Population introduction notes
Published on: Mar 4, 2016
Transcripts - Population introduction notes
Population geography is a division of human geography. It is the study of the ways in whichspatial variations in the distribution, composition, migration, and growth of populations arerelated to the nature of places. Population geography involves demography in a geographicalperspective. It focuses on the characteristics of population distributions that change in aspatial context. Examples can be shown through population density maps. A few types ofmaps that show the spatial layout of population are choropleth, isoline, and dot maps.Population geography studies: • Demographic phenomena (natality, mortality, growth rates, etc) through both space and time • Increase or decrease in population numbers • The movements and mobility of populations • Occupational Structure • Grouping of people in settlements • The way from the geographical character of places e.g. settlement patterns • The way in which places in turn react to population phenomena e.g. immigration • The following are definitions of some basic terms used frequently within population geography. • Natural Increase - The rate, at which a population increases, basically birth rate minus the death rate, and excluding immigration. This number is usually expressed per 1000 of the population, and may be expressed as a percentage. • Birth Rate- The number of births annually within a country or realm. Usually expressed by numbers of births per one thousand of the population, and may be expressed as a percentage. • Death Rates - The number of deaths annually within a country or region. Usually expressed by numbers of death per one thousand of the population, and may be expressed as a percentage. • Infant Mortality Rates - The number of deaths within a country or region, age 1 or below. Usually expressed by numbers of deaths per one thousand of the population, and may be expressed as a percentage. If infant mortality rates are considered in life expectancy rates and are high, it may impact the numbers significantly. • Life Expectancy Rates - The number of years a newborn can expect to live, calculated annually. Usually expressed as a percentage. • Population Density - The number of people per square mile or kilometer, usually takes total population of a country or region and total area. Can vary dramatically within a state, an example is density figures for Tokyo and all of Japan. • Double Time - The number of years it would take for a population to double in size if it continues to grow at the current rate. • Migration - permanent movement of the population. May be voluntary or forced. • Immigration- migration of the population from one sovereign state to another. • Out- Migration - movement of a population out of a sovereign state, usually a result of a lagging economy or civil strife. • Median Age - the middle or fiftieth percentile in regards to age within a population. • Average Age - the sum of all ages divided by the total number of the population.
Sex ratio is the demographic concept that measures the proportion of males to females in agiven population. It is usually measured as the number of males per 100 females. The ratio isexpressed as in the form of 105:100, where in this example there would be 105 males forevery 100 females in a population.Sex Ratio at BirthThe average natural sex ratio for humans from birth is approximately 105:100. Scientists arenot sure why there are 105 males born for every 100 females around the world. Somesuggestions for this discrepancy are given as:It is possible that over time, nature has compensated for males lost in war and otherdangerous activities to better balance the sexes.A more sexually active gender is more likely to produce offspring of their own gender. Thus,in a polygynous society (polygamy where one man has multiple wives), he is likely to have agreater proportion of offspring that are male.It is possible that female infants are under-reported and not registered with the government asoften as male babies.Scientists also say that a woman with a slightly over average amount of testosterone is morelikely to conceive a male.Female infanticide or the abandonment, neglect, or malnutrition of female infants in cultureswhere males are favored may occur.Today, sex-selective abortions are unfortunately common in countries like India and China.The introduction of ultrasound machines throughout China in the 1990s led to a sex ratio ofup to 120:100 at birth due to familial and cultural pressure to have ones only child as a male.Shortly after these facts became known, it became illegal for expectant couples to know thegender of their fetus. Now, the sex ratio at birth in China has been reduced to 111:100.The worlds current sex ratio is somewhat on the high side – 107:100.Total Fertility RateTotal Fertility Rate Impacts a Countrys PopulationThe term total fertility rate is used to describe the total number of children the average women in apopulation is likely to have based on current birth rates throughout her life. The number, which rangesfrom more than 7 children per woman in developing countries in Africa to around 1 child per woman inEastern European and highly-developed Asian countries.Associated with total fertility rate is the concept of replacement rate. The replacement rate isthe number of children each woman needs to have to maintain current population levels orwhat is known as zero population growth for her and her partner.
