We are homo sapiens, the hominid species that has inhabited this planet for approximately 180,000 years. Like all other forms of life, we must find, secure, and consume food and water every day of our lives. For 95% of the time humans have been on Earth, hunting and gathering food was the primary technique of securing sustenance. Hunting and gathering called for a nomadic lifestyle that allowed humans to follow animal herds and take advantage of the seasonal life cycles of edible plants.  

Closer Look


Learn more about the historical emergence and development of agriculture in this article from Oregon State University.

Exceptions to this nomadic way of life were the more stationary groups of humans who had a fish-based diet. With a constant food source in one location, people could stay and develop their cultures in close proximity to the rivers, lakes, and oceans that contained their source of sustenance.

The beginning of agriculture was in the gradual transition of nomadic people who hunted animals and gathered plants into a more stationary people who planted, harvested, and tended plants and animals in one place. By making the cultivation of crops and domestication of animals the main source of human sustenance, humans distanced themselves from the wild food webs of their ancestors. Archaeologists believe that this stationary agricultural lifestyle arose independently in at least 11 regions around the globe.

Domestication of Plants and Animals

Map of Mesopotamia and Persia in the
Figure 12: The Fertile Crescent includes the rich soil found in the flood plain of the Nile, Euphrates and Tigris Rivers of Egypt, Mesopotamia and Persia.2

The earliest known domestication of plants occurred about 11,500 years ago in the Fertile Crescent, what is now Iran (Figure 12). Other locations of early plant and animal domestication were Northern and Southern China, New Guinea, India, Africa’s Sahel region, and several parts of the Americas.

Many early domestic plants included species still grown around the world today, such as wheat, barley, oats, rice, lentils, beans, squash and corn. In each case of plant domestication, humans took seeds from plants that were growing wild and planted them in concentrated areas. Over time, these early farmers observed the benefits of selecting seeds from the most productive individual plants for future planting. This process of artificial selection had many similarities to the process of natural selection explained in the Biodiversity Chapter.

As local human cultures grew into large civilizations and people began traveling long distances, seeds and roots of regional crops were traded, leading to the cultivation of non-native plants in parts of the world that had climate and soil types similar to the plant’s native land (Figure 13).

Map of the world showing crop origins.
Figure 13: Major crop species and the location of their regions of native origin. 3

The earliest evidence of animal domestication for agricultural purposes is that of sheep in western Asia around 10,500 years ago. This was followed by the domestication of goats and pigs in the same region. Cattle were domesticated in eastern Africa about 9,000 years ago and chickens were domesticated in Asia some 8,000 years ago. As humans spread out from place to place their domesticated animals went with them.

The development of agricultural societies involved successes and setbacks. The seemingly successful settled agricultural villages invariably experienced unintended setbacks such as new human diseases, new disease-related crop failures, new cycles of bounty and famine, and social tensions over the new agricultural division of labor. In fact, archaeological, anthropological and historical evidence shows that the average nutrition and health of humans living in early agricultural societies was lower than that of their hunter-gatherer predecessors.1 Despite this, the near-constant availability of food in agricultural societies gave rise to higher number and density of human population.

The Green Revolution

A trend toward increasing intensification and greater manipulation of food cultivation and animal domestication can be traced from these early agricultural communities to the present day. A notable spike in this development occurred in mid-twentieth century with the so-called ‘Green Revolution’. This revolution refers to the period from the 1940s to the late 1960s when the world saw a large increase in crop production, especially in developing countries. These increases were achieved using new high-yield crop varieties, new highly mechanized tools and machines, new irrigation techniques, and new technological advances in chemical pesticides, insecticides, and herbicides.

Norman Borlaug is identified as the key figure in bringing about the Green Revolution. Borlaug worked as a forester before getting a Ph.D. in plant genetics and pathology and played an influential role in promoting a methodology called the Borlaug Hypothesis. This hypothesis argues that if crop yields are increased on already-cultivated land, it will improve a growth in global food security without leading to an increase in global deforestation.

Borlaug’s work was central to the development of high-yielding and disease-resistant varieties of wheat, maize and rice. These high-yielding varieties were created using a scientifically-informed method of hybridizing crop strains where each parent strain had different desirable traits. The availability and utilization of these varieties was dependent on the development and intensification of chemical pesticide and fertilizer use; the increased mechanization of crop planting, harvesting, and processing; and an intensified irrigation infrastructure. The result was a remarkable increase in crop yield.

Closer Look


Read this archive from the New York Times from 1971 that discusses Dr. Borlaug’s defense for the use of pesticides as a method to increase food production.

Today, the increased availability of food worldwide through the industrial food system has helped the food supply keep better pace with population growth than in the past. However, from an environmental science perspective, there are some unintended negative consequences to this system.

Borlaug hoped that by improving crop yield, deforestation could be decreased. But the increased use of chemical fertilizers and pesticides and the increased scale of mechanization and irrigation mobilized alongside crop hybridization have increased global deforestation. Since the Green Revolution, more forests have been cut down, more swamps and wetlands have been drained, more animal habitats have been degraded, more plant and insect species have gone extinct, and more indigenous people and small, local farmers have been removed from their land than in any period of recorded human history.

Parallel Developments in Fishing Technology

The modern development of fishing techniques has been similar to that of agriculture’s Green Revolution. For most of its existence, fishing took place on a small scale within natural aquatic ecosystems. Fishing boats were dependent on human or wind power, and modest nets and lines were hauled in by hand.

Figure 14: Fish Trawling.4

By the 18th century, European fishing and whaling fleets had developed, beginning a fishing industry that would enter nearly all Earth’s oceans. Steam-powered fishing boats fueled by coal were introduced in the 1870s. These much larger and stronger boats dragged expansive nets over many miles of water, rather than setting them in a fixed location (Figure 14). Steam-power was eventually replaced by diesel and gasoline power, allowing boats to extend their fishing ranges and make more trips in a given period. With the improvements in marine navigation technology and sonar made during World War II, fishing boats could move into even more remote fishing grounds. Today, the largest fishing trawlers can run at over 10,000 horsepower and pull enormous ‘rock hoppers’ – fish nets rigged with heavy rubber wheels that crawl over the bottom of the ocean.

Industrial-scale fishing activity covers over 55% of the world’s oceans. A 2016 report by the United Nations Food and Agriculture Organization (FAO) estimates that nearly 90% of global fish populations are either fully fished or overfished.

Questions to Consider

  • Why do you think that some animals capable of being domesticated and others are not?
  • Norman Borlaug was motivated to develop hybridized seed strains in order to increase crop yield and thereby reduce the necessity for further deforestation of the planet. Hybridization has increased crop yield but has not prevented deforestation. Why do you think Borlaug’s goal of preventing deforestation has not been achieved?