Rob Dunn

Ideas

01.06.2022 07:00 AM

Humans—convinced of our own power and control—tend to ignore the laws of nature. But that is a mistake.

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Photo-Illustration: Sam Whitney; Getty Images

Everyone wants to know what’s to come—right? But our obsession with predictions reveals more about ourselves.

This story is adapted from A Natural History of the Future: What the Laws of Biology Tell Us About the Destiny of the Human Species, by Rob Dunn.

When we humans imagine the future, it is common to picture ourselves nested within an ecosystem populated by robots, devices, and virtual realities. The future is shining and technological. The future is digital, ones and zeros, electricity and invisible connections. The dangers of the future—automation and artificial intelligence—are of our own invention. Nature is an afterthought in our contemplation of what comes next, a transgenic potted plant behind a window that does not open. Most depictions of the future do not even include nonhuman life, except on distant farms (tended by robots) or in indoor gardens. We put up a levee between our civilizations and the rest of life, and that’s a mistake—both because it is not possible to hold life at bay and because in trying to achieve such a scenario, we do so at our own expense. Not only does this defy our place in nature, but also what we know about the rules of nature.

In school, we learn about some of these laws—gravity, inertia, and entropy, to name a few. But there are also laws of the motions of cells, bodies, ecosystems, and even minds. These are the biological laws that we need to have in the front of our mind if we are to make any sense of the years ahead.

Some of the laws of biological nature are laws of ecology. The most useful of these are universal. These biological laws of nature, like the laws of physics, allow us to make predictions. However, as physicists have pointed out, they are more limited than the laws of physics because they only apply to the tiny corner of the universe in which life is known to exist. Still, given that any story that involves us also involves life, they are universal relative to any world we might experience. Knowing about these laws helps us understand the future into which we are—arms flailing, coal burning, and full speed ahead—hurling ourselves.

Most of the laws of nature are well known to ecologists. Though many were first studied more than a hundred years ago, they have been elaborated and refined in recent decades with advances in statistics, modeling, experiments, and genetics. These laws predict which species are likely to move around the Earth in response to climate change, how species will evolve in response to our ever-growing cities, the sorts of behaviors that will allow species to thrive in an ever more variable world, and much more. They govern the response of life to each of our individual or collective actions. Because these laws are known and even intuitive to ecologists, they often don’t mention them: “Of course that is true. Everyone knows. Why talk about it even?” But these laws are often not intuitive if you haven’t spent recent decades thinking and talking about them. Those that are aware of them ignore them out of the belief in humanity’s own power, the hubris of thinking we are fully in control. As a result, their consequences have a tendency to surprise ecologists and non-ecologists alike, to catch us with our collective guard down and punish us, whether with global pandemics, resistant weeds, or persistent changes in the ecosystems on which we depend.

Charles Darwin’s elegant revelation of the way life evolves, natural selection, is one such law. Darwin imagined this to be a slow process, but we now know that it can happen very quickly. Evolution by natural selection has been observed in real time in many species, which is not surprising. What is surprising is the river-like inevitability with which the consequences of this simple law flow into our daily lives each time we, for example, try to kill a species.

We do this in our homes, hospitals, backyards, farm fields, and even, in some cases, forests when we use antibiotics, pesticides, herbicides, and any other “-cide.” And the effects are always predictable.

Recently, Michael Baym and colleagues at Harvard University constructed a giant Petri plate, or a “megaplate,” divided into a series of columns. Then, Baym added agar, which is both food and habitat for microbes. The outside column on each side of the megaplate contained agar and nothing more. Moving inward, each subsequent column was laced with antibiotics at ever-higher concentrations. Baym then released bacteria at both ends of the megaplate to test whether they would evolve resistance to the antibiotics.

The bacteria had no genes that conferred resistance to the antibiotics; they entered the megaplate as defenseless as sheep. And if the agar was the pasture for these bacterial “sheep,” the antibiotics were the wolves. The experiment mimicked the way we use antibiotics to control disease-causing bacteria in our bodies. It mimicked the way we use herbicides to control weeds in our lawn. It mimicked each of the ways we try to hold back nature each time it flows into our lives.

