AP Human Geography Unit 2: Population and Migration Patterns and Processes Notes

August 1, 2021

With tons of information to retain as you study for the AP Human Geography Exam, use our concise unit summaries and key terms to help you organize your AP Human Geography Exam studies. Keep reading for our summary and key terms for AP Human Geography Unit 2.

AP Human Geography Unit 2 Summary

During the past two centuries, the world’s human-population growth has exploded. The causes, mechanisms, and consequences of this tremendous increase are multifaceted. Population geographers collect demographic data and use mathematical equations to understand trends in population growth and to make predictions about the future. Population growth and population density both vary dramatically over space—some countries are not growing at all, while others are doubling their populations every couple of decades. The fastest-growing countries are also among the poorest, and in many cases rapid population growth has led to severe environmental degradation and human suffering. However, environmental problems are not simply a function of population growth; they also result from the overconsumption of resources. Conse­quently, issues regarding population, consumption, social justice, and environmental sustainability provide geographers with many fascinating and complex ­questions.

AP Human Geography Unit 2 Key Terms

  • Age-Sex distribution: A model used in population geography that describes the ages and numbers of males and females within a given population; also called a population pyramid. 
  • Agricultural density: The number of farmers per unit area of farmland. 
  • Arithmetic density: The number of people living in a given unit area. 
  • Baby Boom: A cohort of individuals born in the United States between 1946 and 1964, which was just after World War II in a time of relative peace and prosperity. These conditions allowed for better education and job opportunities, encouraging high rates of both marriage and fertility. 
  • Baby Bust: Period during the 1960s and 1970s when fertility rates in the United States dropped as large numbers of women from the baby boom generation sought higher levels of education and more competitive jobs, causing them to marry later in life. As such, the fertility rate dropped considerably, in contrast to the baby boom, in which fertility rates were quite high. 
  • Carrying capacity: The largest number of people that the environment of a particular area can sustainably support. 
  • Chain migration: The migration event in which individuals follow the migratory path of preceding friends or family members to an existing community. 
  • Child mortality rate: Number of deaths per thousand children within the first five years of life. 
  • Cohort: A population group unified by a specific common characteristic, such as age, and subsequently treated as a statistical unit. 
  • Cotton Belt: The term by which the American South used to be known, as cotton historically dominated the agricultural economy of the region. The same area is now known as the New South or Sun Belt because people have migrated here from older cities in the industrial north for a better climate and new job opportunities. 
  • Crude birth rate: The number of live births per year per thousand people. 
  • Crude death rate: The number of deaths per year per thousand people. 
  • Demographic accounting equation: An equation that summarizes the amount of growth or decline in a population within a country during a particular time period, taking into account both natural increase and net migration. 
  • Demographic transition model: A sequence of demographic changes in which a country moves from high birth and death rates to low birth and death rates through time. 
  • Demography: The study of human populations, including their temporal and ­spatial dynamics. 
  • Dependency ratio: The ratio of the number of people who are either too old or too young to provide for themselves to the number of people who must support them through their own labor. This is usually expressed in the form n:100, where n equals the number of dependents.
  • Doubling time: Time period required for a population experiencing exponential growth to double in size completely. 
  • Emigration: The process of moving out of a particular country, usually the individual person’s country of origin. 
  • Epidemiological transition: Sudden population growth as a result of improved food security and health care, followed by a plateau in growth because of subsequent declines in fertility rates. 
  • Exponential growth: Growth that occurs when a fixed percentage of new people is added to a population each year. Exponential growth is compound because the fixed growth rate applies to an ever-increasing population. 
  • Forced migration: The migration event in which individuals are forced to leave a country against their will. 
  • Generation X: A term coined by artist and author Douglas Coupland to describe people born in the United States between the years 1965 and 1980. This post-baby-boom generation will have to support the baby boom cohort as they head into their retirement years. 

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