Most scholars accept the “Out of Africa” thesis, which asserts that forerunners to modern humans emerged in Africa approximately 200,000 years ago and began migrating out of Africa 100,000 years ago. These homo sapiens sapiens dispersed across the globe, adapting to diverse environmental conditions and, more recently, domesticating plants and animals. Only with the emergence of settled agriculture around 15,000 years ago did significant cultural differences appear among humans.
Precursors to Modern Humans
The discoveries within the past century regarding the origins of human existence have challenged the creationist accounts of human origins found in cultural traditions across the globe.
CREATION MYTHS AND BELIEFS
Scientific knowledge has dated the origin of the universe back some 15 billion years. It places the early development of hominids at around 6 or 7 million years in Africa. This information has caused consternation for religious creation beliefs, which in many cultures date back thousands—not millions—of years. Even those cultures with million-year cycles have trouble reconciling that the ancestor s of humankind evolved from apes.
EVOLUTIONARY FINDINGS AND RESEARCH METHODS
As hominids began to evolve over several million years, no single variability separated them from other creatures. Rather, a combination of traits began to differentiate hominids from other animals. These traits, which included bipedalism, control of fire, toolmaking, language, and self-consciousness, were in place about 150,000 years ago.
EARLY HOMINIDS AND ADAPTATION
The first hominids were smaller than most people today and struggled for survival—they were the hunted, not the hunters. Early australopithecines—precursors to modern humans—developed into six species. Perhaps their strongest trait was their ability to adapt.
Lucy A relatively complete skeleton, with humanlike teeth and jaw, and half a million years older than any other known hominid skeleton at the time, was discovered in Ethiopia in 1974. Her skeleton gave evidence that human ancestors were walking around 3 million years ago.
Adaptation No straight-line descent from early hominids to modern humans exists, due to the dictum of adapt or perish. Some hominid groups proved better at dealing with changing environments and climates better than others. But the trait that hominids adapted that set them apart from other hunters was bipedalism. Walking on two feet gave them the ability to use their hands and arms for other purposes. In addition, bipedalism gave hominids the ability to walk long distances—to migrate.
Environmental Changes The slow end to the last Ice Age brought about a cooling and drying phase in the Rift Valley, causing forests to shrink and savannas to spread. It was here that early precursors to humans developed. Cognition developed along with bipedalism and became the basis for further adaptations, such as toolmaking, while memory and observation helped hominids hunt and gather. It also helped them avoid predators. Early hominids lived in bands of about twenty-five, making them highly social. Occasionally hominid groups would band together into larger communities of up to 500 individuals. Social relations encouraged the development of means of communication through gestures and perhaps an early form of language.
Diversity Different kinds of hominids lived in roughly the same environment between 3 and 4 million years ago, indicating greater diversity than previously thought. Orrorin hominids, from what is today Kenya, appear to have been walking on two feet—at least part of the time—7 million years ago. Other bipeds have been discovered in modern-day Ethiopia that date back at least 5 million years.
THE FIRST HUMANS: HOMO HABILIS
During the Ice Age, as radical changes in climate occurred, the first “true humans” (called homo) appeared. They had large brains and could deliberately fashion tools to exploit resources in their environment. Louis and Mary Leakey discovered an almost intact skull of this Homo habilis (or “Skillful Man”), which they named “Dear Boy.”
EARLY HUMANS ON THE MOVE: MIGRATIONS OF THE HOMO ERECTUS
By 1 million BCE, only one species of hominid still survived: Homo erectus, or “Standing Man.” Homo erectus needed extended periods of care for their young so that their larger brains could develop. The years of maturation also allowed adults to train offspring in hunting and gathering. In addition to being fully bipedal, Homo erectus made rudimentary efforts to control their environments. The use of fire both provided heat in colder climes and expanded diets. Homo erectus spread out of Africa about 1 to 2 million years ago and moved rapidly across the globe, yet Homo erectus and Homo habilis are unlikely to have been direct ancestors of modern humans.
