ibdp!ess!topic!3.1! popula’on)dynamics)0)the)shape)of ... ·...
TRANSCRIPT
Popula'on dynamics -‐ the shape of things to come!Please read Chapter 8 from the ESS Course Companion while comple4ng this study guide. There are 28 numbered ques4ons requiring a response. Keep this guide throughout your study of Topic 3 -‐ you will find it useful when preparing for your test!
Objec've:In this study guide, you will:
· Describe the paGern of human popula*on growth.· Explain exponen*al growth and its implica4ons for human popula4on· Review popula4on growth models and carrying capacity in the biosphere.· Interpret popula*on pyramids· Describe the demographic transi*on model· Discuss the use of models to predict popula4on growth.· Calculate crude birth rate, crude death rate, fer*lity, doubling *me and natural increase rate.· Draw a popula4on pyramid from given data.· Iden4fy demographic transi4on stages from popula4on pyramids.
Human popula'on growthDemography is the study of the sta4s4cal characteris4cs of human popula4ons, e.g. total size, age and sex composi4on, and changes over 4me with varia4ons in birth and death rates.
1. Use Table 1 below to plot a human popula*on growth curve from 1000 AD to the present on the grid provided. Your graph should be scaled appropriately and include labels and units of measurement for both the x-‐axis and y-‐axis.
Table 1: Human popula'on (in billions) from 2000 years before present un'l 2055
Date Pop. Date Pop. Date Pop. Date Pop. 1000 0.40 1927 2.00 1974 4.00 2010 6.801500 0.50 1950 2.50 1980 4.50 2013 7.001804 1.00 1960 3.00 1987 5.00 2028 8.001880 1.50 1970 3.50 1999 6.00 2055 9.00
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Exponen4al growth is characterised by increasingly short doubling 4mes. Doubling *me is the number of years it would take to double the size of a popula4on at a par4cular rate (%) of growth. For example, with a 2% growth rate or natural increase rate, the popula4on doubling 4me would be about 35 years, with 4% natural increase rate a popula4on will double in about 17 years.
2. How long would it take for a popula4on to double if the natural increase rate was 1%?
Answer: ………… years.
3. Use Table 1 to calculate the doubling 4mes for the global human popula4on since 1500 AD.Date popula'on doubling 'me
(years) date popula'on doubling 'me
1500 0.5 1500 5.01800 1.0 300 6.01927 2.0 7.0
3.0 8.04.0 9.0
Exponen*al Growth
Read The Persian Chessboard, the ar4cle on exponen4al increase by Joseph Fourier, and answer the ques4ons which follow.
THE PERSIAN CHESSBOARDby JOSEPH FOURIER,
Analy7c Theory of Heat, Preliminary Discourse (1822)
The way I first heard the story, it happened in ancient Persia. But it may have been India or even China. Anyway, it happened a long 4me ago. The Grand Vizier, the principal advisor to the King, had invented a new game. It was played with moving pieces on a square board comprised of 64 red and black squares. The most important piece was the King. The next most important piece was the Grand Vizier-‐just what we might expect of a game invented by a Grand Vizier. The object of the game was to capture the enemy King, and so the game was called, in Persian, shahmat-‐shah for King, mat for dead. Death to the King. In Russian it is s4ll called shakhmat, which perhaps conveys a lingering revolu4onary sen4ment. Even in English there is an echo of this name-‐the final move is called "checkmate." The game, of course, is chess. As 4me passed, the pieces, their moves, and the rules of the game all evolved; there is, for example, no longer a Grand Vizier-‐it has become transmogrified into a Queen, with much more formidable powers.
Why a King should delight in the inven4on of a game called "Death to the King" is a mystery. But, so the story goes, he was so pleased that he asked the Grand Vizier to name his own reward for so splendid an inven4on. The Grand Vizier had his answer ready: He was a modest man, he told the Shah. He wished only for a modest reward. Gesturing to the eight columns and eight rows of squares on the board he had invented, he asked that he be given a single grain of wheat on the first square, twice that on the second square, twice that on the third, and so on, un4l each square had its complement of wheat. No, the King remonstrated, this is too modest a reward for so important an inven4on. He offered jewels, dancing girls, palaces. But the Grand Vizier, his eyes becomingly lowered, refused them all. It was liGle piles of wheat that he craved. So, secretly marvelling at the humility and restraint of his counsellor, the King consented.
