検索キーワード： "metamorphosis" 科学・工学

“How many creatures walking on this earth / Have their first being in another form?” the Roman poet Ovid asked two thousand years ago. He could not have known the full extent of the truth: today, biologists estimate a stunning three-quarters of all animal species on Earth undergo some form of metamorphosis. But why do tadpoles transform into frogs, caterpillars into butterflies, elvers into eels, immortal jellyfish from sea sprigs to medusae and back again, growing younger and younger in frigid ocean depths?

We’ve all heard the story about waking up as a cockroach—but what if a crisis turned you into a clam? After the dissolution of her marriage, a writer is transformed into a “clam” via typo after her mother keeps texting her to “clam down.” The funny if unhelpful command forces her to ask what it means to “clam down”—to retreat, hide, close up, and stay silent. Idiomatically, we are said to “clam up” when we can’t speak, and to “come out of our shell” when we reemerge, transformed.

An artist turned naturalist known for her botanical illustrations, Merian was born just 16 years after Galileo proclaimed that the Earth orbited the sun. But at the age of 50, she sailed from Europe to the New World on a solo scientific expedition to study insect metamorphosis—an unheard-of journey for any naturalist at that time, much less a woman.

For thousands of years, scientists, philosophers, and self-help gurus have wrestled with one of the basic conundrums of human life: Why do we do the things we do? Or, rather, why do we so often not do the things we want to do? In You're a Miracle (and a Pain in the Ass), McHargue addresses these issues. We like to think we’re in control of our thoughts and decisions, he writes, but science has shown that a host of competing impulses, emotions, and environmental factors are at play in every action we undertake.