every day, without end.

But this obviously isn’t the case. So, where do they all go?

The Age of the Earth

In Darwin’s time, no one really knew how old the Earth was. Some people thought it was only 6,000 years old. Others thought perhaps 30,000 years, or 100,000. But discoveries in geology and paleontology throughout the nineteenth century indicated that the planet was much older than that—millions of years old, at least. Darwin knew that evolution took a long time to happen, so he was very concerned with proving that the Earth had been around for a long time.

He need not have worried. It was not until the twentieth century that scientists were first able to accurately measure the Earth’s age, using very sophisticated techniques. We now know that the Earth is about 4.5 billion years old! That’s hundreds of times older than anyone in Darwin’s era even imagined. And it’s more than enough time for evolution.

Activity: Make Your Own Geological Strata

Early geologists proved that the Earth was at least many millions of years old by inspecting geological strata visible in exposed cliffs. This proof of the planet’s age was an important factor in the acceptance of the theory of evolution, because animals need a long time to evolve. It’s not always easy to find a place near your home where real strata are visible, but you can make your own strata with material you find in your backyard and kitchen.

What you need

a tall glass jar with a lid, preferably with the label removed several plastic or paper cups

Choose five to eight of the following:

dark soil

light soil


crushed dry leaves

dark gravel

light gravel

small pebbles

dry or crushed cement powder

plaster of Paris powder



small macaroni or crushed noodles

instant coffee


dried beans or lentils

hot chocolate powder

unpopped popcorn

crushed cereal

Put each ingredient into a separate cup and divide the cups into two categories, light and dark. (Put the flour, the light soil, the popcorn, and the sand on one side, for example, and all the dark ingredients on the other side.) Make sure the jar’s label has been removed (and the glue that was attaching the label as well), and that it is dry. The taller the jar, the more strata will be visible.

One by one, gently pour about a quarter-cup of each ingredient into the jar, alternating between light and dark. Do not tilt or shake the jar while you are filling it up. Make each layer between half an inch (12 mm) and an inch (25 mm) thick. If the top of the layer is irregular when you first pour it in, gently tap the side of the jar or smooth down the top with a finger or spoon. The layers need not be perfectly even. Try to use each ingredient at least once before starting over with a second layer of the first ingredient. Remember to alternate light, dark, light, dark.

When you are almost finished, fill up the jar to the very top with the last layer, so there is no empty space in the jar at all. Tightly screw on the jar lid. Now you have your own personal jar of strata. Inspect the different layers and imagine them full of fossils, crystals, and mysteries from the Earth’s past.

If there were fossils in your strata, where would the oldest fossils be found? Why? If a paleontologist compared fossils found on two different layers, what would the paleontologist be able to say about the fossil found on the lower layer?

Changing Environments

In most cities and states the weather is usually the same from one year to the next. In Phoenix, it is very hot every summer. In Minnesota, it snows every winter. Weather patterns pretty much stay the same. At least they seem to during the space of a single lifetime.

Over long periods of time, however, the Earth’s climate and environment have gone through many, many changes. Long ago, the Sahara Desert used to be covered with plants. Hawaii wasn’t even an island—it was under water. During the Ice Ages, much of Europe and North America were buried in ice. Throughout Earth’s history, its climate has shifted back and forth many times in many different ways. It’s even happening right now; the whole planet is getting warmer and warmer every year. Meteorologists predict that in a hundred years, the weather around the United States (and elsewhere) will be quite different than it is today.

Darwin knew that changing environments were an important element in his theory. Every time an environment shifts, the organisms in that environment must adapt to survive.

Evolution Through Natural Selection:
Darwin’s Theory Explained

Darwin spent years thinking about variation, heritability, overpopulation, the age of the Earth, and changing environments. He was trying to understand the origin of animal species. One day, the final piece of the puzzle clicked into place.

This was his brilliant insight: Every type of animal produces far more offspring than can survive. Most baby animals die before growing up. If not, the world would long ago have become overrun with animals. How do they die? Some are eaten by predators. Others starve to death. Others die of disease. Some grow to adulthood but can’t find a mate and never have any offspring. Only a few actually succeed in growing up and reproducing.

