Geography
Population Pyramid
A population pyramid is a graphical representation of a population's age and gender distribution. It consists of two bar graphs, one showing the percentage of males and females in different age groups. The shape of the pyramid provides insights into a population's demographic trends, such as birth rates, life expectancy, and overall population growth or decline.
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10 Key excerpts on "Population Pyramid"
eBook - PDF- Rodolfo B. Valdenarro(Author)
- 2020(Publication Date)
- Delve Publishing(Publisher)
The age distribution of the members of a population changes its age structure. Population age structure is represented in graphs known as Population Pyramids. 2.2.1. Population Pyramids Population Pyramids are a type of graph made up of stacked bars. The bars are horizontal. The proportion of the population is shown on the X-axis. The Y-axis depicts age-groups within the population. Usually, Population Pyramids do not indicate the actual figure of the members of a population. Rather, it shows the percentages of the population in the various age groups. Measures of central tendency must be put into use to enable accurate reading of Population Pyramids. A Population Pyramid helps make several deductions about a population such as birth rates, mortality rates, dependency ratios, and life expectancies. The dependency ratios of a population are established by determining the economically active members of a population and gauging the proportion against the less productive and unproductive members (Figure 2.1). Patterns of Population Composition 39 Figure 2.1. Dependency ratios of a population. Source: https://www.bbc.co.uk/bitesize/guides/ztr2w6f/revision/1. Population Pyramids vary in shape depending on the age distribution of the represented population. A triangular-shaped Population Pyramid represents a population that consists of a higher proportion of younger people. As such, a population is fast growing. A Population Pyramid that is column-shaped on the other hand, represents a population made up of a higher proportion of older people. Such a population is slow-growing (Rosset, 2017). 2.2.2. Types of Population Pyramids Population Pyramids come in three different types. 1. Expansive Pyramids: The first type is an expansive Population Pyramid. Expansive pyramids are used to represent populations whose larger percentage is made up of young people. There are two major characteristics that populations with a higher proportion of younger people portray.
eBook - PDFHuman Geography
People, Place, and Culture
- Erin H. Fouberg, Alexander B. Nash, Alexander B. Murphy, Harm J. de Blij(Authors)
- 2015(Publication Date)
- Wiley(Publisher)
A population’s “composi- tion” refers to the structure of that population in terms of age, sex, and other characteris- tics, such as marital status and education. One of the most common tools used by demog- raphers and geographers are Population Pyramids, which are used to visually illustrate a population’s age and sex distribution, key indicators of popula- tion composition. A Population Pyramid displays the percentages of each age group (normally five-year groups called “cohorts”) in the total population by a horizontal bar whose length represents that cohort’s share of the total population. Males in the group are to the left of the centre line, females to the right. A Population Pyramid can instantly convey the demo- graphic situation in a population or country. As Figure 4.11 demonstrates, in the poorer countries, where birth and death rates generally remain high, the pyramid resembles an ever- green tree, with wide branches at the base and short ones near the top. The youngest age groups have the largest share of the population; in the composite pyramids in Figure 4.11, the three groups up to age 14 account for more than 30 per- cent of the population. Older people, in the three highest age groups, represent only about 4 percent of the total. Slight variations of this pyramidal shape mark the population structure of such countries as Niger and Guatemala. From the 15-to-19 age group on, each group is smaller than the one below it. Population Pyramids A tool used to visually represent the age and sex composition of a population, in which the percentage of each age group (generally divided in five-year increments) is represented by a horizontal bar, the length of which indicates its relationship to the total population. The males in each age group are represented to the left of the centre line of each horizontal bar; the females in each age group are represented to the right of the centre line.
