Population: Concentration, Density & Growth

Answer (don’t copy) red questions What to write: Write blue words Answer (don’t copy) red questions

Purpose/Focus Describe regions where population is clustered and where it is sparse. Define three types of density used in population geography. Understand how to measure population growth through the nature increase rate. Understand how to measure births and deaths through CBR and CDR.

Where do geographers find our information? Census data (www.census.gov) Every 10 years Some aren’t counted. Take a guess: Who isn’t counted? What issues might occur when we don’t have 100% participation in the US census? Discuss at table Redistricting congressional districts happens every 10 years Sampling: what is it? Ruled unconstitutional in the US – why might sampling be a good or bad thing in the US? Nonparticipation groups include the homeless, ethnic minorities and undocumented immigrants – fear of legal implications if they participate. Sampling: selection of a subset of individuals from within a population used to estimate characteristics of the whole population. Supporters of sampling tend to have more concern for the homeless and immigrants (mostly Democrats in urban areas); those who oppose sampling are most likely from small towns and rural areas where there are fewer census data errors.

Population Concentrations Clusters – there are four major population clusters in the world. Where are they? Each cluster (except North America’s east coast and the Atlantic coast of Africa) contains close to ¼ of the world’s population. There are higher concentrations of people in rural areas in China, South Asia, Southeast Asia, and West Africa. In the other clusters most people are concentrated in urban areas.

Population Concentrations Sparse regions – Dry/Wet/Cold/High Why don’t people live there? Ecumene: the portion of Earth’s surface with permanent human settlement. ¾ of population lives on 5% of Earth The most sparsely populated regions are difficult to live in. However, the process of globalization has made it easier for people to live in all regions of the world. Image: Canada’s Population Ecumene, 2011

What major patterns do you notice on these maps? Global Ecumene 5000 BC-AD 1900 What major patterns do you notice on these maps? Where on Earth have people avoided living? Why? Why have previously uninhabited regions on Earth become more populated? There is a consistent progression from hunting and gathering to intensive settlement in Europe, Asia, North and South America, and portions of Africa. Areas avoided: deserts, mountains, and polar regions, but not necessarily the wet lands, especially in Africa.

Total number of objects (people) in an area Population Density 3 ways to measure density: Arithmetic Total number of objects (people) in an area (total population ÷ by land) Arithmetic density enables geographers to compare the number of people trying to live on a given piece of land in different regions of the world. It answers the “where” question of population. Comparing arithmetic and physiological density helps us understand the land’s capacity to provide food for the needs of the people. Physiological density tells geographers how many people the crops from one hectare of land must feed. Agricultural density shows how many farmers there are in a given area. Higher densities happen in less developed countries because they lack the technology and finance of developed countries. In other words, the equipment and wealth of farmers in developed countries is much higher than LDCs, so LDC farms require more manpower.

Arithmetic Density Simply the persons per square kilometer in the world. Only tells how densely populated each country is.

Population Density Physiological 3 ways to measure density Physiological Number of people supported by a unit area of arable land What is “arable?” Relationship between the size of a population and the availability of resources in a region Arithmetic density enables geographers to compare the number of people trying to live on a given piece of land in different regions of the world. It answers the “where” question of population. Comparing arithmetic and physiological density helps us understand the land’s capacity to provide food for the needs of the people. Physiological density tells geographers how many people the crops from one hectare of land must feed. Agricultural density shows how many farmers there are in a given area. Higher densities happen in less developed countries because they lack the technology and finance of developed countries. In other words, the equipment and wealth of farmers in developed countries is much higher than LDCs, so LDC farms require more manpower.

Physiological Density Tells a bit more about why the population is not uniformly distributed in the world. Relationship between people and arable land – how many people one kilometer of land has to feed.

Population Density Agricultural 3 ways to measure density Agricultural Ratio of the number of farmers to the amount of arable land Lower agricultural densities typically happen in developed countries because of technology and more money Arithmetic density enables geographers to compare the number of people trying to live on a given piece of land in different regions of the world. It answers the “where” question of population. Comparing arithmetic and physiological density helps us understand the land’s capacity to provide food for the needs of the people. Physiological density tells geographers how many people the crops from one hectare of land must feed. Agricultural density shows how many farmers there are in a given area. Higher densities happen in less developed countries because they lack the technology and finance of developed countries. In other words, the equipment and wealth of farmers in developed countries is much higher than LDCs, so LDC farms require more manpower.

