'Four Fifths A Grizzly' Is Chadwick's Reminder That Wildness Resides In Our DNA

Bears especially are loaded with questions.  

When he returned to western North America from writing assignments around the world, he continued to watch grizzlies. “I didn’t think much about why. Although I hoped to understand more about their behavior and the obstacles to their survival, the main draw for me was witnessing their indomitably wild spirit—one that, after more than a century of persecution, still reared up to say the hell with you two-leggeds and your whole tamed-down, fenced-in, crowded-up version of progress.”  

As intelligent, playful, curious, unpredictable, dominant omnivores, it’s no wonder that humans overlap with bears, genetically. “The number of genes we share with a grizzly obviously doesn’t mean that we look and act 80 to 90 percent like even a realistic-size one. Every mammal needs to regulate cell metabolism, oxidize sugars, generate electrical impulses, coordinate packets of muscles, blink, chew, move, make milk, filter waste products, fight off pathogens, get plenty of warm blood to the brain, and we all do it with the same molecular tools. Even the egg-laying, duck-billed, barely-a-mammal platypus shares about 82 percent of its genes with us.” 

Not only that, we’re part baker’s yeast, too.   

  

At the same time, being more closely related to avocados, ants, and aardvarks than most people suspect “doesn’t dilute our stature as humans but instead increases it manyfold. It renders us more than human,” he writes. “This is our deep heritage, an old, enduring kinship as big as the living world.”

Chadwick clearly hasn't lost his childhood curiosity. We are awed by association when he steps outside for a midnight pee, looks skyward, and takes “a sudden dunk into the universe… a little open-mouthed speck of life within a glittering immensity—marveling that I should exist.”

It all started with his father’s microscope, which may be why—after writing books on several of the world’s most charismatic mammals—the author returns to the tiny and microscopic critters that tie us all together. The more he traveled, the more he absorbed a core fact about life on Earth: most of it is invisible.

Close to a thousand different species of microbes live in your mouth; and more than 20 trillion individual microbes inhabit your body. “The littlest critters perform some of the most basic functions: Diatoms, micro-algae, and a single cyanobacterium genus (superabundant in seawater and capable of photosynthesis) produce about half the oxygen in our atmosphere.” 

Earth is essentially the planet of the microbes—viruses included, such that 8 percent of our genome is viral material retained from infections in our ancestors. We need exposure to those bugs in order to build our immunities, and children with robust immune systems are at lower risk for the most common form of childhood leukemia. The best time for kids to play in the dirt is as soon as they learn to crawl. 

“Taken together,” he notes, “the invisible multitudes on and in us redefine every person as a kind of compound creature, an organism that is in reality a combination of organisms interwoven in more ways than we have yet found words to acknowledge. I relate to the world in an ‘I, me, mine’ frame of mind but in reality, I function as an ‘us.’ Everybody does.” 

Perhaps there really is a scientific angle to the Buddhist puzzle that asks that the student to identify where the “I” that we steadfastly cling to actually exists.

Bacteria, mycorrhizae, soil organisms, termites and other bugs big and small form the essential web of support for, well, everything else. Dung beetles, by Chadwick’s reckoning, deserve keystone status, considering the variety of roles they play and the multiple symbionts toiling along inside them. Indeed, most species can best be described as holobionts—assemblages of partners. “Biologists have made great strides in analyses… splitting nature into more precise categories. Perhaps further progress lies in the direction of synthesis—putting the pieces together, the better to understand how they function as a whole…. Each of us is by nature a collaboration or collective—a joint venture—of fellow Earthlings.”

The millions of species in existence represent the largest and most elaborate store of information on Earth. (One fifth of all the mammalian species are bats. Yet mammals make up just .005 of one percent of the total number of species.)  “What,” Chadwick asks, “are we doing with this treasure?” 

These organisms and their genomes comprise the miraculous but fading blueprint for our biodiverse planet. “We now qualify not only as the foremost threat to all kinds of other Earthly life, but also as the biggest obstacle to a secure tomorrow for ourselves.” Ultimately, the health of the countless biological beings around us, from enormous to miniscule, will directly shape our collective destiny. 