When, however, the Master of the Royal Granary began to count out the grains, the King faced an unpleasant surprise. The number of grains starts out small enough: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 . . . but by the 4me the 64th square is approached, the number of grains becomes colossal, staggering. In fact, the number is nearly 18.5 quin4llion. Perhaps the Grand Vizier was on a high-‐fibre diet.
How much does 18.5 quin4llion grains of wheat weigh? If each grain is a millimetre in size, then all of the grains together would weigh around 75 billion metric tons, which far exceeds what could have been
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stored in the Shah's granaries. In fact, this is the equivalent of about 150 years of the world's present wheat produc4on. An account of what happened next has not come down to us. Whether the King, in default, blaming himself for inaGen4veness in his study of arithme4c, handed the kingdom over to the Vizier, or whether the laGer experienced the tribula4ons of a new game called viziermat, we are not privileged to know.
The story of the Persian Chessboard may be just a fable. But the ancient Persians and Indians were brilliant pathfinders in mathema4cs, and understood the enormous numbers that result when you keep on doubling. Had chess been invented with 100 (10 X 10) squares instead of 64 (8 X 8), the resul4ng debt in grains of wheat would have weighed as much as the Earth. A sequence of numbers like this, where each number is a fixed mul4ple of the previous one, is called a geometric progression, and the process is called an exponen7al increase.
Exponen4als show up in all sorts of important areas, unfamiliar and familiar. The most common circumstance in which repeated doublings, and therefore exponen4al growth, occurs is in biological reproduc4on. Consider first the simple case of a bacterium that reproduces by dividing in two. Aner a while, each of the two daughter bacteria divides as well. As long as there's enough food and no poisons in the environment, the bacterial colony will grow exponen4ally. Under very favourable circumstances, there can be a doubling every 15 minutes or so. That means 4 doublings an hour and 96 doublings a day. Although a bacterium weighs only about a trillionth of a gram, its descendants, aner a day of wild asexual abandon, will collec4vely weigh as much as a mountain; in a liGle over a day and a half as much as the Earth; in two days more than the Sun. . . . And before very long, everything in the Universe will be made of bacteria. This is not a very happy prospect, and fortunately it never happens. Why not? Because exponen4al growth of this sort always bumps into some natural obstacle. The bugs run out of food, or they poison each other, or are shy about reproducing when they have hardly any privacy. Exponen4als can't go on forever, because they will gobble up everything. Long before then they encounter some impediment.
Exponen4als are also the central idea behind the world popula4on crisis. For most of the 4me humans have been on Earth the popula4on was stable, with births and deaths almost perfectly in balance. This is called a "steady state." Aner the inven4on of agriculture including the plan4ng and harves4ng of those grains of wheat the Grand Vizier was hankering for-‐-‐the human popula4on of this planet began increasing, entering an exponen4al phase, which is very far from a steady state. Right now the doubling 4me of the world popula4on is about 40 years. Every 40 years there will be twice as many of us. As the English clergyman Thomas Malthus pointed out in 1798, a popula4on increasing exponen4ally-‐Malthus described it as geometrical progression-‐will outstrip any conceivable increase in food supply. No Green Revolu4on, no hydroponics, no making the deserts bloom can beat an exponen4al popula4on growth.
There is also no extraterrestrial solu4on to this problem. Right now there are something like 240,000 more humans being born than dying every day. We are very far from being able to ship 240,000 people into space every day. No seGlements in Earth orbit or on the Moon or on other planets can put a percep4ble dent in the popula4on explosion. Even if it were possible to ship everybody on Earth off to planets of distant stars on ships that travel faster than light, almost nothing would be changed, all the habitable planets in the Milky Way galaxy would be full up in a millennium or so. Unless we slow our rate of reproduc4on. Never underes4mate an exponen4al!
4. Write a defini4on of exponen*al growth:
5. What is the trend in the changing doubling 4mes over the past 2000 years?
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Exponential growth and implication for the human populationThere are two main theories rela4ng to popula4on growth and food supply, namely Malthus and Boserup.
