The Dominant Animal

Human Evolution and the Environment

Protected: Excerpt

From the Prologue of The Dominant Animal

Human beings live in a world of change and always have. But in recent decades, the world has been changing faster than ever before, largely because of human modifications of our planet, and the pace is accelerating. Those modifications have, at least temporarily, enabled the power and consumption patterns of a billion or so people to be enormously enhanced and allowed a couple of billion to be doing all right, while leaving a few billion others living in poverty and, often, hopelessness.

The acceleration of change traces to the rapid expansion in the human population since World War II, and to an explosive flowering of science and technology that has greatly increased the ability of our species to manipulate resources and the natural world. The remarkable technological accomplishments of modern human beings have had unfortunate, if unintended, consequences. They have not been matched by comparable advances in how wisely we treat one another and our environment. As a result, the weight of great human numbers coupled with our unprecedented technological capacity now threatens to overwhelm Earth’s ability to sustain what has become a global civilization. Those unintended consequences—civilization’s threats to its own ability to persist—are often called the “human predicament.”

How one species, Homo sapiens, has become so powerful that it can significantly undermine the ability of Earth’s environment to support much of life—including our own—is a central theme of this book. Humanity’s rise to dominance is a result of both genetic and cultural evolution, both of which led to scientific advances that have spawned ever more powerful technologies. Both kinds of evolution have occurred largely in response to changing environments, and both, in turn, have been responsible for dramatic environmental alterations. Knowledge of these reciprocal evolution-environment interactions is critical to our ability to make wise decisions affecting the long-term success of our species and of the natural world upon which it is utterly dependent.

Besides providing the means to transform most of Earth’s land surface, disrupt the life of its oceans, and significantly alter its atmosphere, science and technology have greatly enhanced our understanding of how the world works. Armed with computers, satellites, chemistry labs, electron microscopes, binoculars, butterfly nets, and theories, scientists have gained a reasonably comprehensive understanding of how Earth and its myriad inhabitants—including ourselves—interact and how they have changed over time. Having anything close to this level of knowledge is something new in the more than 100,000-year history of our species. In theory, we could use that knowledge to create a sustainable civilization—one in which human beings live happy, productive lives into the indefinite future. Whether we can manage that in practice remains to be seen.

Relatively recently, people’s understanding of the world was quite different. An educated Englishman in the seventeenth century believed the Creation, including humanity, to be organized into a great “chain of being” that stretched “from the foot of God’s throne to the meanest of inanimate objects.” Everything, living or not, was assigned its place in an unchanging order: angels ranked between God and kings, kings above commoners, people above other animals, lions over mice, mice above plants, plants above rocks, and so on. It was a chain, not a ladder; one couldn’t climb or descend it. The basic characteristics of human beings weren’t thought to change, nor usually did their status in society; butterflies didn’t change, mountains didn’t change, the air people breathed didn’t change, and poor girls didn’t marry royalty. Indeed, nothing fundamental was thought to have been altered since the world was created, on October 23, 4004 bc, as Archbishop of Armagh James Ussher calculated in 1650. In modern terms, seventeenth-century savants were ignorant about the most basic aspects of the world.

But by Archbishop Ussher’s time, ironically, change was already in the wind. Despite having been (in theory) put on the throne by God, Charles I of England was executed for “treason” on January 30, 1649, by human beings. This act of regicide defied a millennium of custom and sermons and indicated a weakening of belief in the great chain. In fact, it heralded a fundamental shift. Previously, most scholars had focused on received wisdom from texts. In the West, these included the Bible as well as the classical works of scholars, especially Aristotle, who wrote extensively on physics, philosophy, natural history, logic, and psychology three and a half centuries before Christ; and Thomas Aquinas, with the five proofs of the existence of God he developed in the late thirteenth century. Both Aristotle and Aquinas themselves had an empiricist bent, meaning they tried to make sense of the natural world through observation and experience (though not experiment), as most scientists do today. But in the Middle Ages most people were not trying to acquire new knowledge from nature; they had been taught to believe what their putative superiors said and to do as they were instructed.

After Ussher’s time, the focus on received wisdom was gradually replaced in the West by a new spirit of independent inquiry and discovery. Galileo (1564–1642), rolling marbles down inclined planes and making careful measurements to investigate gravity, began to undermine the vague Aristotelian notion that each object sought its “natural place.” Science was being born. A “question-and-test” school of intellectual discourse was weakening the old “believe-and-obey” school. In the Age of Enlightenment that followed, spurred by scientific advances and growing discontent with oppressive monarchies, ideas of change and progress were appearing everywhere in Europe, along with belief in the power of reason to explain the universe and to improve people’s lot. In part, ascendance of that view was due to the work of the extraordinary mathematician and physicist Isaac Newton (1643–1727), who, among many other things, showed how the mathematical laws that described the motion of objects on Earth also governed the movements of celestial bodies. Newton was followed a century and a half later by that greatest of biologists Charles Darwin (1809–82), who explained how the vast diversity of living creatures was generated. His ideas gave the coup de grâce to the prevalent static view of the world—he “Newtonized” biology by showing that myriad seemingly disparate facts could be explained by a set of unifying rules of change.

Increased understanding of physical science laid the groundwork for the industrial revolution, which later mass-produced wonders ranging from pistols with replaceable parts to automobiles, jet aircraft, digital computers, and nuclear missiles. At the same time, the discoveries of biological science started to end plagues and improve health, and thus lower death rates, and, by so doing, encouraged unprecedented human population growth. Those biological discoveries also began to explain where human beings had come from, how we fit into nature, and how we got smart enough to create and apply science, become the dominant animal on the planet, and even contemplate our possible destinies.

By substantially increasing the power of human beings to modify their environments, the industrial revolution and the population explosion laid the groundwork for a nineteenth- and twentieth-century human conquest of nature on a scale hitherto undreamed of. Societies around the globe cleared vast areas of forest to raise crops and build cities, lacing the world with railroads and then highways, filling the skies with jet aircraft, and creating a vast array of plastics and other chemical products never seen in nature. If at first this seemed a triumphal march, by the middle of the twentieth century a growing minority of scientists and others had begun to realize that the “conquest” also amounted to a vast assault on the global environment that had increasingly serious implications for the future of humanity.

Questions of where people came from—that is, how we gradually changed from tiny, mouselike creatures 60 million years ago into the planet’s dominant animal—and of how we have both altered and been influenced by our physical and biological environments are inextricably intertwined. This book deals with what scientists have discovered about the origins of people, what is known of our diverse cultures, and how our environments shaped those origins and cultures and now shape the human future. And it explains the equally important obverse of the coin: how we are reshaping our global environment, helping to steer our species’ trajectory. It is a story about scientific discovery in the human realm. It describes both what scientists have found out about us, our surroundings, and the dramatic consequences of our activities, and how science, the human activity that gave us the power to dominate Earth, can help us better understand the predicament we have created for ourselves and thereby avoid its worst consequences.

The Dominant Animal is thus intended to be a concise account of human beings’ interactions with one another and with the biophysical world in which we evolved, and how we came to dominate land and water, atmosphere, microbes (maybe!), plants, and animals. To understand the roles we play in our social and biophysical environments, we need to look at what science can tell us about topics as seemingly disparate as climate change, genes, sex, religion, epidemics, ethics, education, politics, and nuclear war. This volume attempts to explain what human dominance means for the functioning of our planet and therefore for our future. Amazing as it may seem in an era of increased environmental awareness, this story is rarely told in its entirety.

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