Teaching Evolution: Three More Thoughts

Here’s a link to my post about the Evolution Treasure Hunt. I’ve kept thinking about all that, and my thoughts right now have been shaped partly by my father’s very last journey, in process as I write.

A Particular Kind of Walk through the World

Helen York on Adams HillNaturalist Bernd Heinrich now owns the old hill farm on Mount Blue’s shoulder, where one of my great-grandfathers tended cows and apple trees, and where my grandmother posed one Fourth of July for a photograph taken with the Kodak Brownie camera she’d been given by her students’ parents.

In one of his books, The Trees in My Forest, Heinrich explores the woods that took over my great-grandfather’s pastures. He describes an isolated apple tree, far from the old orchard. How did it get there? Did a bear carry and drop an apple, or deposit scat containing a seed?

Eventually, Heinrich describes a game he himself played, growing up with some of my grandmother’s cousins, another branch of Adamses. Each child skewered, on the end of a supple sapling, an apple too wormy to eat, and then, with a practiced flick of arm and hand, flung the apple as far as it could go.

They weren’t planting; they were playing. Some of the world can only be explained by play.

Elsewhere in the same book, chewing his way through observation after observation, Heinrich tackles another kind of mystery. Why do deciduous trees drop their leaves? He explains how expensive this is for the tree, to produce a new crop of leaves every year, like a manufacturer building a whole new set of factories—and then trashing them.

Here’s a piece of the answer: if the leaves were retained, in a place like Maine, they would hold snow and overload the branches, breaking them. Yes, I thought, remembering the destructiveness of unusually early autumn snowfalls, the sound of maple branches crashing to the ground.

evolution Lisa Westberg PetersDid someone design trees that would drop their leaves? My great-grandfather and my grandmother would have answered, resoundingly, yes: God designed and created every natural thing around us, chose all their shapes and functions. As a child, I believed that myself, sang hymns that said so. (I still sing them, with my parents’ and uncles’ and aunts’ voices–and the photographs on the top of my grandparents’ piano–vivid and treasured in my mind.)

As an adult, though, I have come to understand another explanation that seems to me equally wonderful. Mutations that led to leaf drop gave an edge toward survival and progeny. The mutation persisted, generation by generation, because it did something useful for the species.

Here’s the translation in my heart: letting go of all those leaves, all those creations, lets the tree live on.

If, like me, you feel the importance of evolution Steve Jenkinsan evidence-based, scientific understanding of how the world we see came to be—

if you want to share that with your students or children or just the many daily wandering-around versions of yourself, but the real texture of that understanding is still pretty fuzzy in your mind—

and if you have an allergy to abstractions, as I tend to—if abstractions just don’t stick to your ribs as well as specifics do—

you may want to read Bernd Heinrich, or other evolution-informed naturalist writers, who will take you on a very particular kind of walk through the world, noticing things and thinking through how they came to be like that, doing a steady series of experiments with bumblebees, ravens, squirrels, weeds; observing the tracks and traces of evolution in detail.

(If video works better for you, here’s a link to a brief video from the HHMI series called The Making of the Fittest. This one describes the effects of natural selection, as observed in the coloration of rock pocket mice in the American southwest. It’s short, vivid, and persuasive–and there are many more where it comes from.)

evolution Piero VenturaFor me, that kind of walk through the world is ultimately full of joy, true joy in the rich diversity and beauty of what works. When you can come to that joy in the reality of the world, whatever your religious beliefs may be, you will be part of our culture’s growing up, part of our species’ reach into clearer understanding. Teacher / scholar / student / parent / citizen—we’ll all be lucky to have you along on that voyage.

Squabbles in a Transitional Time

In so many places, evolution is minimized, or outright skipped, in elementary or middle school teaching of biology.

Even at the college level, some students do their own censoring. Here’s a piece by a professor at the University of Kentucky, who knows that some of his introductory biology students will storm out of the lecture hall and slam the door behind them, when they wake, in shock, to the news that evolution is the organizing principle of modern biology–not a minor topic that can be side-stepped, but the key to everything we know about the nature of life. It might have been better for them to hear some version of that sooner. Maybe when they were five. Or three.

Here’s another link, to a lecture by Kenneth Miller, cell biologist and faithful Catholic, who answers high school students’ questions about religion and science by affirming the powerful evidence for evolution, and at the same time expressing compassion for students’ confusion about how we define meaning in life.

evolution David Peters cAt my own very progressive school, parents of whom I am enormously fond turned to me and said, “But evolution is just a theory, right?”–misunderstanding the word theory to mean unproven and unreliable. But a scientific theory is a huge concept that makes sense of overwhelming evidence–not something less strong than a fact, but something held up by, and holding in a coherent whole, thousands upon thousands of facts.

Students I prized–exactly because they worked energetically to hold in one mind everything they were learning–asked, “But what about God? This is so different…”

Accepting religious teaching as scientific authority can put people of any age in a jam. My father, a biologist, told me a while back that an emotional and mental breakdown while he was in graduate school had been triggered largely by those conflicts.

Commitment to my students and their parents, and affection for them, encouraged me to keep thinking carefully, not about whether we would explore evolution–but about how. Still, now, I’m always looking for voices that honor the evidence for evolution and also explore ways we can all absorb it–because absorbing it is an unfinished task for my people (by which I mean all of us), and it’s not so easy to do.

“Go find a good children’s book…”

My mother, a retired children’s librarian, still says this to anyone who’ll listen. “To begin learning about almost anything, go find a good children’s book. A picture book, if possible.” I’ve illustrated this post with the covers of four children’s books that played important roles in my own effort to understand. You’ll find the bibliographic information down below, at the bottom of the post.

Eventually, I read Stephen Jay Gould, a selection of Darwin’s letters, an entire volume about the extinct arthropods called trilobites, book after book after book about human evolution. This winter I’ve been reading Bernd Heinrich’s latest book, The Homing Instinct.

I started, though, with picture books and other non-fiction for young readers. I knew that I would be in honorable company, a learner among learners, a voyager among voyagers.

Our Family Tree: An Evolution Story, by Lisa Westberg Peters with illustrations by Lauren Stringer. Harcourt, 2003.

Life on Earth: The Story of Evolution, by Steve Jenkins. Houghton Mifflin, 2002.

Darwin: Nature Reinterpreted, by Piero Ventura. Houghton Mifflin, 1995.

From the Beginning: The Story of Human Evolution, by David Peters. Morrow Junior, 1991.

The last two books listed work best for older children supported by adult fellow learners. They’re both out of print, which makes me sad–but I’ve just confirmed that they can be found used online.

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