The law of natural selection would predict that so long as genetic variation could emerge, via mutation, the bacteria should eventually be able to evolve resistance to the antibiotics. But it might take years or longer. It might take so long that the bacteria would run out of food before they evolved the ability to spread into the columns with antibiotics, the columns filled with wolves.

It didn’t take years. It took 10 or 12 days.

Baym repeated the experiment again and again. It played out the same each time. The bacteria filled the first column and then briefly slowed, before one and then many lineages evolved resistance to the next highest concentration of antibiotics. This continued until a few of the lineages evolved resistance to the highest concentration of antibiotics and poured into the final column, like water over a levee.

Seen sped up, Baym’s experiment is horrifying. It is also beautiful. Its horror lies in the speed with which bacteria can go from being defenseless to indestructible relative to our power. Its beauty lies in the predictability of the experimental results, given an understanding of the law of natural selection. This predictability allows two things: It allows us to know when resistance might be expected to evolve, whether among bacteria, bedbugs, or some other group of organisms; it also allows us to manage the river of life so as to make the evolution of resistance less likely. An understanding of the law of natural selection is key to human health and well-being and, frankly, to the survival of our species.

There are other biological laws of nature with similar consequences. The species-area law governs how many species live on a particular island or habitat as a function of its size. This law allows us to predict where and when species will go extinct, but also where and when they will evolve anew. The law of corridors governs which species will move in the future as climate changes, and how. The law of escape describes the ways in which species thrive when they escape their pests and parasites. Escape accounts for some of the successes of humans relative to other species and for how we have been able to achieve such extraordinary abundance relative to other species. The law frames some of the challenges that we will face in the coming years when our possibilities of escape (from pests, parasites, and the like) are fewer. The law of the niche governs where species, including humans, can live and where we are likely to be able to successfully live in the future as climate changes.

These biological laws are alike in that their consequences play out independently of whether or not we pay them heed. And, in many cases, our failure to pay them heed ushers us into trouble. Failing to pay attention to the law of corridors leads us to inadvertently help problem species (rather than beneficial or simply benign species) into the future. Failure to pay attention to the species-area law leads to the evolution of problem species such as a new species of mosquito in the London Underground railway system. Failure to pay attention to the law of escape leads us to squander moments and contexts in which our bodies and crops are free of parasites and pests. But the laws are also similar in that if we pay them heed, if we consider how they will influence the natural history of the future, we can create a world that is more forgiving of our own existence.

Then there are laws that relate to the ways in which we, as humans, behave. As laws of human behavior they are both narrower and messier than the broader laws of biology; they are as much tendencies as laws. Yet they are tendencies repeated across times and cultures, tendencies that are relevant to understanding the future both because they suggest how we are most likely to behave and because they also indicate what we need to be aware of if we are to go against the rule.

One of the laws of human behavior relates to control, to our tendency to try to simplify life’s complexities, just as one might try to straighten and channel an ancient and powerful river. The coming years will present more novel ecological conditions than have occurred in millions of years gone by. Our human population will swell. More than half the Earth is now covered by ecosystems we have created—cities, farm fields, waste-treatment plants. We now, meanwhile, control, directly and incompetently, many of the most important ecological processes on Earth. Humans eat half of all the net primary productivity, the green life that grows, on Earth. And then there is the climate. In the next 20 years, climatic conditions will emerge unlike any humans have ever been exposed to before. Even under the most optimistic scenarios, by the year 2080 hundreds of millions of species will need to migrate to new regions and even new continents in order to survive. We are reshaping nature at unprecedented scales, and for the most part, we are absentmindedly looking the other way while doing so.

As we reshape nature, our behavioral tendency is to use more and more control—to make our farm fields simpler and more industrial and to make our biocides ever stronger. This is a problematic approach in general, but it is especially so in a changing world, where our behavioral tendency to try to control is at odds with two laws of diversity.

