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CA Mushrooms

Book Review

A Natural History of the Future

By Robb Dunn
2021, Basic Books
ISBN: 978-1-5416-1930-2
Hardcover; 306 pages
$30 USA, $38 Canada

Robb Dunn is an evolutionary biologist at North Carolina State University and an avid writer, regularly featured in National Geographic, Scientific American, New Scientist, Smithsonian magazine, etc., and has written several books. His research interests are quite diverse ranging from examining entire societies to individual organisms, and very often microbes. His professional homepage states that: “Most of the living world remains poorly or totally unknown. In my lab we study the species around us in our everyday lives, species we tend to think of us as well known. Most of those species are not well known and so there are many things to discover in your backyard, in your bedroom, or even on your roommate. Some days I work to study these species myself, bending down to figure out whether the fungus on my neighbor’s foot is a new species. […] I also write about the world around us, which is a chance to share the stories of the scientists who have devoted their lives to understanding species, organs, cells, genes or ecosystems that influence us every day.”

Natural History of the Future: What the Laws of Biology Tell Us About the Destiny of the Human Species shows that while we are focused on global climate change—and how it very well could be disastrous to all life on the planet—this should not be our only concern. More attention is needed on the myriad other ways humanity is affecting the living world. We didn’t get into this mess overnight; even if we could halt fossil fuel emissions tomorrow, we would still need to make some big changes.

Humans are just one species among millions on the planet, and yet we exert outsized control over conditions on Earth. As a result of ever better science and ingenuity, we have tamed rivers, harnessed the wind, felled entire forests, leveled mountains, and converted vast swaths of land to agriculture. But is this sustainable? Newer science tells us that it’s not. Science led us to discover just how evolution works; Darwin explained how, slowly, organisms “change” over time. Newer science shows it isn’t always so slow: many organisms, including agricultural pests and even human pathogens, can evolve in real time—outflanking our latest pesticides and antibiotics.

Humans are everywhere. According to Dunn, 32% of terrestrial vertebrate biomass on the planet is “composed of fleshy, human bodies;” domestic animals make up 65%. (That’s right: the remaining 3% is all the other vertebrates!) Also noted: humans now consume more than half the net primary production of photosynthesis of the entire planet—but at a serious cost. The miracle of modern agriculture has allowed the population of our species to swell, but has led to severe habitat loss for nearly all the other denizens of the planet—habitats that for millennia hosted birds, native plants, mammals, butterflies, bees, and other diverse life-forms. And many of these we, in turn, rely on for medicines, pollination, and food. It isn’t all depressing, though, Dunn takes a number of side journeys to explore organisms that have greatly benefitted as a result of human expansion. He points out that there are “hundreds, perhaps thousands, of pest and parasite species that live nowhere else” but our vast agricultural fields. And more are evolving all the time; the author estimates that more new species have evolved in our crops than on the Galápagos Islands. And the story is the same in cities too; many organisms go by the wayside as cities arise, but assuredly cities provide prime habitat to others. And it’s not just outside our urban walls, but inside too! Dunn estimates that “no fewer than a thousand animal species now live indoors.” Of course, I’m most fascinated by microbes—especially fungi—and Dunn gives them their due in this book as well.

Much of what this book is about is natural selection and how those forces don’t stop simply because one species is changing (and re-changing) the landscape and the ecology. And in each chapter, Dunn ticks off “laws” of biology that are at play keeping natural selection going. The only problem I had with the book, and it came up nearly every chapter, is that Dunn not only overuses the term “law,” he never defines it. It wasn’t all that long ago that I was a college biology professor and I have no recollection of many of these “laws” of Nature. I think many of Dunn’s laws are concepts and principles that sometimes are pretty well understood (other times not) and may explain how some systems in Nature function but they are not immutable laws. Furthermore, there were several places in the book where the author shows a lack of understanding of the topic being discussed. Noting how convergent evolution has led to similar forms among birds and mammals, for example, Dunn discusses (page 49) the seemingly fantastic “flightless bats” of New Zealand. While it’s well known that on islands many flying birds (and insects), over time, lose the ability to fly (it’s thought that flight becomes a hazard and is thus selected against), but this has not happened to the bats of New Zealand. (There are a couple of bat species there that spend far more time on the ground foraging and going about their business, than their cousins throughout the planet, but according to all literature they still spend at least half their time flying.) On the pervasiveness of plant parasites and pathogens (page 102), “researchers recently found plant parasites growing in gardens maintained by astronauts on the International Space Station. Plant parasites are already in space.” (The full chain of thought here is that pests are so good at doing what they do, they often precede their host’s next move, and were already in space, somewhere, prior to the arrival of plant hosts.) No, of course they are not already in space (since there are no plants to host them there); the parasites assuredly were carried to space with the plants, or growing material, or on the astronauts themselves. Discussing symbiotic microbes of animals (an otherwise very interesting section of this book!), Dunn states (page 179) that the hoatzin bird (a mostly vegetarian bird of South America that resembles the extinct archaeopteryx): “they ferment the leaves [of plants] in a special gut that they and they alone have evolved.” Nope. It’s actually an enlarged crop. All birds have them, but not necessarily so enlarged. Unless they’re phytovores (plant eaters); in such cases, as with phytovoric mammals, they have an enlarged chamber somewhere in the GI tract where microbes can break down the cellulose of the plant matter since animals do not possess the enzymes to do this. If you found plant-eating species of bird in Nature, you would expect it to have an enlarged crop just like the hoatzin. And although unknown to the author, there are examples including the owl parrot of New Zealand. Typically, parrots are omnivores, dining on all manner of fruits, nuts, and seeds, as well as insects and other small animals. But not the owl parrot. Since arriving on this island, some animal species have filled vacant herbivorous niches (including the “flightless” bats mentioned above; the only non-marine species of mammals native to New Zealand are bats). But to eat plant material, mammals and birds, like the owl parrot, had to evolve the GI tract to digest it. (Owl parrots consume all manner of plants and parts of plants, including young shoots, leaves, even stripping the bark from many trees much like the pesky deer in my backyard.)

A Natural History of the Future is a very important book for right now. Overall, my quibbles with the book are few. The author adeptly takes on a very broad topic, without overreaching, and this book should be required reading for our planet’s decision makers.

— Review by Britt Bunyard
— Originally published in Fungi