Population & Migration - AP Human Geography

In 2013, Mexico was the birthplace of the largest share of the United States of America's foreign born immigrant population, accounting for almost one-fourth of America's total foreign-born population.

This population pyramid would portrays the population of a college town. The large population within the 20 to 30 population group shows the presence of a university. A retirement community would have almost no one under the age of 55. Populations with high birth rates have pyramids with large bases, while populations with low birth rates are shaped like rectangles.

College towns have a higher population of males and females around the age of 20. There will be other age groups living in the town, but most of its population will be centered around that age.

The U.S. Census Bureau conducts a census every 5 years, in years ending in "2" and "7." This census, authorized by Title 13 in the U.S. Code, requires participation of all state and local governments in the United States. The first national census occurred in 1957.

The “centroid” refers to the geographic center of the population of a country. So, if more people in a country live in the West than in the East, the “centroid” will be further west. The “centroid” of the United States has moved consistently west and south basically since the country was founded. This is because a larger and larger share of the population is living in the West and the South. This is primarily a consequence of migration from the East to the West and from the North to the South.

The “Sun Belt” is the name used to describe much of the South and West of the United States. Beginning in the second half of the twentieth century, cities in these regions experienced dramatic population growth as many Americans migrated away from the Northeast and the Midwest. Chicago is a northern city, so it is not considered part of the “Sun Belt.”

A Push factor is a reason to leave a country while a pull factor is a reason to move to a country. If the country which someone is living in is at war, they are pushed to leave for fear of their life and livelihood, especially if their lives were particularly endangered.

While moving to a country that has more job opportunities is what often happens, this is a pull factor to pull someone to a country rather than a push factor which pushes someone out of a country.

Often the country that they are leaving is their native country and the country they are migrating to is foreign to them. If they are not living in their native country, that is not a push factor to leave although it could be a pull factor to return to their homeland.

Natural disasters are surprisingly not often considered in the process of migration. Even if they were taken into account, people would not purposefully migrate to a region that has more natural disasters than the region they are already in.

Someone who is forced to leave their home country is a refugee, regardless of what country to which they migrate.

An illegal immigrant is someone who illegally immigrates into a country that is not their home. If they illegally immigrated due to being forced to leave their country under persecution they claim refugee status and are classified as a refugee and not as an illegal immigrant.

There were many Soviet refugees during the break up of the U.S.S.R. and there still are many refugees who are Soviets. But the definition of a Soviet does not equal someone who is forced to migrate due to persecution. The definition of a Soviet is simply someone from the Soviet region of Eastern Europe and Western Asia.

A prisoner of war is not forced to leave their home country due to persecution. Rather, they are persecuted in a foreign country due to the war that is on-going. They are under captivity in a foreign country.

The “Great Migration” began in the late nineteenth century and continued throughout much of the early twentieth century. It involved the migration of African-Americans from the Deep South to cities like Chicago, Baltimore, Philadelphia, and New York - the industrial centers of the American northeast and midwest.

The geographic term “ecumene” is used to describe land that is permanently populated by human society. It can also refer to industrial and agricultural land that is permanently used to sustain the human population.

More than three-quarters of the world’s population lives in the developing world. The term “developing world” is generally used to refer to countries that do not have highly modernized and industrial economies.

Since roughly eight to ten thousand years ago, the population of humanity has climbed consistently, but gradually; however, beginning in the late eighteenth century in England, the Industrial Revolution changed everything. Technological, medical, and economic innovations have greatly increased the number of people that the planet can reasonably support. In the last two hundred years, the population has grown from one billion to over seven billion people.

China, India, Brazil, and Germany each have a larger population than the Netherlands, but they also all have much more land available in which to house that population. Remember, population density is based on the number of people divided by the land size. So a country with a large population and a small land size will have a very high population density. This is true of many European countries, particularly Northern European countries like Belgium, the Netherlands, and Great Britain. You might not have known the different population densities of these five countries, but you need to know that Northern Europe is an especially densely populated part of the world.

For most of human history, the population of Earth has climbed steadily and slowly, but in the eighteenth century (with the beginning of the Agricultural Revolution and the Industrial Revolution in Britain) the population began to grow dramatically. By the first decade of the nineteenth century, the population of Earth was around one billion for the first time in human history. In just over a century, the population would double again to two billion. The population is now in excess of seven billion and still climbing.

Population density refers to the number of people who live in a defined land area (usually square miles or square kilometers). So, if two million people live in ten square miles, the population density is two hundred thousand people per square mile. Population density is usually highest in urban areas, specifically cities like New York City, which keep growing but have a maximum land area. Los Angeles has a similar population level to New York City, but much more room for that population to inhabit. Of course, Los Angeles would still have a much higher population density than, say, the Rocky Mountains or the Alaskan wilderness.

A “primate city” is the largest city in a region. In order to be a “primate city” it must be disproportionately bigger than other cities in the region, primarily because those people who live in the surrounding area migrate to the “primate city” in search of work, education, or entertainment.

Oceania (which includes Australia, New Zealand, and many of the surrounding Pacific Islands) is by far the least heavily populated continent on Earth—excluding, obviously, Antarctica. Oceania has less than fifty million people living there. The next lowest—South America—has a population of four hundred million people.

China and India are the two most populous nations on Earth; each with over a billion people. China is currently the most populous nation in the world, but most experts agree that India will surpass China sometime in the next couple of decades due to India’s much faster rate of population growth.

The vast majority of population growth is taking place in the developing world. In recent years, more than ninety percent of population growth can be accounted for by countries in the developing world. These countries continue to grow to represent a larger and larger share of the world’s population.