eBook - PDFPopulation Geography
Pergamon Oxford Geographies
- John I. Clarke, W. B. Fisher(Authors)
- 2013(Publication Date)
- Pergamon(Publisher)
An age-pyramid is rarely symmetrical, for, as we shall see in the next section, the sex-ratio differs from age to age. The preponderance of women in the older age-groups is usually clearly revealed in the age-pyramid. The word pyramid is only really appropriate for graphs of populations with a high proportion in the younger age-groups, but this still applies to the majority of world populations. In advanced communities age-p3n:amids have more varied and more complex forms. Certain basic tjrpes of pyramid may be distinguished. First, if a population has unchanging fertiUty and mortaUty it is a stationary population, and each step in the pyramid will differ from the one below only by the number of deaths at that age or age-group. If, however, the number of births increases from year to year, the population type will become progressive, and the pyramid will widen at the base; decline in the number of births will produce a regressive population with a pyramid which is narrow at the base and has the shape of a bell. Figure 13 presents six examples of contrasting age-pyramids at mid-century, ranging from that of 70 Population Geography - eo - 60 - 40 - 20 -O c A FEMALES MALES Ak FEMALES B R A Z I L - I 9 5 0 J A P A N -I 9 5 0 - eo - 60 40 20 Ο 80 60 -*o - 2 0 - O Ak Ak C A N A D A -1 9 5 0 U . S . A . -I 9 5 0 Ah G. B.- 1951 F R A N C E -1 9 5 0 IS 10 5 5 10 IS IS 10 S S 10 IS P E R C E N T A G E O F T O T A L M A L E O R F E M A L E P O P U L A T I O N A G E S A R E I N F I V E -Y E A R G R O U P S FIG. 13. Six age-pyramids at mid-century, contrasting yoimg and old popu-lations. The Population Pyramid of Great Britain in 1851 was not imlike that of Japan in 1950. Age-pyramids not only reflect long-term trends in fertility and mortality, they are also sensitive to the short-term eflfeas of wars, migrations, epidemics, baby-booms, population policies and other phenomena, and with practice one can interpret both the shape and the many irregularities in age-pyramids.
eBook - ePub- Andrew Hinde(Author)
- 2014(Publication Date)
- Routledge(Publisher)
Figure 13.2 ). Pyramids drawn using percentages are useful for comparing age and sex distributions, provided that the horizontal and vertical scales used in all the pyramids are the same.THE DEPENDENCY RATIOThis is a frequently used summary measure of the age and sex structure. It is defined as the ratio of economically inactive to economically active persons. In other words, it measures the number of inactive people whom each economically active person has to support.Since the economically inactive are mainly the young and the old, in practice the dependency ratio is calculated by dividing the total number of people under age a 1 and over age a 2 by the number of people between ages a 1 and a 2 Usually, a 1 is taken to be an age close to the school-leaving age, and a 2 an age close to the retirement age. In the United Kingdom, for example, a 1 = 16 years and a 2 = 60 or 65 years. The availability of data may determine the exact ages to be used in a particular population. In addition, it is possible to take a 2 to be different for males and females, if statutory retirement ages differ by sex.Figure 13.2 Population Pyramids for Uganda (1991) and Sweden (1995). Sources: United Nations (1995b, pp. 190–191); Statistics Sweden (1997, p. 40)An alternative measure of dependency is the proportion of the total population which is of working age (that is, aged between a 1 and a 2 ). This measure uses the same information as the dependency ratio, but is easier to understand.13.3 The demographic determinants of the shape of the Population Pyramid
Fertility and mortality both affect the shape of the Population Pyramid. Their effects are rather different from one another, however. FERTILITYThis has the most important effect in theory, and also often in practice. Its largely determines the width of the base of the Population Pyramid. High-fertility populations have pyramids which, when drawn using percentages, are wide at the base and narrow at the top (see the example of Uganda in Figure 13.2 ). Low-fertility populations tend to have a smaller percentage of children, and a correspondingly higher percentage of old people (see the example of Sweden in Figure 13.2
eBook - PDF- Rodolfo B. Valdenarro(Author)
- 2019(Publication Date)
- Delve Publishing(Publisher)
Figure 6.3: Agricultural density is defined as the field of study that explains the ration between, the farmers and the availability of the farmland in that area. Source: https://www.nps.gov/heho/learn/images/heho_aquatic_ monitoring_2014_2x1ratio.jpg?maxwidth=1200&maxheight=1200&autor otate=false Agricultural density is defined as the proportion that is available in a specified region of the number of the individuals who farm comparative to the amount of farmable land that is available. On the other hand, nutritional density is defined as the percentage among the total amount of farmland and total population of the area. Age/sex pyramids offer the graphic pictures comparative to the demographics of an area, a country, or a place. The areas with high birth rates as well as high expiry rates will generally have trilateral or triangular shaped pyramids, representing that the average age of the population of the area is young. On the other hand, the areas with lower birth rates as well as lower death rates will not have triangular shaped pyramid, but it will have Population Pyramids with sides that are far more vertical, thus representing that the average age of population of the area is higher. The average age of a population (number of youth individuals comparative to number of older Applied Human Geography 126 individuals) is usually a dependable pointer of area’s potential for natural (not counting immigration) growth of population. If most of the population of an area is in the child-bearing years or younger, the potential for the development is great. On the other hand, if the popula-tion of an area is normally older, the population’s potential growth is lesser.