Malthusian theoryThomas Malthus was an English clergyman and economist who lived from 1766 to 1834. In his text An essay on the principle of popula4on, 1798, Malthus expressed a pessimis4c view over the dangers of over-‐popula4on and claimed that food supply was the main limit to popula4on growth. Malthus believed that the human popula4on increases geometrically (i.e. 2, 4, 8, 16, 32, etc.) whereas food supplies can grow only arithme4cally (i.e. 2, 4, 6, 8, 10, 12, etc.) being limited by available new land. Malthus added that the 'laws of nature' dictate that a popula4on can never increase beyond the food supplies necessary to support it.According to Malthus, popula4on increase is limited by certain 'checks'. These prevent numbers of people increasing beyond the op4mum popula4on, which the available resources cannot support. As long as fer4le land is available, Malthus believed that there would be more than enough food to feed a growing popula4on. However, as popula4on and the demands for food increase, there is a greater pressure to farm more intensively and cul4vate poorer, more marginal land. According to Malthus, though, food produc4on can only increase to a certain level determined by the produc4ve capacity of the land and exis4ng levels of technology. Beyond the ceiling where land is used to its fullest extent, over cul4va4on and, ul4mately, soil erosion occurs, contribu4ng to a general decline in food produc4on. This is known as the law of diminishing returns where, even with higher levels of technology, only a small increase in yield will eventually occur. These marginal returns ul4mately serve as a check to popula4on growth. Malthus did acknowledge that increases in food output would be possible with new methods in food produc4on, but he s4ll maintained that limited food supply would eventually take place and so limit popula4on.
Limita*ons of Malthusian theoryAn4-‐Malthusians cri4cise the theory as being too simplis4c. A shortage of food is just one possible explana4on for Malthus’ reasoning (geometric popula4on growth which outruns an arithme4c increase in food supply). This ignores the reality that it is actually only the poor who go hungry. Poverty results from the poor distribu4on of resources, not physical limits on produc4on. Except on a global scale, the world's community is not 'closed' and so does not enjoy a fair and even distribu4on of food supplies. Even so, Malthus could not possibly have foreseen the spectacular changes in farming technology which mean we can produce enough food from an area the size of a football pitch to supply 1000 people for a year, i.e. there is enough land to feed the whole world. Thus evidence of the last two centuries contradicts the Malthusian no4on of food supply increasing only arithme4cally. Rather than starva4on, food surpluses exist and agricultural produc4on increases. In 1992 European surpluses reached 26 million tonnes and there are indica4ons that this trend will con4nue, contrary to Malthusian theory.
Boserup's theory In 1965, Esther Boserup, a Danish economist, asserted that an increase in popula4on would s4mulate technologists to increase food produc4on (the op4mis4c view). Boserup suggested that any rise in popula4on will increase the demand for food and so act as an incen4ve to change agrarian technology and produce more food. We can sum up Boserup's theory by the sentence 'necessity is the mother of inven4on'.
Boserup's ideas were based on her research into various land use systems, ranging from extensive shining cul4va4on in the tropical rainforests to more intensive mul4ple cropping, as in South-‐East Asia. Her theory suggests that, as popula4on increases, agriculture moves into higher stages of intensity through innova4on and the introduc4on of new farming methods. The conclusion arising from Boserup's theory is that popula4on growth naturally leads to development. Limita*ons of Boserup's theory Like Malthus, Boserup's idea is based on the assump4on of a 'closed' community. In reality, except at a global scale, communi4es are not 'closed' because constant in-‐ and out-‐migra4on are common features. It has therefore been very difficult to test Boserup's ideas. This is because migra4on usually occurs in areas of over-‐popula4on to relieve the popula4on pressure, which, according to Boserup's theory, then leads to technological innova4on.
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Over-‐popula4on can lead to unsuitable farming prac4ces that may degrade the land. Consequently, some geographers have partly blamed popula4on pressure for deser4fica4on in the Sahel. From this it is clear that certain types of fragile environment cannot support excessive numbers of people. In such cases, popula4on pressure does not always lead to technological innova4on and development.
Applica*on of Malthus and Boserup There is evidence to suggest that the ideas of both Boserup and Malthus may be appropriate at different scales. On a global level the growing suffering and famine in some developing countries today may reinforce Malthusian ideas. On the other hand, at a na4onal scale, some governments have been mo4vated by increasing popula4on to develop their resources and so meet growing demands.
6. Summarise the Malthusian and Boserup models in the table below.
Study the graph to the right, showing popula4on and food supply in India. 7. As the popula4on of India increased what happens to the per capita food supply? Why?