But why do some die and others survive? What’s so special about the survivors? Are they just the lucky ones? The answer, Darwin realized, lay in the variation among members of the species. Not all animals in any species are exactly the same. Those animals with some features that helped them avoid predators, get food, or find mates more successfully tended to survive longer than their brothers and sisters who lacked those features. Only the animals best adapted to their environment would survive long enough to grow up. Those animals that were weak or slow or foolish would tend to be the first ones to die. Darwin called this natural selection, but people often like to call it survival of the fittest.

The few surviving animals would reach maturity and have offspring. Because of heritability, their offspring would tend to resemble the well-adapted parents. Since the parents were generally the ones with the most useful features, they would pass those features on to their offspring. This way, all the harmful variations would die out, but the useful variations would be passed down and spread. Darwin’s term for this was descent with modification.

But what if the animals’ environment changed? The features that helped survival wouldn’t necessarily remain the same. As generations passed, animals with new and different variations would be the ones surviving and passing their traits on to their children. The more the environment changed, the more the species would have to change to survive in it.

Darwin realized that with enough time, an animal species could accumulate so many changes that it would no longer resemble the original species from which it descended. He called this process transmutation through natural selection. All that was needed to turn one species into another was time—countless generations of animals changing little by little as they adapted to their shifting environments. And his own investigations had shown him that the Earth was indeed old enough for evolution to explain the existence of every single living thing Darwin felt that all people, all animals, and even all plants were related to each other. At some point in the distant past a microscopic living organism first appeared, and all life forms on Earth were descended from that one tiny creature.

So here’s Darwin’s theory of evolution in a nutshell:

1. Any group or population of organisms contains variations; not all members of the group are identical.

2. Variations are passed along from parents to offspring through heredity.

3. The natural overabundance of offspring leads to a constant struggle for survival in any population.

4. Individual organisms with variations that help them survive and reproduce tend to live longer and have more offspring than organisms with less useful features.

5. The offspring of the survivors inherit the useful variations, and the same process happens with every new generation until the variations become common features.

6. As environments change, the organisms within the environments will adapt and change to the new living conditions.

7. Over long periods of time, each species of organism can accumulate so many changes that it becomes a new species, similar to but distinctly different from the original species.

8. All species on Earth have arisen this way and are thus all related.

Is That Everything I Need to Know About Evolution?

There’s more to evolution than what’s been discussed so far; biologists happily spend their whole lives studying it. Often, the more people learn about evolution, the more questions they have. To get you started, here are answers to some of the most common questions about evolutionary theory.

Does evolution really make animals change shape? Can I see it happen? That would be exciting, but unfortunately the answer is no. Evolution is not like a science-fiction film with special effects showing an alien creature growing a new head. Given enough time, evolution can make a species change shape, but not an individual animal. Every plant, animal, and person remains the same throughout its whole life. Groups evolve, not individuals. You’ll never be able to see a fish grow legs and start to walk; evolution doesn’t work that way. What evolution does is control what percentage of a group’s individuals possess a certain trait or feature.

Does evolution always happen to every species? Or do some animals never change? You might think from the description of evolution that natural selection is always working to bring about changes in species. But in reality most of the time natural selection prevents evolution from happening. Most of the variations and new features that might arise in organisms are not helpful at all, because evolution has already been going on or a very long time. Every species has already adapted to its environment as best as it can. Just about any change to a species would end up hurting it. Natural selection is continuously “weeding out” those variations that make an organism less adapted to its environment. Natural selection usually leads to evolutionary changes only if a species’ environment and living conditions are shifting. In many cases, animals and plants that live in a stable environment hardly evolve at all. Horseshoe crabs are a famous example. They’re fairly common on beaches around the world today. But archaeologists have found fossils of horseshoe crabs that look exactly like modern horseshoe crabs—except that the fossils are over 200 million years old. Horseshoe crabs have not evolved one bit in all that time because their environment—shorelines and beaches—hasn’t changed much either.

Is evolution the same thing as “progress”? Not necessarily. During the Industrial Revolution and the Victorian era, people thought that history was always progressing forward, that life got better and more advanced every day. So they naturally assumed that evolution worked the same way. It seemed that life on Earth had started as a tiny organism and had progressed upward through evolutionary changes to become the complex and superior creatures known as human beings. Yet Darwin showed that evolution does not always imply advancing toward more complicated or larger forms. Many animal species a hundred thousand years ago were larger than they are today; changes in climate made them evolve downward to become smaller. Other species, such as the peppered moth, evolve sideways (by changing color) but do not become any more or less advanced. Species merely adapt to their current environments. But that doesn’t mean they’re getting “better.”


