2 Key Questions/Big Ideas Where is the world’s population distributed?Where has the world’s population increased?Why is population increasing at different rates in different countries?What tools do demographers use to study population?
3 Ecumene: the portion of the earth occupied by permanent human settlement. This terms come from a Greco-Roman term meaning the inhabited universe (or at least what they knew of it).Ecumenical 1 : worldwide or general in extent, infuence, or application 2 : of, relating to, or representing the whole of a body of churches 3 : leading toward agreement or cooperation among ChristiansLook at maps on p. 49 in your text that show how the ecumene has expanded since 5000 BCGeographia, Claudius Ptolemy (83 – 161 AD) Source: wikipedia
4 CartogramsA typical map shows countries in terms of their relative size and shape, with distortions, as we discussed, depending upon the projection used.It's possible, however, and sometimes very useful, to redraw the map with the sizes of countries made bigger or smaller in order to represent something of interest. Such maps are called cartograms and can be an effective and natural way of portraying geographic or social data.
6 Where is human population concentrated? Two thirds of world population lives in 4 regions:East AsiaSouth AsiaSoutheast AsiaEurope"Out of every 100 persons added to the population in the coming decade, 97 will live in developing countries." Hania Zlotnik, 2005
9 Arithmetic DensityThe total number of people divided by the total land areaKowloon City, Hong Kong 1989 (Picture Source: Wikipedial
10 Physiological Density The ratio of the number of people supported per unit area of arable land (land suitable for farming)
11 Agricultural DensityThe ratio of the number of farmers to the total amount of arable land
12 What do these densities tell us? A high density does not necessarily mean that a country has a high population count.If a country has a high physiological density then that means that the country has difficulty growing enough food.
13 What do these densities tell us? A higher agricultural density suggests that the available agricultural land is being used by more and may reach its output limit sooner than a nation that has a lower agricultural density.A country with a lower AgD may have more advanced farming techniques in place so that not as many people farm a large area of arable land using efficient machinery
14 Population Increase Natural Increase Fertility Mortality There are three factors that dictate the increase in a population:
15 Natural Increase Crude Birth Rate (CBR) Crude Death Rate (CDR) 20 births per 100 people alive=20Crude Death Rate (CDR)5 deaths for every 1000 people alive=5NIR=CBR-CDR(converted to percentages)Ex. 2%-.5% = 1.5% Natural Increase RateNatural Increase is given in a percentage. You calculate this percentage by subtracting the CDR from the CBR. In other words, the total number of people who die from the total number born in a given year. But these numbers are given not in percentages, but as a ratio: number born per thousand people. So, you have to convert these into a percentage: divide by 100 or move the decimal over two places.Try this one yourselves: CBR=25; CDR =20 What’s the NIR? 25-20=5 or .05%
16 Doubling timeHow many years does it take to double the world’s population?What factors does this figure depend on?total population to start withNIRThe total number of people in the world impacts the doubling time: the more total population, the more 1.5% is going to be! Consider a bank savings account that earns 5% interest. If I start with $100, first year earns $5, but second year earns $5.25, etc…
17 WhaotNotice that although the growth rate has declined….
18 …the world’s population is still increasing …the world’s population is still increasing. But it isn’t increasing as fast as it might be if the NIR had not declined.Q. What was the doubling time in 1960?
19 World Population Growth Over Time 1CEWhat do the bigger areas mean?What does it mean if an area is bigger in the later map? Smaller?Which areas have grown the most?Which have grown least, or shrunk in comparison?1900CE
20 FertilityTotal Fertility Rate (TFR) is the average number of children a woman will have in her childbearing years (15-49)How does TFR differ from CBR?Attempts to predict the future behavior (and, by extension, population), whereas CBR gives a picture of society at that momentWhat might TFR rates be useful for?What accounts for the huge variation in TFR’s? ( )
21 World Fertility Map (2005-2010) Can you figure out what the different colors mean? Blue: 0-1childen; 1-2, etc. up to purple, 7-8 children
23 Mortality How long do people live? What increases life expectancy for adults?Why do babies and children die?What is IMR?Why is it higher in some places than others?Why is it so high in the United States, relative to other MDCs?These are questions that demographers ask about when, why, and how people die. Which ones can you answer? What data or resources would you need to answer the rest?
24 Total Life ExpectancyThis map shows the total years of life expected to be lived by the current population, based on the life expectancy of children born in Life expectancy is calculated on the assumption that prevailing trends will continue. It is usually different for men and women. As you get older your whole life expectancy increases from that at your birth because you have survived so far.The longest life expectancy at birth is in Japan, at 81 years 6 months. The shortest life expectancy is in Zambia, at 32 years 8 months. The world average life expectancy is 67 years."The adult mortality rate [in Zambia] has increased in the last decade ... an adult has lost about 11 years of survival due to the AIDS problem ..." Buleti Nsemukila, 2003
25 Increased Life Expectancy What does this cartogram show us? Territory size shows the proportion of all extra years of life expected to be lived by the population there in 2002, compared with a similarly sized population in Decreases in life expectancy are not shown here.What contributes to increased life expectancy?
