Out of Africa

Two forms of life have come to develop eusociality, or, highly-sophisticated, complex societies: humankind and insects (ants, bees, wasps, and termites). The predominate attribute we ascribe to the surviving eusocial species must be luck: It was a long road that brought us here, with almost every conceivable obstacle to success standing in our path. The secondary attributes of eusocial species must include cooperation and division of labor. Yet it was Homo sapiens, alone among earth’s splendor, who broke from its forebears, bore itself out of our native habitats in Africa, charted course for the far ends of the globe and, along the way, developed thousands of years’ worth of rich, highly sentient, collaborative, if often brutal and violent, civilization. Our philosophy, science, and literature all ask the questions posed by Paul Gauguin in his masterwork: Where do we come from? What are we? Where are we going? These questions, woven eloquently into the context of evolutionary biology, form an endoskeleton for Edward O. Wilson’s new book on eusociality, The Social Conquest of Earth.

Wilson, who retired from teaching in 1996, but continues to hold the positions of Professor Emeritus and Honorary Curator in Entomology at Harvard, won his first Pulitzer for his 1978 landmark monograph, On Human Nature. In The Social Conquest of Earth, Wilson, whose expertise is in biodiversity and myrmecology (the study of ants), charts the unfolding of the human evolutionary biological paradigm, explaining how humankind, and separately, certain invertebrates like wasps, were predisposed to develop highly organized society by certain mutative or transitional events of natural selection, which themselves created new, unique paradigms—new, unforeseen possibilities for development and cognitive sophistication. Wilson writes:

The answer to the existential questions must lie in history, and that, of course, is the approach taken by the humanities. But conventional history by itself is truncated, in both its timeline and its perception of the human organism. History makes no sense without prehistory, and prehistory makes no sense without biology.

Pre-humankind split from the genetic line of chimpanzees some six million years ago. The pathways from there to here are nearly incalculable, and Wilson frequently employs the image of an evolutionary “maze.” That said, certain peak moments have emerged. Coincident with the “bipedal revolution,” in which certain pre-human primates amplified the trend towards bipedal walking that was already common among primates, our ancestors descended from trees and began to walk more fully upright, losing a great deal of their body hair in the process. Their sweat glands were dispersed more evenly through their limbs; arms developed the flexibility to accurately throw stones and spears; feet lengthened and pre-human began running one foot in front of the other. All of this, taken in aggregate, amounted to the evolving of the first humans into persistent long-distance hunters, who could run to ground their much speedier, though quicker to expire, prey.

This crucial development highlights an important characteristic shared by eusocial species: They create nests. Human campsites, which Wilson considers human nests, developed because humans had free hands capable of wielding tools and carrying food long distances. As Wilson points out, “There is an a priori reason for believing campsites were the crucial adaptation on the path to eusociality: campsites are in essence nests made by humans. All animal species that have achieved eusociality, without exception, at first built nests that they defended from enemies.”

Then, some two million years ago, pre-human beings began to eat meat, a development which forever changed their brain size and their dentition. One million years later, the safe transport and control of fire became our first advanced technology: it meant cooking came into existence. This was perhaps the sole development that catapulted us into modern manhood. Wilson demonstrates how the substance of human culture today ought to be seen as progressive variations upon the rudimentary social elements that made us human. In his chapter “Tribalism Is A Fundamental Human Trait,” the author asks what role is reflected, in terms of our development of eusociality, when we apply face paint and carry signs to a football match. Wilson asserts that the emblems of tribalism now reflected in sporting, or conversely, in tribal warfare, reflect certain social necessities crucial to the creation of populations, group survival, the hunting and harvesting of meat, cooking, and preparing food. Moreover, it implies the finer and less fine considerations of a human mind immersed in a group: altruism, empathy, mutual support. This view of mankind’s developmental trajectory brings the pursuits of evolutionary biology, archaeology, and cognitive psychology extremely close together. Social identity and personal identity work as a kind of echo chamber, one guise often amplifying or subduing the other. Solidarity, as Wilson had earlier demonstrated in his study, The Ants, in some cases began as an instinctual preponderance for self-sacrifice in order to protect females, such that:

Overall, big wars have been replaced around the world by small wars of the kind and magnitude more typical of hunter-gatherer and primitively agricultural societies. Civilized societies have tried to eliminate torture, execution, and the murder of civilians, but those fighting little wars do not comply.

By 40,000 B.C., Homo sapiens had broken out of Africa and had penetrated the European mainland, encountering and beginning their rapid defeat of Homo neanderthalensis.

Though the Neanderthals shared an ancient ancestor with Homo sapiens, they had evolved along nature’s changing course into an utterly distinct species. Within roughly 10,000 years of their contact with Homo sapiens, the Neanderthals as a species had fallen into the ever-amassing charnel house of history. This is important, Wilson asserts, because:

Although exalted in many ways, we remain an animal species of the global fauna. Our lives are restrained by the two laws of biology: all of life’s entities and processes are obedient to the laws of physics and chemistry; and all of life’s entities and processes have arisen through evolution by natural selection.

Indeed, we are creatures of our biosphere. New methods of genome sequencing and analysis, Wilson insists, indicate that evolution, specifically, microevolution, is an ongoing occurrence in human beings. We are still evolving, much as humans have always evolved. As we persevered our way out of Africa and extended our range over the entire planet, we developed various attributes to reflect residence at high altitudes, or in places of extreme temperature and cold. Our physiology and digestive systems morphed when we began cooking food.

We have among our accolades the works of Shakespeare, the Great Wall of China, the Magna Carta and a Moon landing. What portion of us will we take along as we evolve—what part of us will be left behind? How will our geography influence genetic mutation and genetic drift? Importantly, how should our new and growing consciousness of our origins and our methodological understanding of the pathways which brought us to the present moment, affect our conceptions of ethics, sexuality, warfare, conservation, and ecology? Put another way, as we develop a sense for where we came from, and get a small glimpse of what we really are, we must try to answer where we are going.

Wilson hazards a guess:

For the immediate future…emigration and ethnic intermarriage have taken over as the overwhelmingly dominant forces of microevolution…an unprecedented dramatic increase in the genetic variation within local populations…this change, unique in human evolutionary history, offers a prospect of an immense increase in different kinds of people worldwide, and thereby newly created physical beauty and artistic and intellectual genius.

In answering the question, “Where are we going?,” Wilson, acknowledging an inherent human myopia, suggests we ask ourselves the variant, “Where not to go?” Wilson warns on moral grounds against eugenic or volitional selection, that is to say, the genetic modification of infants, insisting we should cherish the totality of genetic diversity on the planet, not merely celebrate the differences between humans. Here, as in greater systems of eusociality, it is the total richness that counts.

Part of Wilson’s breakthrough in The Social Conquest of Earth includes his willingness to look at divergent or seemingly unrelated forms of eusocial life in his attempt to understand human evolution. It might be a suitable mantra for the years ahead, one that reflects both a social acceptance of diversity, and which responds to the ecological needs and predispositions of earth; it is a sentiment that mirrors the scope of Wilson’s own life work, exemplified in this important volume: it is the total richness that counts.