eBook - ePubDemography at the Edge
Remote Human Populations in Developed Nations
- Rasmus Ole Rasmussen, Prescott Ensign, Lee Huskey, Dean Carson(Authors)
- 2016(Publication Date)
- Routledge(Publisher)
Chapter 2 ). Missing data about a relatively small number of people will have large effects on the shape of age pyramids. As with all studies of remote populations, therefore, age data is difficult to interpret ‘from a distance’ unless the researcher knows about data issues and can hypothesise about the events leading to specific bubbles and craters. Demography, history and local knowledge are inextricably linked in the case examples presented in this chapter.Demographic transition theories describe a change in the shape of age pyramids over time from those resembling triangles to those resembling ‘coffin’ or ‘cigar’ shapes – a much more even distribution of the population across ages (Banks 2008). The even distribution sees median ages rise as there are proportionally fewer children and proportionally more older people. It is the progression of working-age people (either 15–64 years or 20–64 years depending on who is doing the measuring) into older age groups that has been a focus of literature examining the ‘ageing crisis’ in developed nations. The ‘crisis’ is the increased expense of health care and other services required by older people coupled with the loss of productivity resulting from reduced proportion of people in the labour force (Jackson 2006). Not all analysts agree that ageing of this type inevitably presents an economic ‘crisis’ (Werblow et al. 2007), however the implications for the health care system (irrespective of how the system is funded) are generally agreed.The progression of substantial proportions of people into post working-age groups has been a topic of concern in remote Australia (Larson 2006) and Europe’s northern sparsely populated areas (Manthorpe and Livsey 2009) and the subject of extensive planning in Alaska (Alaska Department of Health and Social Services 2007a, 2007b). Emma Lundholm and Dieter Müller’s case example in this chapter revisits the situation in the European North, noting that age-differentiated migration patterns (young people are more likely to leave than old people) are one of the key underlying factors in that context. A crater appears in the working age group, with over-representation of the very young and of the old. They also note the influence of amenity in-migration in some regions. Much of the amenity migration into these regions is by post working-age people who are ‘multi-residential’ – they have homes in more than one location. In many cases, the bubbles created by amenity migrants are hidden in formal data collections (see Chapter 2
eBook - ePubDemographics
A Guide to Methods and Data Sources for Media, Business, and Government
- Steven H. Murdock, Chris Kelley, Jeffrey L. Jordan, Beverly Pecotte, Alvin Luedke(Authors)
- 2015(Publication Date)
- Routledge(Publisher)
Chapter 2 Basic Concepts, Definitions, and Geography of Demography As with any area of study, it is essential in demography to understand its basic concepts and the definitions of its key terms and to become familiar with the types of geographic areas for which demographic data are generally available. Knowing the jargon of demography and knowing the types of areas for which data can be obtained are essential first steps in knowing how to effectively use its data. In this chapter, we provide an overview of key concepts and definitions and examine the geographic bases used in demography and its applications. Basic Dimensions and Processes Given the definition of demography as the study of population size, distribution, and composition and of the processes that determine these, a logical place to begin in understanding demographic factors is to understand (1) what is meant by a population; (2) the three key dimensions of population–size, distribution, and composition; and (3) the three basic processes that determine population change–fertility, mortality, and migration. A population refers to the persons living in a specific area at a specific point in time. It refers to the aggregate, the group of people as a whole, in an area. As such, it has characteristics that are unique to an aggregate and are not just the sum of individuals’ traits or characteristics. For example, a population can have a death rate, birth rate, etc., but individuals are either alive or dead, have or have not been born. There is no death or birth “rate” for an individual
eBook - PDF- R. Knowles, J. Wareing(Authors)
- 2014(Publication Date)
- Made Simple(Publisher)