26 Increasing Life Expectancy "... adding person-years-of-life back into the life table is far easier to accomplish when it involves saving infants and children from dying of infectious diseases than ... saving people over the age of 70." S. Jay Olshansky, 2005
28 Total Births AttendedWhat does attended mean? Worldwide 62% of births are attended by skilled health personnel. This ranges from 6% in Ethiopia, to practically 100% birth attendance in Japan.The total number of births attended, shown on the map, depends partly on how many women there are and how many babies they have.Why does this make a difference?We’ll come back to this in Half the Sky later this year
30 Connection: Fertility and Mortality "...how many of us realize that, in much of the world, the act of giving life to a child is still the biggest killer of women of child-bearing age?" Liya Kibede, 2005
31 Population PyramidsWhat are they?What can we use them for?
32 Population Pyramids: Definition A display of a country’s population in groups of age and gender.Normally shows the percentage of the total population in 5-year age groups, the youngest group being 0-4 years of age at the base of the pyramid and the oldest group near the top.Shape of a pyramid is determined primarily by the CBR (Crude Birth Rate) over time in the community.
33 Some further definitions… Sex Ratio: number of males per hundred females in the population is the sex ratio.Dependency ratio: number of people who are too young or old to work, compared to those who are in their productive years.
34 How do we use Population Pyramids? The age structure of a population is extremely important in understanding similarities and differences among countries.Can help us see what stage of the demographic transition a given country is inDiscuss 4 stages, as well as terms: expanding, stationary, and contracting
36 Youth BulgeWhat are some of the challenges faced by countries who have a “youth bulge” in their population?
37 The Demographic Transition Stage 1: Low GrowthStage 2: High GrowthStage 3: Moderate GrowthStage 4: Low GrowthIf Stages 1 and 4 are both characterized by low growth? What is the difference? How does a society move from one to the next?Next few slides will address these questions.
38 Stage One: Low Growth Pre-modern Balance between birth and death rates (both high)Short life expectancyPopulation growth slow (.05% TIR)Doubling time 1-5,000 years (vs of late 20th century!)Pattern broken in Western Europe in late 18th centurySTAGE ONE is associated with pre Modern times, and is characterized by a balance between birth rates and death rates. This situation was true of all human populations up until the late 18th.C. when the balance was broken in western Europe.Note that, in this stage, birth and death rates are both very high (30-50 per thousand). Their approximate balance results in only very slow population growth. Over much of pre-history, at least since the "Agricultural Revolution" 10,000 years ago, population growth was extremely slow. Growth rates would have been less than 0.05%, resulting in long doubling times of the order of 1-5,000 yrs.
40 World Population since the Middle Ages Source:What caused the dip in late 14th century?Did it make any difference, in the long haul?
41 Stage Two: Rapid Growth Urbanizing/Industrializing Quickly rising populationDecline in death rateConsistent food source (Agricultural Revolution of 18th century)Improved health conditions (water supply, sewage, personal hygiene)Birth rate remains highSTAGE TWO sees a rise in population caused by a decline in the death rate while the birth rate remains high, or perhaps even rises slightly. The decline in the death rate in Europe began in the late 18th.C. in northwestern Europe and spread over the next 100 years to the south end east. Data from Sweden clearly show this stage (and two other stages following it):
42 Demographic Change in Sweden (chart source)Look what happens to the CDR around Yet CBR stays high for another 100 years. Not until the CBR begins to drop, too,does Sweden really enter Stage 3: Moderate Growth
43 Stage Three: Moderate Growth Mature Industrial Birth rate decliningLow death rate; longer life expectancyImmigration from less developed countries may account for much of the population growth in MDCs that are in Stage IIIChina, South Korea, and Cuba are quickly approaching Stage IIIU.S. is in Stage IIIImmigration from less developed countries now accounts for much of the population growth in developed countries that are in Stage III of the transition. Countries like China, South Korea, Singapore, and Cuba are rapidly approaching Stage III.
44 Chile: Stage 3One of few countries outside of Namerica and Europe that has reached Stage 3.
45 Stage Four: Low Growth Post-Industrial Low death rateLow birth rateHigher dependency ratioLonger life expectancyGermany, Denmark are examples
46 The Census Picture Source: blogs.villagevoice.com Who conducts it?When?Why is it important?Why is it inaccurate and what are the implications of these inaccuracies?Picture Source: blogs.villagevoice.comPicture Source: simple.wikipedia.org
47 Malthus’ Principle of Population Political economist in EnglandConcerned by decline of living conditions caused by three things:overproduction of the young (fertility)Inability of resources to keep up with rising populationIrresponsibility of lower classesMalthus was a political economist who was concerned about, what he saw as, the decline of living conditions in nineteenth century England. He blamed this decline on three elements: The overproduction of young; the inability of resources to keep up with the rising human population; and the irresponsibility of the lower classes. To combat this, Malthus suggested the family size of the lower class ought to be regulated such that poor families do not produce more children than they can support. Does this sound familiar? China has implemented a policy of one child per family (though this applies to all families, not just those of the lower class).Source: UC Berkeley Museum of Paleontology;
48 Malthus’ theory of overpopulation Poverty and famine are natural outcomes of population growth and insufficient food supplyIf left unchecked (i.e. family size regulated), overpopulation will exhaust resources and famine will take over the worldHis argument was not popular with the social reformers of his time, who believed with proper social structures, all social ills can be remedied.
49 Epidemiology Epidemic Pandemic Epidemiology is the study of human health in populations, rather than in individuals. It studies the causes of illness, how a particular disease is spread, and disease control. Epidemiology is, literally, the study of epidemics.Epidemics and pandemics refer to the spread of infectious diseases among a population. The difference between an epidemic and a pandemic is two-fold. First a pandemic is normally used to indicate a far higher number of people affected than an epidemic, and a pandemic refers to a much larger region affected. In the most extreme case, the global population is affected by a pandemic.An epidemic is defined by an illness or health-related issue that is showing up in more cases than would be normally expected. However, in the case of a pandemic, even more of the population is affected than in an epidemic.Source for this info: wisegeek.com