People used to think that the transmutation of species took such a long time that it could never be directly observed. But sometimes we can actually see natural selection happen in nature over the span of just a few years. Darwin did not know it at the time, but an example of rapid evolution was happening in England during his lifetime. He would have been overjoyed if he had been able to observe it himself.

In northern England lives a type of insect called the peppered moth, whose wings are speckled with white and black spots. These moths prefer to rest on trees that have light-colored bark and whitish lichen growing on them. The local birds love the taste of these moths and eat them whenever they can. But the moths’ wings serve as camouflage; the speckled white-and-black coloration blends in with the bark and lichen, making them hard to notice.

At the beginning of the nineteenth century most of these moths had lighter colored wings with more white speckles than dark speckles. A small percentage liked to rest on darker trees and so had darker wings. But as the Industrial Revolution progressed, the factories of northern England spewed so much coal smoke into the air that the pollution not only killed the lichen but also covered the trees in soot. The moths’ environment changed. Now, when the lighter winged moths landed on the darkened trees, the birds could easily see and eat them. Only the darker winged moths remained camouflaged. They avoided being eaten by the birds and survived to have offspring that inherited their darker wings. Little by little, the number of moths with darker wings started to grow. Naturalists carefully studied peppered moths for years, and by 1900 they counted that 98 percent of the moths had dark-speckled wings! Most of the light-winged moths had been eaten and had not reproduced more of their kind. Transmutation through natural selection had been directly observed just a few miles from where Darwin was born.

The story of the moths is not over. Starting in the 1950s, England passed strong new air-pollution laws that limited the amount of exhaust coming from factories. By the 1990s most of the pollution had been eliminated. As a result, lichen grew back on the trees and the light-colored bark was again visible. Now the situation was reversed. The dark moths were plainly visible against the light background, and the birds ate them. But the few remaining light moths blended into the background, and they survived. Accordingly, the moths have evolved back to the way they were before—now most of them are light-colored again!

Are animals and plants really “perfect” in their design?
William Paley’s Divine Watchmaker argument relied on a basic assumption that all animals were “perfect,” intentionally designed like a watch to have all the right parts in all the right places. But Darwin and other naturalists discovered this was far from true. Animals often have weaknesses and deficiencies that could easily have been improved upon or eliminated if someone had designed them from scratch. Many animals have vestigial organs, body parts that don’t work and for which the animal has no use. Various kinds of snakes, for example, have leg bones. Why would God give snakes leg bones if they have no legs? Evolutionists will tell you that snakes evolved from earlier reptiles that did have legs—legs that slowly disappeared as the species changed. The external legs disappeared, that is; the useless leg bones continued to exist inside the snakes’ bodies. And if every species was “perfect,” then why don’t all animals have the best possible features: flawless vision and hearing, strong and fast legs, big brains, sharp teeth, and so on? Most don’t, because each species is just a hodge-podge of adaptations. Animals aren’t “designed” to be any way at all; they’re just an accumulation of evolutionary changes, some of which no longer serve any purpose.

Where Are the Missing Links?

Ever since Darwin’s day, critics of evolution have pointed out the absence of what have become known as “missing links.” (Scientists prefer to call them “transformational forms.”) If, as the zoologists claim, bats evolved from mouselike rodents, then where are the fossils of the creatures that were halfway in-between—a mouse with partial bat wings? None has ever been found. If there’s no evidence of transitional forms between two species, then how can we be so sure that evolution really happened?

Here are five good answers to that question.

1. Missing links do exist. Difficult as it may be to visualize, all modern birds are the descendants of prehistoric dinosaurs. Scientists have uncovered several fossils of the missing link between dinosaurs and birds, a transitional form called Archaeopteryx that looked like a flying lizard with feathers. They’ve also found many bones and fossils of transitional forms between ancient primates and modern apes and humans, both of which are descended from the same ancestors. Many other transitional forms in the evolution of horses and reptiles have also been found.