Agricultural Density Tells how many farmers there are per square kilometer. More farmers does not necessarily mean more production. Example: US & Canada. Because there is higher level of technology and wealth, fewer farmers are required to farm more land.

More births than deaths - increase More deaths than births - decrease Population More births than deaths - increase More deaths than births - decrease

Live Births per year per 1,000 people CBR of 40 means… what? Crude Birth Rate (CBR) Live Births per year per 1,000 people CBR of 40 means… what?

Crude Birth Rate

Crude Birth Rate

Deaths per year per 1,000 people CBR of 50 means… what? Crude Death Rate (CDR) Deaths per year per 1,000 people CBR of 50 means… what?

Crude Death Rate

Crude Death Rate

Natural Increase Rate (NIR) Using what you already know about CBR & CDR, how do you figure out the NIR?

Natural Increase Graph: World Population through History What caused the world population to remain relatively constant for so long? Why does the world population increase so much in the 1800s? What might cause the world’s natural increase rate to be negative?

World Population Growth 1950-2011 Note the dramatic drop in annual population increase from the late 1950s through 1960. This IS NOT a dramatic decrease in the world population, just a drop in the annual increase and NIR.

Natural Increase Natural increase varies by individual country What areas of the world would you expect to have above average NIRs? What areas of the world would you expect to have negative NIRs? How does migration impact the data for countries?

Natural Increase Rate Current world average is 1.2. Africa and Southwest Asia tend to have higher than average NIRs. Many European countries have negative NIRs. Other “hot spots”?

Fertility Total Fertility Rate - average # of kids a woman has

Total Fertility Rate

Population Pyramids Shows the percentage (or number) of the total population in five-year age groups The shape of the pyramid indicates something unique about each population Wide at the bottom: high birth rate Wide at the top: older population Wide in the middle: population with either small families or no children

Population Pyramids: What are they telling you?

Dependency Ratio The larger the dependency ratio the greater the financial burden on those who are working to support the dependents. Europe’s dependency ratio = 47% (equal #s of young & elderly) Sub-Saharan Africa = 85% (young outnumber elderly 14:1) What kinds of social issues might arise from a large number of young dependents in a region? What issues might result from a large number of elderly dependents? Issues in sub-Saharan Africa include struggles to provide needed services like schools, hospitals and day-care centers. Elderly populations bring about social security issues (medical care, retirement funds, etc.)

Sex Ratio Developed countries have more females than males because women live an average of 7 years longer than men. Male babies outnumber female babies in Asian countries Why might Asian countries have a higher number of male babies? There is a possibility in Asian countries, such as China and India, that a large number of female babies are being aborted.

Natural Increase World population has been growing each year of the twentieth century by 1.2% All-time peak in NIR occurred in 1963 Swings in population growth can be impacted by only one- tenth of one percent in the NIR NIR impacts doubling time 1.2% NIR = doubling time of 54 years US NIR = .6 Is the doubling time in the US higher or lower than 54 years? If the NIR is higher, doubling time is lower

Fertility and Mortality CDR does not follow similar patterns to that of NIR, CBR, and TFR Combined CDR for developing countries is lower than that in developed countries Worldwide difference between high and low CDRs is much less than CBRs CDRs relate to the level of a country’s development

Population Structure Each country’s population varies over time. The pattern of a country’s population by age group is known as its population structure. Key Terms: Population Pyramid: a bar graph displaying a country’s distinctive population structure Dependency Ratio: number of people who are too young or too old to work, compared to the number of people in their productive years Sex Ratio: number of males per 100 females in the population

Components of Population Growth Key terms: Crude birth rate (CBR): # of live births in a year per 1,000 people Crude death rate (CDR): # of deaths in a year per 1,000 people Natural increase rate (NIR): percentage by which a population grows; CBR & CDR converted to percentages (numbers per 100): CBR% - CDR% = NIR [note: NIR does not take into account migration rates] Doubling time: number of years needed to double a population, assuming a constant rate of natural increase Total Fertility Rate (TFR): average number of children a woman will have throughout her childbearing years (15-49) Infant Mortality Rate (IMR): annual number of deaths of infants under one year of age, compared with total live births