Population distribution - is the pattern of human settlement the spread of people across the earth

Population density - is a measure of the average population per square mile or kilometer of a an area

Midlatitudes - the regions between 30 degrees and 60 degrees, north and south of the equator

Low-lying areas - Most people live in low-lying areas rather than high altitude areas such as mountains

Other factors - most people live near lakes or rivers

Social stratification - the differentiation of society into classes based on wealth, power, production, and prestige

Arithmetic population - the most commonly used population density

Physiological population density - calculated by dividing population by the amount of arable land, or land suitable for growing crops

Agricultural population density - compares the number of farmers to the area of arable land

Redistricting - because urban area are continuing to increase in population and the population of rural area is shrinking these boundary adjustments

Infrastructure - refers to the facilities and structures that allows people to carry out their typical activities

Overpopulation - having more people than it can support is partially dependent on it population distribution and density

Carry capacity - the number of people a region can support without damaging the environment

The Influence of Time - The carrying capacity of a region can change over time

Influence on Cities - cities could be built on land with low carrying capacity, such as where the soil is not ideal for farming

Significance of Density - In addition to agriculture many other aspects of the environment are affected as population density increases

Population Pyramid - one of the most useful tools to study population is the age sex composition graph

Birth deficit - this slowdown of births

Baby boom - the birth rate spikes

Baby bust - birth rates lower for a number of years

Potential workforce - people ages 15-64

Dependent workforce - people under the age 15 and over 64

Dependency ratio - the comparison between the size of these two groups

Demographic balancing equation - future population = Current population + (number of births - umber of deaths) + (number of immigrants - number of emigrants)

Crude birth rate (CBR) - is the number of live births per year for each 1,000 people

Total fertility rate (TFR) - is the average number of children who would be born per woman of that group in a country

Life expectancy - the average number of years people live

Sewer Systems - one of the most important advances in reducing mortality was the creation fo sewer systems

Water and Waste Systems - people also learned that boiling water before they used it could prevent transmission of waterborne illnesses

Vaccines - today efforts by the United Nations, national governments and private organizations to vaccines against other serious diseases such as polio, tuberculosis, and rabies

Antibiotics - while vaccines helped prevent people from getting ill antibiotics helped cure people who had bacterial infections

Better Medical Care - improved medical procedures have also extended life expectancy

Crude death rate (CDR) - of an area are measured per 1.000 population

Rate of Natural Increase (RNI) - the percentage at which a country’s population is growing or declining without the impact of migration

Population Doubling Time - can be estimated using an equation known as the rule of 70 (some people use rule of 72)

Demographic Transition Model (DTM) - shows five typical stages of population change that countries experience as they modernize

Demographic moment - this process occurs because even though fertility rates have declined people are living longer and this results in population continuing to grow for another 20-40 years

Epidemiological Transition model - this model is an extension of the demographic transition model and explains that changing death rates and more common causes of death within societies

Malthusian Theory - geographers and other social scientists have debated the usefulness of Mathus’s ideas about population growth

Boserup Theory - suggested that the more people there are, the more hands there are to work, rather than just more mouths to feed

Neo-Malthusians - there are those who still accept his fundamental premise as correct today,

Gender preference - chinese culture has long preferred male children over females, so the one child policy contributed to an unbalanced gender ratio

Pronatalist policies - designed to increase the fertility rate

Demographic balancing equation - includes both immigrants and emigration when predicting future population

Dependent population - because they are considered too young or too old to work full time

Migration - is the permanent or semipermanent relocation of people from one place to another

Voluntary migration - most people who move do so in search of a better life

Migration Transition Model - Geographers such as Wilbur Zelinsky saw a connection between Zelinsky’s theory

Intervening Obstacles - barriers that make reaching their desired destination more difficult

Intervening opportunities - migrants may also encounter opportunities en route that disrupt their original migration plan

Short Distances - most migrants travel only a short distance. The further apart two places are, the less likely it is that people will migrant between those places also called distance decay

Urban Areas - migrants traveling long distances usually settle in large urban areas

Gravity model of migration - the model assumes that the size and distance between two cities or countries will influence the amount of interactions that include migration, travel, and economic activity

Multiple steps - most migration occurs through step migration a process in which migrates reach their eventual destination through a series of smaller moves

Rural to urban - most migration in history has been from rural agricultural areas to urban city areas

Counter migration - each migration flow products a movement in the opposite direction

Return migration - immigrants moving back to their former home

Youth - most immigrants are younger adults, between ages 20 and 45

Gender Patterns - most international migrants are young males,  while more internal migrants are females

Forced Migration - migration that is involuntary meaning migrants have no choice but to move

Internally displaced person (IDP) - if these migrants move to another part of the same country they are called

Refugees - if they cross international borders

Asylum - is protection granted by one country to an immigrant from another country who has legitimate fear of harm or death if he or she returns

Internal migration - is used to describe movement that occurs within a country

Transnational migration - is when people move from one country to another or internationally rather than internally

Chain migration - explains many patterns of migration and helps migrates transition into the receiving country

Guest workers - are also transnational migrants who relocate to a new country to provide labor that isn't available locally

Transhumance - the process of herders moving with their animals to different pastures during different seasons

Homestead Act - a program in which the U.S government gave land to settlers willing to stay and farm it for five years

Current Immigration Policies - today many governments regulate the flow of workers into their country

Guest worker policies - these regulate the number of workers who can temporarily enter each country to work in specific industries for a defined amount of time

Family reunification - policies that allow migrants to sponsor family members who migrate to the country

Xenophobia - a strong dislike of people of another culture

Benefits of Migration -  since immigrants generally move from poorer regions to wealthier areas they often can afford to make remittances money sent to their family and friends in the country they left

Cost of migration - Migrations can also have negative effects on the places people are leaving

Brain drain - when migrantation out of country is made up of many highly skilled people

Ethnic enclaves - or neighborhoods filled primarily with people of the same enthnic group such as Little Italy or Chinatown add to cultural richness of countries in which they develop