2. At least 99.99 percent of all the fossils in the world have not yet been discovered. They’re not easy to find! But paleontologists are searching for them every day, all over the world. So we haven’t found all the missing links … yet.

3. Only in the rarest of circumstances do animal remains become fossilized to begin with. True, scientists have not found the fossils of most transitional forms, but neither have they found the fossils of most “stable forms” either. The fossils may never have been created in the first place. Unless the conditions are just right for creating fossils, animal remains and bones will quickly disintegrate and disappear. Since transitional forms probably occurred under changing environmental conditions, it’s unlikely that their skeletons would be preserved undisturbed for millions of years.

4. Evolution does not happen at a consistent rate all the time. Most plants and animals will remain in the same environment for extremely long periods—millions of years, in some cases. As long as their environment stays the same, the animals won’t evolve very much, if at all. But when organisms are forced into a new environment, they must adapt quickly to survive. In a relatively short span of time (perhaps as little as 100,000 or even 10,000 years, which is like the blink of an eye in geological terms) a species could radically evolve, passing through many transitional forms. When it reaches a form that is best adapted to its new environment, that species will remain stable and essentially stop evolving for a long time again. This stop-and-start aspect of evolution is called punctuated equilibrium, because stable, perfectly balanced ecosystems (equilibrium) are occasionally interrupted (punctuated) by rapid change. As a result, almost all fossils are laid down during times when species aren’t changing, which is why transitional forms are rarely found.

5. Many top scientists answer the question in a completely different way: Every fossil ever found is a transitional form! All organisms, living or dead, are transitional forms from one species to another. It just depends on how you look at it. The animals of today could be considered transitional forms between their ancient ancestors and the unknown creatures into which their descendants will evolve far in the future. Maybe human beings will one day be thought of as the missing link!

• What is a “hopeful monster”?
Darwin was careful to point out that evolution does not happen in sudden jumps from one generation to the next, but rather in small steps. It’s extremely unlikely, for example, that some long-ago horse just happened to be born with black-and-white stripes, and that all modern zebras are descended from this one freakish striped horse. These freaks of nature were later called hopeful monsters. (Deformed and freakish animals are born every now and then, but their deformities almost always hurt rather than help their chances for survival.) Many people in Darwin’s era mistakenly thought that evolution required these “hopeful monsters” to work, an idea which was ridiculed as being impossible. As a result, Darwin worked hard to show that evolutionary changes happen very gradually and that his theory did not depend on the existence of freaks.

Natural Selection: A Closer View

Natural selection happens in many different ways. Animals have evolved countless strategies to find food, avoid being eaten by predators, attract mates, and survive all kinds of dangerous situations. Any trait that allows an animal to survive and reproduce is “chosen” by natural selection because the animals with that trait will pass it on to their offspring. These are just some of the fascinating adaptations that various animals have developed through natural selection.


Camouflage— markings that help an animal blend into the background—is one of the most common adaptations in nature. It’s the easiest way to avoid being seen by predators. (Remember the peppered moth?) Green tree frogs are barely noticed when they’re sitting on green leaves. Some animals change their colors according to the seasonal changes in their habitat. Jackrabbits are brown in the summer, making them hard to see against brown leaves and soil; in winter, their fur changes to pure white so that they’re camouflaged against the snow. Chameleons don’t have to wait for a new season. These lizards can change their skin color in seconds to match any color of their surroundings.

Predators also use camouflage to keep a low profile while hunting. The golden brown color of a lion’s fur is the same color of the dry grass where it hides while stalking prey. A bright pink lion would have a lot of trouble sneaking up on its victims!

Activity: Camouflage Egg Hunt

In the natural world, predators are always looking for something to eat. The easiest way to escape them is to blend into the background so they don’t notice you. Animals that are camouflaged have the same color and patterns as the environment around them. A predator will generally notice, catch, and eat only the most easily captured prey; after its belly is full, there is no need to keep hunting. This activity will demonstrate how the principle of camouflage can help organisms survive.

What you need

1 dozen eggs

stove and pot

a set of colored felt pens, or crayons

a friend (or relative)

pencil and paper

Ask an adult to hard boil a dozen eggs for you. Once the eggs have boiled for seven or eight minutes, cool them down by running cold water over them in the sink or placing them in the refrigerator.

