When searching databases and the open Internet, use and combine these Key Terms:

• Anthropocene epoch — A new epoch, not formally accepted by geologists, during which our species has become the dominant force for change in the biosphere. The Anthropocene marks the end of the Holocene epoch, about the time of the Industrial Revolution, 200 years ago.
• Black Death — The fourteenth-century outbreak of bubonic plague, which killed up to half the population of Europe.
• carrying capacity — The maximum number of individuals that a region’s resources can support or sustain.
• exchange networks — Networks that link people, societies, and regions through the transfer of information, goods, people, and sometimes disease. All forms of collective learning work through exchange networks.
• globalization — The expansion of exchange networks until they begin to reach across the entire world.
• Holocene epoch — The geological epoch that begins with the end of the last ice age, about 13,000 years ago, and ends at the start of the Anthropocene epoch, about 200 years ago.
• hub region — A geographical region characterized by an exceptional amount of exchange of people, ideas, and goods taking place—Mesopotamia, for example. After 1500, the Atlantic regions became a significant hub region through Europe’s control of the major international sea routes.
• Industrial Revolution — A period of technological innovation starting in England late in the eighteenth century that resulted in a major change in the way goods were produced, and caused a major shift in global economics. These innovations came as a result of the systematic use of fossil fuels in place of human and animal power to manufacturing, communications, and transportation.
• Malthusian cycles — Long cycles of economic, demographic, cultural, and political expansion, generally followed by periods of crisis and decline. These cycles, generally lasting several centuries, are apparent throughout the era of agrarian civilizations, and were probably set into motion by the inability of innovation to keep pace with population growth. Named for Thomas Malthus (1766–1834), an English pastor and economist.
• Modern Revolution — A deliberately vague label for the revolutionary transformations that have created the modern world. The Modern Revolution began around 1500 and ushered in the Modern era of human history.
• Silk Roads — The trade routes connecting Europe to the Middle East, India, and China.
• steam engines — Machines that burn coal to produce steam, used to perform mechanical work. James Watt configured the first profitable one at the time of the American Revolution. Their use launched human society over a threshold no longer limited by the annual flow of solar energy.
• steppe lands — Arid grasslands that are suitable for grazing animals but too dry for agriculture.
• world zones — Four unconnected geographic zones that emerged as sea levels rose at the end of the last ice age. The four world zones are: Afro-Eurasia (Africa and the Eurasian landmasses, plus offshore islands like Britain and Japan); The Americas (North, Central, and South America, plus offshore islands); Australasia (Australia, the island of Papua New Guinea, plus neighboring islands); and the island societies of the Pacific (New Zealand, Micronesia, Melanesia, and Hawaii).