8. Add a third line on the graph to show increase in food produc4on. Label each line.
9. Which of the above theories is represented by this data? Explain your reasoning.
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Malthus Boserup
ModelDiagram:
Main ideas:
Limita'ons
Applica'ons
10.Do you think that the concept of carrying capacity is applicable to the human popula4on? Use evidence from the textbook chapter and your reading in this study guide to jus4fy your response.
Global Population GrowthThe paGern of human growth is not uniform with most growth currently taking place in developing countries. Use the following data to construct popula4on growth curves for developed and developing regions of the world from 1800 un4l 2100 AD. Your graph should show both curves on the same grid and include appropriate labels and units of measurement for both x-‐ and y-‐axes.
11. Plot both the developing regions and the developed regions. (Units are billions of people: 109).
Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Table 2: Human Popula'ons in MEDC’s and LEDC’s, 1800 -‐ 2100 AD (in billions of people, 109)Date Developed Developing Date Developed Developing
1800 0.3 0.7 1980 1.1 3.3
1850 0.4 0.8 1990 1.2 4.1
1900 0.6 1.1 2000 1.3 5.0
1950 0.8 1.7 2025 1.4 7.2
1960 0.9 2.1 2050 1.4 8.0
1970 1.0 2.8 2100 1.4 8.0
12. The values for the next century are only es4mates. What will be the most important social factor that will determine human popula4on size? Why do you think so? Provide evidence and/or reasons to support your answer.
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Measures of Population Growth13. What are the four main factors that affect popula4on size of organisms?
Measures of popula4on change are crude birth rate, crude death rate, and natural increase rate.Crude birth rate is the number of births per thousand individuals in a popula4on per year.Crude death rate is the number of deaths per thousand individuals in a popula4on per year.
14. Crude birth and death rates are calculated by dividing the number of births or deaths by the popula4on size and mul4plying by 1000. Write these out as formulae:
Crude birth rate =
Crude death rate =
Natural increase rate is the rate of human growth expressed as a percentage change per year.
Natural increase rate* = (Crude birth rate -‐ crude death rate) / 10 (*migra4on is ignored)
15. Calculate the popula*on density, crude birth rate, crude death rate, and natural increase rate from the data provided in Table 3 below and complete the table.
Table 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by RegionTable 3: Changes in Global Human Popula'ons by Region
Region Pop’n106
Land Area 106 km2
Births106
Deaths106
Crude birth rate
Crude death rate
Natural increase rate
Pop’nDensity
World 6,000 131 121.0 55.8
Asia 3,500 31 88.2 29.4
India 1,000 3 29.0 10.0
Africa 730 29 30.7 10.0
Tanzania 30 0.9 1.3 0.4
Europe 730 22.7 8.5 8.2
Switzerland 7 0.04 0.09 0.07
N America 460 21.8 9.3 3.6
USA 270 9.6 4.3 2.4
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16. Popula*on density is defined as …
Fertility rate and predicted population growthPopula4on growth can be defined in terms of birth rate, doubling *me and fer*lity rate.
Fer*lity rate is the average number of children that the women in a par4cular popula4on have during their life4mes.
What will be the future world popula*on?Three billion women will decide the world popula4on in 2050. A fer4lity rate of 2.0 means that a couple replace themselves, and do not add to the popula4on. In this scenario the popula4on will increase from 6 billion now to 10.8 billion. If every second woman decides to have three rather than two children, a fer4lity rate of 2.5, the popula4on will rise to 27 billion by 2150. If, however, every second woman decides to have only one child instead of two, a fer4lity rate of 1.5, the world popula4on will sink to 3.6 billion. Total world fer4lity is now about 3.0, 1.7 in developed regions, and averaging 3.4 (but up to 6.0) in developing regions. Fer4lity rate is falling although popula4on size con4nues to increase. The UN has calculated es4mates for popula4on change based on fer4lity rates stabilising at 2.6 (high), 2.1 (medium/replacement level) and 1.6 (low).
Look at the popula4on curves for these three fer4lity rates un4l 2150 in the diagram below. Label the curves on the diagram with the fer4lity rates from the above paragraph.
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The status of womenWomen are the key to reducing the popula4on, but all too onen they conceive against their wishes.
Read the following ar4cle from the UNFPA.
17. Highlight or underline issues which maintain the low status of women in one colour and highlight or underline proposals which might lead to a lowering of fer4lity rate, in another colour.