In developed countries, the necessary replacement rate is about 2.1. Since replacement cannot occur if a child does not grow to maturity and have their own offspring, the need for theextra .1 child (a 5% buffer) per woman is due to the potential for death and those who chooseor are unable to have children. In less developed countries, the replacement rate is around 2.3due to higher childhood and adult death rates.Nonetheless, with total fertility rates of 7.38 in Mali and 7.37 in Niger (as of mid-2007), theresultant growth in these countries populations is expected to be phenomenal over the nextfew years, unless growth rates and total fertility rates drop. For example, Malis 2007population is approximately 12 million. With its high total fertility rate per woman, Mali isexpected to grow to more than 15 million (a 3 million or 25% increase) by 2015! Malis 2007growth rate of 2.7 means a doubling time of just 26 years. Other countries with high totalfertility rates include Afghanistan at 6.64, Yemen at 6.49, and Samoa at 4.21.DEMOGRAPHIC TRANSITION MODELSummary of the theoryPopulation pyramids for 4 stages of the modelDemographic change in Sweden from 1735 to 2000. Red line: crude death rate (CDR), blue line:(crude) birth rate (CBR)
The transition involves four stages, or possibly five. • In stage one, pre-industrial society, death rates and birth rates are high and roughly in balance. • In stage two, that of a developing country, the death rates drop rapidly due to improvements in food supply and sanitation, which increase life spans and reduce disease. These changes usually come about due to improvements in farming techniques, access to technology, basic healthcare, and education. Without a corresponding fall in birth rates this produces an imbalance, and the countries in this stage experience a large increase in population. • In stage three, birth rates fall due to access to contraception, increases in wages, urbanization, a reduction in subsistence agriculture, an increase in the status and education of women, a reduction in the value of childrens work, an increase in parental investment in the education of children and other social changes. Population growth begins to level off. • During stage four there are both low birth rates and low death rates. Birth rates may drop to well below replacement level as has happened in countries like Germany, Italy, and Japan, leading to a shrinking population, a threat to many industries that rely on population growth. As the large group born during stage two ages, it creates an economic burden on the shrinking working population. Death rates may remain consistently low or increase slightly due to increases in lifestyle diseases due to low exercise levels and high obesity and an aging population in developed countries.As with all models, this is an idealized picture of population change in these countries. Themodel is a generalization that applies to these countries as a group and may not accuratelydescribe all individual cases. The extent to which it applies to less-developed societies todayremains to be seen. Many countries such as China, Brazil and Thailand have passed throughthe DTM very quickly due to fast social and economic change. Some countries, particularlyAfrican countries, appear to be stalled in the second stage due to stagnant development andthe effect of AIDS.Stage OneIn pre-industrial society, death rates and birth rates were both high and fluctuated rapidlyaccording to natural events, such as drought and disease, to produce a relatively constant andyoung population. Children contributed to the economy of the household from an early ageby carrying water, firewood, and messages, caring for younger siblings, sweeping, washingdishes, preparing food, and doing some work in the fields.Raising a child cost little more than feeding him: there were no education or entertainmentexpenses, and in equatorial Africa, there were no clothing expenses either. Thus, the total costof raising children barely exceeded their contribution to the household. In addition, as theybecame adults they became a major input into the family business, mainly farming, and werethe primary form of insurance in old age. In India an adult son was all that prevented a widowfrom falling into destitution. While death rates remained high there was no question as to theneed for children, even if the means to prevent them had existed.Stage TwoWorld population 10,000 BC - 2000 ADThis stage leads to a fall in death rates and an increase in population. The changes leadingto this stage in Europe were initiated in the Agricultural Revolution of the 18th century andwere initially quite slow. In the 20th century, the falls in death rates in developing countriestended to be substantially faster. Countries in this stage include Yemen, Afghanistan,Palestine, Bhutan and Laos and much of Sub-Saharan Africa (but do not include SouthAfrica, Zimbabwe, Botswana, Swaziland, Lesotho, Namibia, Kenya and Ghana, which havebegun to move into stage 3).