Put all twelve eggs back in the carton and bring them, along with a friend, outside to a natural area with grass, dirt, bushes, and other plants. Your backyard or front yard is the best place for this activity but a park is fine too. Bring a set of colored felt pens—make sure to have a selection of greens and browns—or crayons (pens work better on eggs) and a pencil and paper.

Sit down in a comfortable spot. Look at the surrounding environment and choose pens that match the colors of the plants and other features around you. You and your friend should then take three eggs each and, one by one, draw camouflage designs on them. Use different colored pens to match the shadows and stripes and other patterns you see. Think about where you might be placing these eggs when deciding how to camouflage them. If you are going to place them in the grass, use a variety of greens. If you are going to place them in a bed of dried leaves, use browns and grays. Remember to leave six eggs plain white, completely uncamouflaged.

Once you’re done coloring, ask your friend to close his or her eyes while you place all twelve eggs around the yard or park. For the experiment to work properly, the white and colored eggs should be placed in similar locations—you shouldn’t hide all the camouflaged eggs in the most difficult spots while leaving the uncamouflaged eggs out in the open. For every white egg you place in the grass, place a camouflaged egg in the grass. After the eggs have been hidden, ask you friend to look around and pick up the first six eggs he or she finds. After six, have your friend stop looking and bring all six back to you.

On one half of your paper write “Camouflaged,” and on the other half write “Uncamouflaged.” Make a mark under each heading for each egg found.

If the color of an egg’s shell didn’t make any difference to your friend, the “predator,” he or she should find, on average, just as many camouflaged eggs as white eggs: three each. But how many of each kind did your friend actually find?

Retrieve the remaining six eggs, then repeat the experiment, but this time have your friend hide the eggs while you close your eyes and then search. Write down the data from the new trial. Repeat the experiment several more times until you begin to see a pattern in the totals. Did the coloring on the eggs help or hurt their chances of being detected by a predator?


Some animals use mimicry—imitating or pretending to be something else—to help them survive. Certain butterflies and moths have spots on their wings that look like scary eyes; from a distance they look like the eyes of a large predator, so birds are afraid to eat these butterflies. The “walking stick” is an insect that looks so much like a twig that you can scarcely tell it apart from the real thing, even up close.


This one’s obvious: The faster an animal can run, the better it can escape from whatever’s chasing it. Most animals have evolved to run as fast as they possibly can, considering their size, body shape, and environment. Predators have to go fast too, or they’ll never catch their prey. A cheetah chasing a gazelle is a sight to behold!


Animals that are slow and easy to catch sometimes develop ways of tricking their enemies into going away. Opossums and certain kinds of snakes will occasionally pretend to be dead, hoping that whatever is fighting them will lose interest and leave them alone.


One way to avoid being eaten is to be hard to eat. Armadillos have tough, bony plates covering their bodies; when they curl up into a ball, there’s no way for a predator like a wolf to get inside. Porcupines and hedgehogs are protected by hundreds of dangerous, sharp spines.


If something’s poisonous (toxic) or tastes bad, then predators will quickly learn that it’s not good to eat. This strategy is most common among plants, insects, and fish.

Acute Perception

This too is one of the most common adaptations in nature. The better any animal can hear, see, or smell, the better it can hunt for prey or detect predators before they get too close. Some animals have developed all kinds of amazing perception systems that we humans don’t have. Dolphins and bats use sonar (bouncing ultrasonic waves off prey) to hunt. Scorpions and elephants can detect vibrations in the ground. Owls and ocelots have acute night vision and can see in almost total darkness. Even dogs can hear sounds that humans can’t hear.

Dietary Diversity

Animals have acquired all kinds of adaptations that allow them to eat a wide variety of foods. Giraffes, of course, have evolved long necks to reach leaves on the tops of tall trees. Cows have four stomachs that allow them to eat and digest grass, which most animals cannot digest. Some animals have developed an immunity to poison, which allows them to eat other animals that have evolved to be toxic!

Even plants have evolved unique strategies for getting food. Venus flytraps catch insects in their leaves and dissolve them with special digestive fluids. A sundew snares bugs on its sticky hairs; the plant then swallows up its prey and digests it. Darwin was so fascinated by these carnivorous plants that he spent years researching them.