The Declara*on and Programme of Ac*on of the World Summit for Social Development, held in Copenhagen in March 1995, called for equal educa4onal and work opportuni4es for women.
The Plavorm of Ac4on of the Fourth World Conference on Women held in Beijing in September 1995 also called for universal access to quality health services by 2015; equal land, credit and employment access to women; the establishment of effec4ve personal and poli4cal rights; and the educa4on of girls and young women as the key interven4on for the empowerment of women. In 1997, the United Na4ons High Commissioner for Human Rights reiterated that women's rights are fundamental human rights. Women's social status and access to educa4on, employment and health care are loosely linked to economic development. Women in many countries s4ll lack the right to own land, to inherit property or to have access to credit; girls are denied schooling; female workers rou4nely face job discrimina4on; and women’s sexual and reproduc4ve health needs are widely neglected.
Women onen face legal and ins4tu4onal barriers to economic ac4vity outside the home, including laws or customs that deny them the right to own land, inherit property, establish credit or move up in their field of work. Within the home, women with families usually have the primary responsibility for child care as well as carrying water; collec4ng fuel; growing, processing and cooking food, onen in addi4on to their paid employment.
Enhancement of their produc4ve roles is especially important for women whose status in society has been dependent solely on their reproduc4ve capabili4es. In the absence of other sources of status, a woman's ability to decide about a marriage partner or family size is limited. This is true for women in all countries.
Educa4on is a cri4cal ingredient in the empowerment process. Of the 960 million illiterate adults in the world, two thirds are female. The ICPD Programme of Ac4on calls for universal enrolment in primary school by the year 2015, a 4me line influenced by the magnitude of the task. Despite progress in expanding access to primary educa4on throughout the world, an es4mated 130 million children -‐ including 90 million girls -‐ are not enrolled in primary school.7 And while enrolment in primary and secondary school totals nearly 900 million children worldwide, there are about 85 million fewer girls than boys enrolled. For adult women, educa4onal aGainment is highest in developed countries where, except for Eastern and Southern Europe, women have an average of 10 years of educa4on or more. In Africa, women have an average of less than one year of formal educa4on.
The level of educa4on achieved by a woman is also strongly associated with both lower infant mortality and lower fer4lity. In poorer countries, where access to health care is onen limited, each addi4onal year of schooling is associated with a 5 to 10 per cent decline in child deaths. And the impact of a woman's educa4onal aGainment on family size is second only to that of access to family planning services. In combina4on, high levels of educa4on and access to family planning services translate into both lower infant mortality and lower fer4lity. In Sri Lanka and the Republic of Korea, where women have an average of more than six years of schooling, infant mortality rates are among the lowest in Asia and families have, on average, about two children.Gender discrimina4on onen begins long before a girl enters school. Deep-‐rooted tradi4ons of son preference can result in both passive and ac4ve neglect. A girl may be given less food than her brothers, be less likely to see a doctor when ill or be prevented from aGending school in order to help with household chores and child care. Access to new technologies is compounding the problem of son preference in some countries, where sex-‐selec4ve abor4on is a growing problem. Female genital mu4la4on is another gender-‐ based tradi4on with severe nega4ve consequences for the health of girls and women.
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Men's involvementThe ICPD Programme of Ac4on recognizes that men, in most socie4es, exercise preponderant power in nearly every sphere of life, ranging from personal decisions regarding the size of families to the policy and programme decisions taken at all levels of government. Achieving gender equality, equity and women’s empowerment will require the support of men.
Men also must play an ac4ve role in stopping the abuse of their daughters, wives, mothers and sisters by joining the effort to eradicate all forms of gender-‐based violence including domes4c violence, child pros4tu4on and rape.
Encouragement of joint decision-‐making in the family and of male support for their partners' choices related to reproduc4on is a vital component of an empowering and par4cipatory approach to reproduc4ve health.
Family planning programmes tradi4onally focused primarily on women via maternal and child health programmes. This approach generally neglected “male methods" of contracep4on -‐ condoms, vasectomy and withdrawal. It also placed responsibility for contracep4on decisions solely on women and impeded efforts to promote male responsibility. It may even have deterred contracep4ve use by women, par4cularly in cultures where men dominate reproduc4ve decision-‐making. (Where partners disagree on the number of children or the use of contracep4ves, the man's views will usually prevail.)