The First Modern Humans
Homo sapiens moved out of Africa and became the sole “human” species sometime between 120,000 and 50,000 years ago. They brought with them one of the final and most important traits in human evolution—complex language.
HOMO SAPIENS AND THEIR MIGRATION
As a period of warm, dry climate materialized about 200,000 years ago, a bigger-brained and more adaptable variant of human species, the Homo sapiens, emerged in the highlands of eastern Africa. Homo sapiens followed the trails blazed by other hominids out of Africa and developed distinct cultures as well as aesthetic tastes and religious beliefs in different settings. Homo sapiens migrated even further than previous hominids, crossing into North America.
CRO-MAGNON HOMO SAPIENS REPLACE NEANDERTHALS
Neanderthals were members of a migration of hominids out of Africa that preceded the Homo sapiens. With brains that lacked the complex structure of modern humans, the Neanderthals had limited cognitive abilities. Scholars in the first half of the twentieth century who rejected the “Out-of-Africa” thesis pointed to the Neanderthals as forerunners of modern Europeans who had developed into a distinct race through long-separation from other hominids. Today, however, most scholars reject this view. Instead, the Neanderthal’s clumsy build and limited language proficiency left them unable to compete with the Cro-Magnon Homo sapiens who arrived in the region. By 30,000 BCE all the genetic cousins to the Homo sapiens, including the Neanderthals, were extinct.
EARLY HOMO SAPIENS AS HUNTERS AND GATHERERS
Homo sapiens subsisted as hunters and gatherers in small and highly egalitarian bands in which women made a large contribution to a band’s survival and held a high status.
Art and Language
The first Homo sapiens developed cultural forms that reflected their self-consciousness and their quest to forge a relationship with their environment.
The ability to draw gave Homo sapiens adaptive strategies such as understanding their environment and establishing mythologies that aided them in surviving challenging circumstances. Over a period of 30,000 years Homo sapiens drew images of large game that were powerful symbols of maleness and femaleness. Few images of humans were drawn, although sculptures did include human female figures along with animals. Only Homo sapiens developed this cognitive capacity for symbolic expression through which they learned to make sense of themselves, nature, and the relationship between humans and their environment.
Language, whereby words are arranged in particular sequences to convey meaning, requires a large brain and complex cognitive organization. Language, thus, starkly sets off humans from other animals. Humans are able to produce and process distinctive sounds more quickly than other primates. Complex language arose about 50,000 years ago and accelerated the rate of change and ability to adapt by humans. With language humans could accumulate bodies of knowledge and transmit them across time. As humans spread across the globe, nineteen separate language families emerged.
The Beginnings of Food Production
In at least five separate locations over a 5,000-year period, humans learned to cultivate wild grasses and cereals and domesticate wild animals. This agricultural revolution led to a vast population expansion.
EARLY DOMESTICATION OF PLANTS AND ANIMALS
Gradually knowledge about the domestication of plants and animals was accumulated. Ideal environmental conditions in Southwest Asia around 9000 BCE allowed humans to experiment with new ways of organizing themselves, and permanent settlements appeared. Settled communities allowed humans to take risks, spurring agricultural innovations.
Domestication of Animals At the same time, animal domestication emerged as animals became dependent on humans for feed. Controlling animal reproduction soon was recognized as more reliable than hunting to obtain protein, and “pastoralism” emerged.
PASTORALISTS AND AGRICULTURALISTS
Pastoralism emerged around 5500 BCE, at roughly the same time as full-time farming. Initially herders lived around agricultural settlements and moved herds only small distances. Eventually a divide arose and nomadic pastoralism developed. Communities moved long distances on horseback, moving to new grazing lands when the number of animals in a region outstripped the food supply. The development of nomadic pastoralism on the steppes of northern Afro-Eurasia is thought to have occurred by 3000 BCE. The emergence of the division between agriculturalists and pastoralists became one of the great divides in Afro-Eurasian history.
