AP Human Geography Unit 2
3.1 Where people live
Clustered populations are grouped together around a central point.
linear pattern describes a population that appears to form long and narrow lines
dispersed is when population is spread out without any order.
Physical and environmental factors
humans more likely to settle where there are moderate climates, rich soils, and adequate water supplies.
Coasts and waterways are often densely populated because they offer economic advantages and convenient transportation route
Climate
climate: long term patterns of weather in an area.
temperate climates: moderate temperatures and adequate precipitations amounts are usually more densely populated
Landforms
landforms: natural features of earth’s surface also influence population distribution. people prefer lowlands due to the ease of building, planting corps, and transportation goods.
In China, a number of physical and environmental factors, including water accessibility, influence population. Population distribution in China has remained relatively steady over time. The country has an enormous -though unevenly distributed-population.
One historically significant example of migration influenced by economic factors includes the movement of Europeans to North and South America, Africa, Australia, and New Zealand as part of imperialism and colonialism in the late 1800s and early 190s.
Measuring population density
Arithmetic density: measures total number of people per unit area of land. calculated by dividing the total population by total land area → it does not account for land that is difficult to live on or uninhabitable.
Though Taiwan has one of the highest population densities in the world, about 75 percent of its people live on just one-third of its land area. Roughly 30 percent of Taiwan's entire population lives in the greater urban area of Taipei, its largest city.
Physiological density: total number of people per unit of arable land, which is land that can be used to grow corps.
One country with greatly varying arithmetic and physiological densities is the United Arab Emirates (UAE). These densities differ due to the country's lack of arable land. The United Arab Emirates is located within an arid region, and nearly the entire country is desert.
Agricultural density
agricultural density measures total number of farmers per unit of arable land.
The highest agricultural densities are found in parts of Asia. Agricultural density can reveal more about a country's wealth than its population distribution.
A higher agricultural density, in which there are high numbers of farmers per land unit, suggests that most of the farming taking place is providing crops and livestock for only the farmers families and close community → Subsistence agriculture.
3.2 Consequences of population distribution
Social services are more efficient when population distribution is clustered because the operating costs of services such as police, fire, medical, and waste collection are lower when serving a smaller, densely populated geographic area.
In areas where populations are clustered, for example, fires can pose a bigger threat to more inhabitants.
Carrying capacity: maximum population size an environment can sustain.
3.3 Population composition
dependency ratio: number of people in dependent age group (under age of 15 and age of 65 and up) divided by the people in the working age group multiplied by 100.
A higher dependency ratio indicates fewer people of working age and fewer people in the workforce earning income and paying taxes.
This means that in a country with a high dependency ratio, people of working age-and the overall economy —encounter greater pressures in supporting the aging and youthful population groups.
Ideally, an economy should have a smaller dependency ratio, with a constant flow of people entering the workforce and a smaller number exiting the working-age population each year.
Sex ratio
Geographers also study a population's sex ratio when evaluating population composition.
→ sex ratio the proportion of males to females in a population.
In peripheral countries, the number of women who die during childbirth contributes to a lower percentage of women.
3.4 Measuring growth and decline
Crude brith rate (CBR) is the number of births in a given year per 100 people in a given population.
The global CBR in 2018 was estimated at 18.2 births per 1,000, with core regions having an average CBR of 11.1 and peripheral regions having a much higher average CBR of 21.3.
A potentially more informative measure is the total fertility rate (TFR), which is the average number of children one woman in a given country or region will have during her childbearing years, which are ages.
In 2017, the global average fertility rate was just below 2.5 children per woman. But in semi-peripheral and peripheral countries, the rate can be 5.0 or higher, and in core countries, it's often 2.0 or less.
→ A population's replacement level is the number of children per woman necessary to keep a country's population constant. A level of 2.1 is the point at which a population is neither growing nor declining but remains stable.
Infant mortality rate (IMR) is the number of deaths of children under the age o f 1 per 1,000 live births.
4.1 why populations grow and decline
rate of natural increase (RNI) is the difference between the crude birth rate (CBR) and crude death rate (CDR) of a defined group o f people.
→ doubling time (DT): is the number of years in which a population growing at a certain rate will double 70/RNI = DT.
Birth rates tend to decline in times of economic hardship, particularly if people are concerned about having sufficient food and resources to support their children.