Studies show that men are more favourable to family planning than has been widely assumed, but these aytudes must be translated into support and coopera4on in decision-‐making. The development and use of male methods of contracep4on, which are safe, effec4ve, reversible and acceptable, would expand the op4ons for both men and women, aGract addi4onal users and improve reproduc4ve health. Male coopera4on and responsible sexual behaviour will be required to counter the AIDS pandemic and rising STD rates, since the male condom is the most widely available barrier to disease transmission. Men also need to be educated on the implica4ons of their sexual behaviour for their partners' health.
The following are among suggested op4ons that reproduc4ve health programmes may use to increase male involvement:
· Inform men about family planning and reproduc4ve health· Encourage joint decision-‐making by spouses· Provide contracep4ve choices· Design convenient, appealing services
Female Genital Mu*la*onFemale genital mu4la4on is a major public health issue: an es4mated 130 million women worldwide have under-‐gone some form of the procedure. It is prac4sed in one form or another in around 40 countries mostly in East and West Africa and parts of the Arabian Peninsula. As a result of migra4on from these areas, it is now also prac4sed in Europe and North America.
Each year it is es4mated, that about 2 million or more girls are at risk of mu4la4on. The procedure is usually per-‐ formed on young girls or adolescents and some4mes when a woman has just given birth. Because it is typically performed outside the medical system, without anaesthesia using unclean instruments, it can have grave health consequences. The commonest type of female genital mu4la4on is excision of the clitoris and the labia minora, accoun4ng for up to 80 per cent of all cases. The most extreme is infibula4on, which cons4tutes about 15 per cent of all procedures.
The ICPD was the first interna4onal conference to speak out plainly against it, calling on the interna4onal community to eliminate the prac4ce, which it stressed, violates basic human rights and cons4tutes a lifelong risk to women's health.
Visit www.unfpa.org for more informa4on.
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18. List four reasons why educa4ng women will reduce fer4lity/birth rate.
Population pyramidsPopula*on or age/sex pyramids (some4mes called popula4on profiles) show the distribu4on of individuals in a popula4on. Look at the popula4on pyramid below.
19. What kind of informa4on does a popula4on pyramid show?
20. Look at the bands indicated by the 3 arrows in the above pyramid. Describe the informa4on / trend indicated by the bars where each of the arrows is located.
Popula4on pyramids can indicate poli4cal and social changes too: China used the concept of op4mum popula4on to try to stabilise its popula4on at 1.2 billion by the year 2000 and reduce the popula4on to a government set level of 700 million by the end of the century.
21. Annotate the above diagram to show social and poli4cal changes. Jus4fy your response with reasons, examples, and/or other evidence.
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There are four basic popula*on pyramid shapes:
22. Complete the table below with the characteris4cs of each pyramid
Stage early expansive late expansive sta'onary contrac've
Birth rate
Death rate
Life expectancy
Popula'on growth
Analysing popula*on pyramids
Visit the website of the US Bureau of the Census, Centre of Interna4onal Research, UNDIESA, at www.census.gov and find the Interna4onal Database. The following popula4on pyramids, from the US Bureau of the Census, show projec4ons into the future for selected countries. hGp://www.census.gov/ipc/www/idbpyr.html Look at this site as it has dynamic pyramids changing over 4me.
23. For each pyramid below, iden4fy the stage. You might like to look up your own country, if not included, and do the same. Annotate pyramids with comments on the birth rate, fer4lity, death rate, life expectancy, gender differences and any special events.
Pyramid 1: Afghanistan
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Pyramid 2: Central African Republic
Pyramid 3: Italy
Pyramid 4: United Kingdom
Look up some more countries.24. What is happening in countries with high levels of AIDS?
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25. What is happening in MEDCs? China? India? Tanzania?
The Demographic Transition ModelDemographic transi4on is the paGern of decline in mortality and fer4lity (natality) of a country as a result of social and economic development. Demographic transi4on can be described as a four-‐stage popula4on model, which can be linked to the stages of the sigmoid growth curve (S-‐curve).
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The following diagram shows two demographic transi4ons. (BR = birth rate; DR = death rate)
26. For Country A, draw ver4cal lines on the graph to indicate the various phases of the transi4on model.
27. For Country B, use a different color pen or pencil to draw ver4cal lines on the graph to indicate the various phases of the transi4on model.
28. Provide evidence/data from the diagram to jus4fy your placement of the ver4cal lines showing the different stages of the demographic transi4on model.
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