PART TWO : POPULATION GEOGRAPHY CHAPTER FIVE POPULATION DISTRIBUTION Until quite recently the systematic study of population had been largely neglected by geographers, in contrast with other fields of human geography such as agriculture, industry and settlement which have a long-established tradition of systematic analysis. However, in recent years there has been a growing awareness of the importance of population studies within the broad framework of human geography. Population geography has rapidly advanced from a peripheral position within the discipline to the stage where it has been claimed that 'numbers, densities and qualities of the population provide an essential background for all geography. Population is the point of reference from which all the other elements are observed and from which they all, singly and collectively, derive significance and meaning. It is population which furnishes the focus.* (G. T. Trewartha) Population geography is concerned with the study of demographic processes and their consequences in an environmental context. It may thus be distin-guished from demography by its emphasis on the spatial variations in the growth, movement and composition of populations, and its concern with the social and economic implications of these variations. The development of the subject has been severely limited by a lack of demographic data for many parts of the world, but, like other branches of geography, it is concerned with description, analysis and explanation, although a large part of the work to date has been concerned with population mapping and descriptive studies, simply in order to establish the data base which must precede analysis. Sources of Population Data One of the most difficult problems facing the population geographer is the varied quality of population data available for different countries and regions of the world.
eBook - PDFPopulation
Analysis and Models
- Louis Henry(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
This series, however, is still too complicated; so the first step in the analysis of an age distribution or age structure, is a division into broad age groups. In practice, the two following distributions are most used: 0-14, 15-64, 65 years and over (children, persons of working ages, old people); 0-19, 20-59, 60 years and over (young people, adults, old people). Table 2.3 presents a few figures for France based on the latter distribution: Table 2.3 Population distribution in broad age groups: France, selected dates Age 1776* 1851 1901 1936 1954 1968 0-19 years 428 370 346 302 307 338 20-59 years 500 531 530 551 531 484 60 years and over 72 99 124 147 162 178 Total 1000 1000 1000 1000 1000 1000 * Estimate Note the increase in the proportion of old people, and the simultaneous decrease in the proportion of young people up to 1936; this is the phenomenon of ageing which occurs when the birth rate of a population is declining. We will come back to this later. c) The Age pyramid The graphical presentation called the 'age pyramid' gives a good overall view of the age distribution of a population. We plot age on the vertical axis, and numbers on the horizontal axis (there are two horizontal readings, for males on the left, and for females on the right). The numbers refer to a specified age interval, most often one year. Each age interval, whether one year or more, is represented by a rectangle with an area proportional to the size of the group. The height of this rectangle is proportional to the number of years in the age Analysis of census data 15 interval, and the length is proportional to the size of the group divided by the same number of years. Suppose, for example, that we must present the age distribution of the French population on 1 January 1968, assuming that it is given by single years up to 19 years of age and by 5-year age groups for ages 20 and over (the figures are taken from table 2.4).
- Guo Zhigang, Wang Feng, Cai Yong(Authors)
- 2017(Publication Date)
- Routledge(Publisher)
Not only were the bipolar bulges present in the age pyramid, they also led to a higher ratio of total dependency compared to the urban population. The absolute number of dependents, elderly or junior, was also much higher than that in urban areas. The urban-rural Population Pyramid in Figure 9.7 illustrates several conclusions: first, the distribution of young laborers in China has more weight in cities and towns; second, more than half of the women of childbearing age in China already reside in a city or town; third, the burden of the rural elderly is heavier, in both population size and dependency ratio, compared to the urban burden. These have important implications for national economic and population renewals. Another important implication we can draw from Figure 9.7 is the relative change in the population size of children compared to that of the working-age. Children are the reserves for the two renewals of production and reproduction, and the relative changes in scale can reveal future prospects. As shown in Figure 9.7, in the current rural residents, the juvenile age groups had slightly smaller, yet comparable populations to the working-age groups. However, the current situation in rural areas is post out-migration of large numbers of laborers. The comparable number of the juvenile population is itself suggestive of an unsustainable future of continuous out-migration of laborers, since the system of supporting the elderly in rural areas would collapse. On the other hand, the pronounced concavity in urban juvenile groups suggests a great need for future in-migration of laborers to maintain normal socioeconomic development
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