Choosing Partners

If camouflage is so important for survival, then why are some animals brightly colored? How can natural selection explain something as flamboyant, beautiful, and seemingly useless as a peacock’s tail? Peacocks with smaller, duller tails would be less visible to predators, so it seems that they would be more likely to survive and that colorful tails should never have evolved. Yet they have. Why?

The answer is a form of natural selection called sexual selection. While it is not as important as other aspects of natural selection, it does account for many of the features that otherwise seem to have no evolutionary explanation.

Darwin’s theory of sexual selection states that an animal must do more than merely stay alive to pass its traits on to later generations—it must also have offspring. And the only way to have offspring is to mate with a partner. So evolution will tend to favor those animals that are best at attracting mates. Unattractive animals will tend to have fewer offspring, and their features will die out.

But what determines “attractive”? This is a mystery no one has yet figured out. Whatever the reason, we do know that many animals regard certain features as especially appealing. Peahens (female peacocks) think that the peacocks with the flashiest tails are especially handsome. As a result, the most colorful peacocks have the most success finding partners, have the most offspring, and pass on the flashy-tail genes to the next generation. Over the years, the peacock species thus evolved to have colorful feathers. Dull peacocks may have had more success avoiding predators, but they left fewer offspring.

Activity: The Benefits of Beauty

According to the theory of sexual selection, being attractive is sometimes more important than being strong or clever. Birds with big flashy tails attract more mates—but they also can attract more predators. Is it really worthwhile to have an attractive feature if it only makes you more likely to be eaten? This activity shows how visually striking traits can become common in a species even if they seem to hurt chances for survival.

What you need

8 nickels (or any other small, plain objects, such as buttons, erasers, macaroni noodles, checkers, etc.)

40 pennies (or any other small, pretty objects, such as marbles, candies, plastic toys, hair ornaments, etc.)

This activity is a simple version of a life-simulation game that scientists use to model how evolution works. The game will show how certain features can spread throughout a population over several generations.

In this game, the objects all represent male members of the same species—a plain-looking kind of bird we’ll call the Dum-Dum Bird. The nickels are the standard form of the species—bland and unremarkable, having evolved to avoid predators by blending into the background. But a new variation in the Dum-Dum Bird population has arisen—a few of the males now have some bright red feathers. This new variation is represented by the pennies.

The female Dum-Dum Birds are attracted to the males with red feathers. But the color also draws the attention of the foxes—the predators that like to eat Dum-Dum Birds whenever they can.

The rules

At the start, 80 percent of the birds are plain (nickels), and 20 percent have red feathers (pennies). With each passing generation, only onefourth of the plain birds get eaten by foxes; but half of the red birds get eaten. On the other hand, each plain bird will be lucky to find one partner willing ever to accept him, so he will leave just one male offspring over his entire lifespan. The red birds, however, are so popular with the female birds that each will leave on average four male offspring over his entire lifespan. In both cases, the offspring will inherit the same coloration of their fathers.

How to play

Place 10 coins in a row: 8 nickels and 2 pennies. This is your first generation of 80 percent plain birds and 20 percent red birds. Now, apply the rules described above to this generation (and all later generations). Onefourth of the plain birds will be eaten by foxes, so remove one-fourth of the nickels: 2 nickels. Half of the red birds will be eaten, so remove half of the pennies: 1 penny. You’re left with 6 plain birds and 1 red bird.

Now it’s time to make the next generation. Each plain bird will leave only one plain male descendant, so slide all 6 nickels down a few inches.

But each red bird will leave 4 red male offspring, so place 4 pennies adjacent to the nickels in the new row.

You’re now on the second generation. Notice how the population has changed: Even though a greater percentage of red birds was eaten before they could leave offspring, their mating success has paid off. In the second generation the plain birds are down to 60 percent of the population, and the red birds are up to 40 percent.

Repeat the process for three more generations. Round all numbers up: One-fourth of 6 will be 1.5, which you should round up to 2. What happens to the population of the Dum-Dum Birds? At the end of the game, what percentage of the birds will be plain (nickels), and what percentage will have red feathers (pennies)?