The decline in the death rate is due initially to two factors: • First, improvements in the food supply brought about by higher yields in agricultural practices and better transportation prevent death due to starvation. Agricultural improvements included crop rotation, selective breeding, and seed drill technology. • Second, significant improvements in public health reduce mortality, particularly in childhood. These are not so much medical breakthroughs (Europe passed through stage two before the advances of the mid-20th century, although there was significant medical progress in the 19th century, such as the development of vaccination) as they are improvements in water supply, sewerage, food handling, and general personal hygiene following from growing scientific knowledge of the causes of disease and the improved education and social status of mothers.A consequence of the decline in mortality in Stage Two is an increasingly rapid rise inpopulation growth (a "population explosion") as the gap between deaths and births growswider. Note that this growth is not due to an increase in fertility (or birth rates) but to adecline in deaths. This change in population occurred in northwestern Europe during the 19thcentury due to the Industrial Revolution. During the second half of the 20th century less-developed countries entered Stage Two, creating the worldwide population explosion that hasdemographers concerned today.Angola 2005Another characteristic of Stage Two of the demographic transition is a change in the agestructure of the population. In Stage One, the majority of deaths are concentrated in the first5–10 years of life. Therefore, more than anything else, the decline in death rates in Stage Twoentails the increasing survival of children and a growing population. Hence, the age structureof the population becomes increasingly youthful and more of these children enter thereproductive cycle of their lives while maintaining the high fertility rates of their parents. Thebottom of the "age pyramid" widens first, accelerating population growth. The age structureof such a population is illustrated by using an example from the Third World today.Stage ThreeStage Three moves the population towards stability through a decline in the birth rate. There are several factors contributing to this eventual decline, although some of them remainspeculative: • In rural areas continued decline in childhood death means that at some point parents realize they need not require so many children to be born to ensure a comfortable old age. As childhood death continues to fall and incomes increase parents can become increasingly confident that fewer children will suffice to help in family business and care for them in old age. • Increasing urbanization changes the traditional values placed upon fertility and the value of children in rural society. Urban living also raises the cost of dependent children to a family. • In both rural and urban areas, the cost of children to parents is exacerbated by the introduction of compulsory education acts and the increased need to educate children so they can take up a respected position in society. Children are increasingly prohibited under law from working outside the household and make an increasingly limited contribution to the household, as school children are increasingly exempted from the expectation of making a
significant contribution to domestic work. Even in equatorial Africa, children now need to be clothed, and may even require school uniforms. Parents begin to consider it a duty to buy children books and toys. Partly due to education and access to family planning, people begin to reassess their need for children and their ability to raise them.A major factor in reducing birth rates in stage 3 countries such as Malaysia is the availability of familyplanning facilities, like this one in Kuala Terenganu, Terenganu, Malaysia. • Increasing female literacy and employment lower the uncritical acceptance of childbearing and motherhood as measures of the status of women. Working women have less time to raise children; this is particularly an issue where fathers traditionally make little or no contribution to child-raising, such as southern Europe or Japan. Valuation of women beyond childbearing and motherhood becomes important. • Improvements in contraceptive technology are now a major factor. Fertility decline is caused as much by changes in values about children and sex as by the availability of contraceptives and knowledge of how to use them.The resulting changes in the age structure of the population include a reduction in the youthdependency ratio and eventually population aging. The population structure becomes lesstriangular and more like an elongated balloon. During the period between the decline in youthdependency and rise in old age dependency there is a demographic window of opportunitythat can potentially produce economic growth through an increase in the ratio of working ageto dependent population; the demographic dividend.However, unless factors such as those listed above are allowed to work, a societys birth ratesmay not drop to a low level in due time, which means that the society cannot proceed toStage Four and is locked in what is called a demographic trap.Stage FourThis occurs where birth and death rates are both low. Therefore the total population is highand stable. Some theorists consider there are only 4 stages and that the population of acountry will remain at this level. The DTM is only a suggestion about the future populationlevels of a country. It is not a prediction.