Emergence of Agriculture in Other Areas
SOUTHWEST ASIA: THE REVOLUTION BEGINS
The first agricultural revolution occurred in a region of Southwest Asia known as the Fertile Crescent and was characterized by the presence of rich soils and regular rainfall. By 9000 BCE humans were selecting and storing seeds and sowing those seeds in seedbeds. The Tigris and Euphrates river valley only adopted these practices several millennium later as primitive irrigation methods were developed. Between 9000 and 4000 BCE similar agricultural revolutions occurred in several other regions across the globe where climate change, accumulating knowledge of plants and animals, and growing populations encouraged agricultural innovations.
EAST ASIA: RICE AND WATER
The Yellow and Yangzi rivers in China carried alluvial loess topsoil to the northern China coastline, where it was deposited in a region that had ample fresh water and heavy rains. Rice in the south and millet in the north became staple crops in the seventh and sixth millennia BCE as ox plows and water buffalo plowshares were utilized in preparing the soil. In addition, both China and Japan developed pottery, which enabled cultivators to store crops.
EUROPE: BORROWING ALONG TWO PATHWAYS
Domestication of plants and animals in Europe was achieved by the migration of individuals in the Mediterranean region and by the transmission of ideas toward the north and west. In the north, domestication occurred slowly because new crops and animals appropriate for the colder climes had to be discovered. Agricultural settlements remained small in size, but overall population rose significantly.
THE AMERICAS: A SLOWER TRANSITION TO AGRICULTURE
Crossing Beringia meant adapting to new flora and fauna as populations moved southward. After the glacier melt in 12,500 BCE, the Americas became a separate world. Early humans in the Americas, known as the Clovis people, were hunter-gathers.
Climatic Change and Adaptation Communities adapted to climatic shifts that killed off their major source of food, the large prehistoric mammals. In the Americas, the cluster of innovations that revolutionized food production in the Fertile Crescent did not appear. Thus, most communities adopted settled agriculture without abandoning basic survival strategies of hunting and gathering. Some developed pottery, others irrigation systems, and eventually, trade networks developed.
Domestication of Plants and Animals Maize offered real advantages to Mesoamerican diets, but its domestication was a slow process. Animals were not domesticated as a source of protein or for long-distance haulage. Human communities were isolated from each other and, thus, more narrowly adapted to local ecozones.
AFRICA: THE RACE WITH THE SAHARA
Settled agriculture developed in the Sahel region just south of the Sahara Desert. If settled agriculture includes the systematic collection of aquatic life, then the agricultural revolution in the Sahel may predate the similar revolution in the Fertile Crescent of Southwest Asia. Warming conditions around 4,000 years ago led men and women in this region to wander into new regions, adopting local crops in their new environments and spreading knowledge of plant and animal domestication.
Revolutions in Social Organization
As settled communities grew in size, specialized craftworkers emerged who produced pots, textiles, or tools that they could trade with cultivators and pastoralists. Craft specialization and production surpluses contributed to early social stratification.
SETTLEMENT IN VILLAGES
The first settled communities emerged as clanlike societies based on kinship networks that built simple, circular structures. Populations grew and task specialization expanded as the use of natural resources intensified. People began to create buildings in rectangular design—a shape not found in nature. Such buildings allowed interior walls, creating more private spaces within structures. As people established their own, human-created spaces in which to gather and worship the forces of nature, such structures also became spaces on which to display art and imagery. After 5500 BCE, small villages began to appear in the Tigris and Euphrates river valley, and their inhabitants worked together to build irrigation systems to water the fields. These communities became socially stratified as status could be established by birth rather than through the merits of one’s work.
MEN, WOMEN, AND EVOLVING GENDER RELATIONS
For the early hominids, the differences between males and females were primarily biological, based upon the fact that females gave birth to offspring. Only with the appearance of Homo sapiens did “gendered” (socially and culturally based) relations between males and females emerge. Such gendered relations required imaginative and complex symbolic forms of thought and expression. Gender roles became more pronounced as the food-producing revolution emerged. As men took control over plowing, women were left to the backbreaking and repetitive tasks of planting, weeding, and harvesting— the growing drudgery of work. Senior males also became dominant in households and in communities as political and cultural hierarchies emerged that placed men in authority over women.