This is how sexual selection works: Species can evolve to acquire appealing but harmful adaptations too, because reproductive success is just as important as survival. Beauty has its benefits!

The same principle holds true with many other animals and features. The females of some bird species show a preference for male birds that do a mating dance. Male frigate birds and hummingbirds flap and fly and chirp in amazing displays that can last for hours. Sexual selection has preserved these seemingly strange behaviors.

Other behaviors related to sexual selection are not about impressing the females: They’re about intimidating rival males. Bull elephant seals become extremely aggressive and violent around mating season. The bossiest males get more partners not because the females like them any better but because they’ve scared away all the other males.

More Than Just an Idea

It’s not hard to imagine why it took Darwin twenty years to write the Origin of Species, his book about evolution. The basic idea was clear to him, but there were so many details to work out, so many questions that had to be answered. In fact, he never felt that he had properly explained his theory. To Darwin, Origin was just a brief summary of the arguments for evolution. Before events forced him to describe his theory as quickly as possible, he had been planning to write a book about evolution that was ten times as long!

He also wanted to make sure his idea stood up to any possible criticism. He spent years accumulating evidence and facts to back up his theory. Often, he made the investigations and confirmed the facts himself. It was essential that his theory was scientifically rigorous, or confirmed by scientific observations. This was a new way of doing things in natural history. The earlier evolutionary thinkers were just that—only thinkers. Their theories had just been speculations. No one really knew whether or not their guesses were correct. Darwin, on the other hand, wanted to make sure that evolution was the only possible explanation for all the factual evidence he had collected from geology, anatomy, paleontology, and biology.

Those aren’t the only reasons Darwin was reluctant to go public with his theory. He knew from the beginning how controversial his idea would be. Few people had ever before dared to imply that humans were related to apes. But he hated controversy. He never argued with anyone, and the thought of speaking in public frightened him. Like any proper Victorian gentleman, he wanted to avoid scandal at all costs.

Yet he was a scientist, with a duty to reveal the truth as he knew it. He was caught in a terrible dilemma. In the end, he felt he had no choice; he published his theory, no matter what. It was a brave thing to do.

Sure enough, the response to Origin was immediate and explosive. Speakers insulted him. Preachers condemned him in their sermons. All of society was scandalized. “How dare this man question the unique and lofty status of the human race,” they demanded. “Is he suggesting that we are descended from monkeys? How dare he say we are not created in God’s image! This book is an insult to the Bible,” they said.

Fearing just these kinds of attacks, Darwin purposely never mentioned in the Origin of Species that human beings were the result of evolution as well. But it didn’t matter. Everyone jumped to that conclusion. Philosophers began to ask questions that Darwin could not answer. If, as everyone agrees, each human being has a soul, then when did we as a species acquire our souls? As far as anyone knew, animals didn’t have souls, but if evolution is true, then long ago we were animals just like any other. Was there some moment in history when an intelligent monkey first acquired a soul and became a human being?

Darwin did not realize it at the time, but he changed forever the way the human race sees itself and the world. And he changed how scientists search for the truth.

Chapter Eight Endnotes

1. CSICOP: The Committee for the Scientific Investigation of Claims Of the Paranormal.

2. Quoted in Dragons of Eden by Carl Sagan (New York: Random House, 1977).

3. Paul Kurtz, The Courage to Become (Westport, CT: Praeger/Greenwood, 1997).

4. Quoted in Summer for the Gods by Edward J. Larson (Boston: Harvard University Press, 1998).

5. Richard Dawkins, Unweaving the Rainbow (New York: Houghton Mifflin, 1998).

6. Judith Stone, “Light Elements,” Discover (July 1989).

Additional Resources


• McNulty, Faith. How Whales Walked into the Sea. Scholastic Press, 1999. Traces the evolution of whales from wolflike land mammals over the course of twenty million years. The fossil intermediaries that filled in the blanks in whale evolution are brand-spanking new discoveries from the 1990s, so this fascinating book has the distinction of being well ahead of many high school and college textbooks. Each two-page spread takes a single, easy-to-follow evolutionary step, providing hypotheses for how natural selection may have spurred the development of each new form. A book likely to send parents’ voices trailing off in wonder as they are reminded just how lovely and compelling the evolutionary process is. Ages 6–12.