Countries that are at this stage (Total Fertility Rate of less than 2.5 in 1997) include: UnitedStates, Canada, Argentina, Australia, New Zealand, most of Europe, Bahamas, Puerto Rico,Trinidad and Tobago, Brazil, Sri Lanka, South Korea, Singapore, Iran, China, North Korea,Thailand and Mauritius.Stage FiveUnited Nations population projections by location.The original Demographic Transition model has just four stages, however, some theoristsconsider that a fifth stage is needed to represent countries that have undergone the economictransition from manufacturing based industries into service and information based industriescalled deindustrialization. Countries such as United Kingdom (the earliest nation universallyrecognised as reaching Stage Five), Germany, Italy, Spain, Portugal, Greece, and mostnotably Japan, whose populations are now reproducing well below their replacement levels,are not producing enough children to replace their parents generation. China, South Korea,Hong Kong, Singapore, Thailand and Cuba are also below replacement levels, but this is notproducing a fall in population yet in these countries, because their populations are relativelyyoung due to strong growth in the recent past.The population of southern Europe is already falling, and Japan and some of western Europewill soon begin to fall without significant immigration. However, many countries that nowhave sub-replacement fertility did not reach this stage gradually but rather suddenly as aresult of economic crisis brought on by the post-communist transition in the late 1980s andthe 1990s. Examples include Russia, Ukraine, and the Baltic States. The population of thesecountries is falling due to fertility decline, emigration and, particularly in Russia, increasedmale mortality. The death rate can also increase due to "diseases of wealth", such as obesityor diabetes, leading to a gradual fall in population in addition to above aging.Effects on Age StructureThe decline in death rate and birth rate that occurs during the demographic transition lead to aradical transformation of the age structure. When death rate is declined during the secondstage of the transition the result is primarily an increase in the child population. The reason isthat when death rate is high (stage one) the infant mortality rate is very high, often above 200deaths per 1000 children born. When death rate decline or improves, this, in general, resultsin significantly lower infant mortality rate and, hence increased child survival. Over time, ascohorts increased by higher survival rates get older, there will be an increase also in thenumber of older children, teenagers, and young adults. This implies that there is an increase
in the fertile population which, with constant fertility rates, will lead to an increase in thenumber of children born. This will further increase the growth of the child population. Thesecond stage of the demographic transition, therefore, implies and rise in child dependency.GLOSSARYge-Sex Pyramid (Population Pyramid): a series of horizontal bars that illustrate the structureof a population. The horizontal bars represent different age categories, which are placed oneither side of a central vertical axis. Males are to the left of the axis, females to the right.Ageing Population: In the population structure of many MEDCs there is often a highproportion of elderly people who have survived due to advances in nutrition and medicalcare. This creates problems since these people do not work and have to be provided withpensions, medical care, social support, sheltered housing etc. from the taxes paid by aproportionally smaller number of workers. In addition, an increasing number of young peopleare employed as careworkers for the elderly. This removes them from more productive jobswithin the economy and harms a countrys competitiveness.Ageing Population Structure: a population pyramid with a narrower shape, broad at the top,found in MEDCs. This reflects their low birth rates and the greater proportion of elderlypeople.Birth Rate: The number of live births per 1000 people per year.Bulge of Young Male Migrants: on a population pyramid; young males move to urban areasdue to push-pull factors.Census: a counting of people by the government every ten years to gather data for planning ofschools, hospitals, etc. This is unreliable for a number of reasons.Child Dependency ratio: the number of children in relation to the number of working(economically active) population, usually expressed as a ratio.Concentrated Population Distribution: where people are grouped densely in an urbanised area(see Port, Bridging-Point, Route Centre, Wet Point Site, Market Town, Mining Town,Resort).Contraception: using birth control to stop pregnancy.Counter-urbanisation movement of people in MEDCs away from urban areas to live insmaller towns and villages (see de-urbanisation and urban-rural shift).Death rate: the number of deaths per 1000 people per year.Demographic transition: the change from high birth rates and death rates to low birth ratesand death rates.Demographic Transition Model: diagram which shows the relationship between birth anddeath rates and how changes in these affect the total population.Dependency ratio: the ratio between those of working age and those of non-working age.This is calculated as:
% pop aged 0 -14 + % pop aged 65+ x 100 % of population aged 15-65Dependent Population: those who rely on the working population for support e.g. the youngand elderly.Depopulation: the decline or reduction of population in an area.De-urbanisation: the process in MEDCs by which an increasingly smaller percentage of acountry’s population lives in towns and cities, brought about by urban-rural migration. (SeeCounter-Urbanisation and Urban-Rural Shift).Dispersed Population Distribution: the opposite of a concentrated distribution; the populationmay be spread evenly over a fertile farming area, rather than concentrated in an urban centre.Dispersed population distributions tend to be of low density.Distribution (of a population): where people are found and where they are not found.Economic Migrant: person leaving her/his native country to seek better economicopportunities (jobs) and so settle temporarily in another country.Emigrant: someone who leaves an area to live elsewhere.Ethnic Group: the group of people a person belongs to categorised by race, nationality,language, religion or culture.Family Planning: using contraception to control the size of your family.Family Ties: the lack of family ties (no wife or children) encourages young males to migratefrom LEDCs to MEDCs or from rural to urban areas to seek a better life. The young (20-35)are also best-suited physically to heavy unskilled/semi-skilled work. See Guest-Worker.Fertile Age Group: the child-bearing years of women, normally 18-45 years of age.Ghetto: an urban district containing a high proportion of one particular ethnic group. Theterm ghetto comes from the district of Geto in medieval Venice which was reserved for Jews.Gross National Product (GNP) per capita: the total value of goods produced and servicesprovided by a country in a year, divided by the total number of people living in that country.Guest-Worker Migration: people leaving their country to work in another land but not tosettle: the term is associated with unskilled/semi -skilled labour.Human Development Index: a social welfare index, adopted by the United Nations as ameasure of development, based upon life expectancy (health), adult literacy (education), andreal GNP per capita (economic).Immigrant: someone who moves into an area from elsewhere.Infant Mortality: the number of babies dying before their first birthday per 1000 live births.Life Expectancy: the average number of years a person born in a particular country might beexpected to live.
