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The Demographic Transition 1. Low growth– 3. Moderate growth 2. High growth– 4. Low growth Population pyramids Age distribution Sex ratio Countries in different stages of demographic transition Demographic transition and world population growth
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Demographic transition – The changes in natural increase caused by shifts in birth and death rates in a given area of the Earth.
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Fig. 2-13: The demographic transition consists of four stages, which move from high birth and death rates, to declines first in death rates then in birth rates, and finally to a stage of low birth and death rates. Population growth is most rapid in the second stage.
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Low Growth High Growth Moderate Growth Low Growth 1) Most of our time on Earth 2) High birth and high death rates NIR is around 0 with population of world around ½ million 3) Food is unpredictable 4) Despite beginning of human settlement, war and disease balance out high birth rates (families depend on children for farming) Present Day: No countries here 1) Industrial Revolution in England and North America (1750-1800) 2) High Birth and decreasing death rates 3) 10x faster growth 4) Stabilization of food supply, improvement of sanitation techniques, and creation of wealth through technology and invention Present day: 1950 – most of Africa, Asia, Lat. Am. 1) CBR drops, but still is higher than CDR; - CDR continues to decline, but at a slower rate 2) CBR declines due to changes in customs, people choose to have fewer children because of changes in female roles, jobs in service/urban areas Present Day: Beginning of 20 th century Europe and North America, most of Asia and Latin America by end of 20 th century 1)CBR declines to the point where it equal CDR 2)NIR approaches zero (Zero Population Growth or ZPG) 3)TFR falls beneath the 2.1 replacement rate 4)Women enter the workforce, more access to birth control methods, more leisure/entertainment time Present Day: Much of Europe, Russia as example Stage 5? High CDR and irreversible population decline
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1) Most of our time on Earth 2) High birth and high death rates NIR is around 0 with population of world around ½ million 3) Food is unpredictable 4) Despite beginning of human settlement, war and disease balance out high birth rates (families depend on children for farming) Present Day: No countries here Back
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1) Industrial Revolution in England and North America (1750-1800) 2) High Birth and decreasing death rates 3) 10x faster growth 4) Stabilization of food supply, improvement of sanitation techniques, and creation of wealth through technology and invention Present day: 1950 – most of Africa, Asia, Lat. Am. Back
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1) CBR drops, but still is higher than CDR; - CDR continues to decline, but at a slower rate 2) CBR declines due to changes in customs, people choose to have fewer children because of changes in female roles, jobs in service/urban areas Present Day: Beginning of 20 th century Europe and North America, most of Asia and Latin America by end of 20 th century Back
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1)CBR declines to the point where it equal CDR 2)NIR approaches zero (Zero Population Growth or ZPG) 3)TFR falls beneath the 2.1 replacement rate 4)Women enter the workforce, more access to birth control methods, more leisure/entertainment time Present Day: Much of Europe, Russia as example Back
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Low growth until 1750 – bubonic plague causes a decline as does famine, bad harvests High growth 1750—1880 industrial revolution food supply is more stable, money though industrial employment Moderate growth 1880-1970s – Low growth now now has 50 million vs 6 mil in 1 st stage Fig. 2-14: England was one of the first countries to experience rapid population growth in the mid-eighteenth century, when it entered stage 2 of the demographic transition.
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Stage of demo transition gives it a specific shape Mostly determined by the CBR Dependency ratio-the number of people who are too young or too old to work compared to the number of people in their productive years – usually divided into 3 groups 0-14, 15-64, 65 older Stage 2 1 worker for every dependent, stage 4 2 workers for every 1 dependent Elderly percentage increases as you move through the stages Stage 4 countries have higher cdrs because population is older
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1/3rd of the world population is under 15 Sex ratio – number of males /100 females; more males than females are born, but men die earlier in Europe/NA 95/100 rest of the world 102/100, in US males under 15 exceed females 105/100 – women start outnumbering men around age 40 by 65 women are 58% In LDCs high maternal death rates cause the figure to be skewed
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Fig. 2-16: Population pyramids can vary greatly with different fertility rates (Laredo vs. Honolulu), or among military bases (Unalaska), college towns (Lawrence), and retirement communities (Naples).
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12 small islands off coast of west africa Colony of portugal until 1975 Moved from 1-2 in 1950 Many famines Pop has tripled, natural increase is 3% Fig. 2-17: Cape Verde, which entered stage 2 of the demographic transition in about 1950, is experiencing rapid population growth. Its population history reflects the impacts of famines and out-migration.
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Moved from rural to urban Many still prefer large families Was still stage 1 as of 1900 Most pop increase is from immigration 1930s move to stage 2 – medical tech; stage 3 since 1960s –vigourous government family planning, high unemployment rates; govt reversed its policy Fig. 2-18: Chile entered stage 2 of the demographic transition in the 1930s, and it entered stage 3 in the 1960s.
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Stage 4 Zpg Increasing # of elderly raises cdr Fig. 2-19: Denmark has been in stage 4 of the demographic transition since the 1970s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children.
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Information for pop pyramids is obtained through census taking Most countries are in 2 and 3 stage – rapid growth/moderate growth 2 things impacting the model today – tech innovation has diffused throughout the world which drops cdr, cbr continues to increase bc social customs have not changed 19 th c change in cdr due to industiral revolution; drop in cdr in other places due to diffusion of this tech
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