The first law of diversity is manifest in the brains of birds and mammals. In recent years, ecologists have revealed that animals with brains capable of using inventive intelligence to carry out novel tasks are favored by variable environments. These animals include crows, ravens, parrots, and some primates. Such animals use their intelligence to buffer the diverse conditions they encounter, a phenomenon described as the law of cognitive buffering. When environments that were once consistent and stable become variable, these species with inventive intelligence become more common. The world becomes a crow’s world.

A second law of diversity, the diversity-stability law, states that ecosystems that include more species are more stable through time. An understanding of this law and of the value of diversity proves useful in the context of agriculture. Regions with a greater diversity of crops have the potential to have more stable crop yield from year to year and hence less risk of crop shortages. Repeatedly, although our tendency is often to try to simplify nature when we are confronted with change, or even to rebuild it from scratch, maintaining nature’s diversity is more likely to lead to sustained success.

When we try to control nature, we often come to imagine ourselves as outside nature. We speak of ourselves as if we were no longer animals, as if we were a species alone, disconnected from the rest of life and subject to different rules. This is a mistake. We are both part of and intimately dependent on nature. The law of dependence states that all species depend on other species. And we, as humans, are probably dependent on more species than any other species ever to exist. Meanwhile, just because we depend on other species does not mean nature depends on us. Long after we go extinct, the rules of life will continue. Indeed, the worst assaults we carry out on the world around us nonetheless favor some species. What is remarkable about the big story of life is the extent to which it is ultimately independent of us.

Finally, one of the most consequential sets of laws regulating how we plan for the future relates simultaneously to our ignorance about nature and our misperceptions about its dimensions. The law of anthropocentrism states that, as humans, we tend to imagine the biological world to be filled with species like us, species with eyes, brains, and backbones. This law emerges from the limits of our perception and the limits of our imaginations. It is possible that we might someday escape this law and break through our ancient biases, but this is unlikely.

Repeatedly scientists have announced the end (or near end) of science, the discovery of new species, or the discovery of life’s extremes. Usually, in doing so, they position themselves as having been key to putting the final pieces in place. “Finally, now that I am done, we are done. Look what I know!” And repeatedly, after such announcements, new discoveries have revealed life to be far grander and more poorly studied than had been imagined. What I call “Erwin’s law” reflects the reality that most of life is not yet named, much less studied. This law is named for a beetle biologist, Terry Erwin, who, with a single study in a rainforest in Panama, changed our understanding of the dimensions of life. Erwin initiated a revolution in our understanding of life analogous to the Copernican Revolution. Just as that revolution was complete when scientists came to agree that Earth and the other planets circled the sun, the Erwinian revolution will be complete when we remember that the living world is far vaster and more unexplored than we imagine it to be.

Erwin’s law reminds us that despite our ability to tinker godlike with the workings of Earth’s living systems, we remain more ignorant than we are knowing. And yet, even amidst the extraordinary breadth and depth of our ignorance (perhaps seven out of eight animal species is yet to be named, much less studied, and billions of bacteria await discovery, some of them living on your body right now as you read), we have to make decisions about our relationship with the rest of life. We make them each time we eat, each time we drive, and each time we treat an illness. Our best hope, in this world in which we know so little and affect so much, is to take into account the laws and lawlike rules of life in our planning.

Only by keeping nature’s laws in mind can we imagine a sustainable future for our species, a future in which our cities and towns are not repeatedly flooded by the consequences of our failed attempts to manage life—not only by water but also by pests, parasites, and hunger. We will fail again and again if we ignore these laws.

The bad news is that our default approach to nature seems to be to try to hold it back. We tend to fight nature at our own expense and then blame vengeful gods when things don’t work out. The good news is that it doesn’t have to be that way: If we pay attention to a set of relatively simple laws of life, we have a much better chance at surviving a hundred years, a thousand years, or even a million years. And if we don’t, well, ecologists and evolutionary biologists together actually have a pretty good idea of the trajectory of life in our absence.

This is a modified excerpt from A Natural History of the Future: What the Laws of Biology Tell Us about the Destiny of the Human Species by Rob Dunn. Copyright © 2021. Available from Basic Books, an imprint of Hachette Book Group, Inc.

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