Literacy Rate: the proportion of the total population able to read and write.Malnutrition: ill-health caused by a diet deficiency, either in amount (quantity) or balance(quality).Migrant: someone who moves from one place to another to live.Migration: movement of people.Model: a theoretical representation of the real world in which detail and scale are simplifiedin order to help explain reality.Natural Increase or Decrease: the difference between the birth rate and the death rate.Additional effects of migration are not included.Natural Population Change: the difference in number between those who are born and thosewho die in a year. Additional effects of migration are not included.Net Migration: the difference between the number of emigrants and the number ofimmigrants.New Commonwealth: the more recent members of Britain’s Commonwealth (ex-colonies,now independent), including countries such as India and Pakistan and the West Indianislands.Overpopulation: where there are too many people and not enough resources to support asatisfactory quality of life.Population Change: Births - Deaths + In-Migration - Out-Migration = Population Change.Population Density: number of people per square kilometre.Population Pyramid: a graph which shows the age and sex structure of a place.Push-Pull Factors: push factors encourage or force people to leave a particular place; pullfactors are the economic and social attractions (real and imagined) offered by the location towhich people move (i.e. the things which attract someone to migrate to a place).Quality of Life: things (e.g. housing) that affect your standard of living.Quality of Life Index: a single number or score used to place different countries in rank orderbased on their quality of life. Various indicators are included, e.g. GNP per person, calorieintake, life expectancy, access to health care, number of doctors per 100,000 etc.Racial Prejudice: thinking unpleasant things about people because of the colour of their skinand/or their ethnic group without knowing them.Racism: unfair, ridiculing or threatening behaviour towards someone because oi theirparticular racial group.Refugees: people forced to move from where they live to another area.Repatriation: a government policy of returning immigrants to their country of origin.Rural Depopulation: people leaving the countryside usually to live in towns (ie. rural-urbanmigration).
Rural Population Structure: young males move to urban areas due to push-pull factors. Thiscreates a characteristic indentation in the 20-35 age group population structure.Segregation: where immigrant groups such as Turks in Germany become increasinglyisolated in inner city areas, of poor housing (see ghetto).Sparsely Populated: an area that has few people living in it.Sterilisation: a method of contraception: in men an operation prevents sperm from beingreleased, and in women an operation stops the production of eggs.Structure (of a population): the relative percentages of people of different age groups, usuallyshown on a population pyramid.Urban-Rural Shift: the movement of people out of towns in MEDCs to seek a better qualityof life living in the countryside. Some work from home using telecommunicationstechnology; most travel into the city each day as commuters, contributing to the rush hour.Urbanisation: the growth of towns and cities leading to an increasing proportion of acountry’s population living there. It as a gradual process common in LEDCs where 1 millionpeople move from the countryside to the cities every three days.Urban Population Structure: young males move to urban areas due to push-pull factors. Thiscreates a characteristic population pyramid bulge in the 20-35 age range.Voluntary Migration: where people move to another area through choice.Working Population: people in employment who have to support the dependent population.Youthful Population: in the population structure of LEDCs, there is often a higher proportionof young people due to high birth rates and a reduction in infant mortality due to betternutrition, education and medical care. This may create problems since the children needfeeding, housing, education and eventually a job. Medical care and education has to be paidfor by taxing a proportionally small number of workers.Youthful Population Structure: seen as a wide base on population pyramids that reflect highbirth rates in LEDCs.