• McCutcheon, Marc. The Beast in You!—Activities & Questions to Explore Evolution. Williamson, 1999. A marvelous, colorful, engaging look at our animal nature and ancestry, filled with activities and illustrations to introduce basic evolutionary concepts. A one-page nod to the question of faith vs. science, essentially embracing Steve Gould’s idea of two mutually exclusive magesteria (“The Bible isn’t a scientific textbook—it was never meant to be”). Ages 8–12.

• Lawson, Kristan. Darwin and Evolution for Kids—His Life and Ideas with 21 Activities. Chicago Review Press, 2003. This is the book for kids who are finally ready to learn how evolution works and the amazing story of its development over centuries, its unlikely nineteenth century expositor, and the sixty-year torrent of outrage, critique, and discovery that followed the 1859 publication of the Origin. At the end, your 12-year-old will know evolution in greater depth and detail than most adults. Ages 12 and up. [N.B. The essay “The Idea That Changed the World” in the current book is reprinted from Darwin and Evolution for Kids.]

• Peters, Lisa Westerberg. Our Family Tree: An Evolution Story, Harcourt Children’s, 2003. Ages 4–9.

• Gamlin, Linda. Eyewitness: Evolution, DK Children, 2000. Ages 10–14.

• Pfeffer, Wendy. A Log’s Life, Simon and Schuster Children’s, 1997. Winner of the Giverny Award for Best Children’s Science Picture Book, this description of the life cycle of a tree is just one in a long line of outstanding children’s science books by Wendy Pfeffer. Ages 4–8.

• Couper, Heather, with Nigel Henbest. Big Bang—The Story of the Universe. Dorling Kindersley, 1997. A gorgeously illustrated explanation of the “Big Bang” theory of the origin of the universe. May be a bit challenging, depending on a child’s prior exposure to science vocabulary and ideas, but worth the effort. Ages 12–18.

• Bailey, Jacqui. The Birth of the Earth from The Cartoon History of the Earth series, Kids Can Press, 2001. An inventive comic-book style presentation of good science. Ages 9–12.


Cellular Visions: The Inner Life of a Cell. A captivating, award-winning animated short created by XVIVO Scientific Animation to show the incredible complexity and beauty of life at the cellular level. A three-minute version of the animation is available on many websites—search for “Cellular Visions” or “The Inner Life of a Cell.” Ages 6 and up.

Wonders of the Universe Video Series (Ambrose Video, 1996). Thirteen half-hour segments exploring different aspects of the cosmos. Animation quality somewhat dated and varies in pace and engagement—but when it’s good, it’s very, very good. Ages 10 and up.

Walking with Cavemen. BBC, 2003. A fascinating attempt to condense human evolution into a graspable storyline with actors in epic layers of latex makeup portraying the various species along the way. An impressive stab at a subject that is devilishly hard to depict. Ages 8 and up, though clearly pitched to adult viewers.

Walking with Dinosaurs. BBC, 1999. This time the medium is the cutting edge of computer animation. The result is the most realistic depiction ever of life in the age of dinosaurs. An astonishing technical and artistic feat. Ages 10 and up, due mostly to some graphic scenes of dino-on-dino gore. Kids as young as 6 can watch and divert their eyes when the music says.

Intimate Universe: The Human Body. BBC Warner, 1998. Easily among the most compelling science documentaries ever made, this four-volume set explores all phases of human development from conception through birth, puberty, pregnancy, aging, and death, using a combination of endoscopic camera work and cutting-edge animation to take the viewer places that—believe you me—you never thought you’d go. Entirely wonder-inducing and conversation-starting. Ages 6 and up.

Evolution, PBS series produced by WGBH Boston and Clear Blue Sky Productions, 2001. Outstanding, high-quality documentary series available in VHS and DVD. Should be in every public library.


• Inquiring Minds ( The educational wing of CSICOP (The Committee for the Scientific Investigation Of Claims (*deep inhale*) of the Paranormal. A relatively young venture, still building its offerings, but off to a grand start with classroom curricula, activities, and links.

• National Geographic Xpeditions ( An extraordinary collection of activities for home or classroom related to seasons, ocean geography, astronomy, natural disasters, biodiversity, migration, and much more.

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