Who woulda thunk, for instance, that the strawberry—wild or cultivated—was such an evolutionary marvel. Designed to be eaten and savored, the fruit’s vitamin C, potassium, manganese, calcium and flavonoids promote the production of endorphins—natural opioids.  And it grows in symbiosis with a micro-menagerie of healthy bacteria, microbes, and mycorrhizae.

“There is far more to being human and more to the qualities we share with strawberries and all other multicellular creatures,” Chadwick writes. “Even the grandest tree consists of a webwork of fungi in symbiosis with a population of photosynthesizing cells (which in turn contain symbiotic bacteria in the form of chloroplasts and mitochondria).” He expands this description to include “the interdependent contents and connections that make up a large-scale community or ecosystem such as a forest, a savanna, or marsh. Is that exaggerating the definition of an organism, or sheer fantasy? Or is it an incentive to think about every aspect of nature as something greater and alive in more ways than we were able to make sense of before?”  

In a chapter titled “Kaboom,” Chadwick dives into population growth. “Every four or five days now, the planet has to provide room and sustenance for as many additional human beings as existed worldwide in 10,000 BC.” One consequence is that of every ten wild animals that roamed Earth as recently as 1970, only three stand in their place today. A full 60 percent of large herbivores and carnivores are currently considered to be threatened with extinction, and plants aren’t doin’ so well, either.  

Chadwick doesn’t hastily cast blame, considering that humans are acting on their own genetic imperative. “People are merely continuing to strive for more space and resources. It’s what species do…. No other creature does memes plus tools plus complex improvisation like modern Homo sapiens.”

There is hope. As we know from the study of island biogeography, remote islands are unique ecological time capsules, but are vulnerable to invasives and to introduced predators having their way with unwary prey. The 465,000-or-so oceanic islands comprise less than 6 percent of Earth’s total land area, yet are the locus of more than 60 percent of the known extinctions of the past 500 years. A selection of hands-on projects that Chadwick profiles, however, have restored islands to something resembling their pre-industrial (or pre-predator/invasive) state. One outfit, Island Conservation, has worked with partners to restore about 1,200 populations of 490 species and subspecies worldwide. Simple, practical, and inspiring.  

In the chapter on animal intelligence, “Crowboarding” (yes, if you’re guessing), the author avoids drifting too far into sociology, but “can’t help but notice a strengthening of the movement to treat fellow creatures more humanely. Though hardly new, the trend appears to be expanding in parallel with the coverage given animals in both popular media and social media.” 

The author brings us back to the Rockies through the Yellowstone to Yukon Initiative (Y2Y), the subject of an earlier book of his. Spanning 2,000 miles of the continent’s backbone, it is one of the most successfully conserved, largely-contiguous mountain ecosystems in the world, even though its collaborative efforts are still in the beginning stages.  

“Can humans and wildlife truly prosper together over time?” he asks. “Of course they could. The underlying issue has always been whether people with different backgrounds and interests can work well enough with one another to make a better level of coexistence with nature possible. In a way, Y2Y is an experiment to find out how much better that level could be.”

Note to educators: This title works as a well-cited, readable companion to a high school biology textbook. (The photos alone make this volume a treasure.) It reaches from microbiology to astronomy—from Archaea and the building blocks of biology, to suggesting that Earthly life may have been seeded by extra-terrestrial microbes (panspermia). As a homework assignment, were I younger, Four-Fifths would have been an enjoyable complement to the chore of parsing mitosis and meiosis. I just might have become the informed naturalist that the planet needs more of.  

That’s the best sort of science education: being escorted on a mesmerizing personal journey into the greater ecosphere—which includes us—and coming out the other side with an unshakable sense of wonder at the planet. Perhaps we can all be guided by this book’s adapted golden rule: Do unto ecosystems as you would have them do unto you. “Nurture, sustain health, allow to flourish.”