Environmental Science - saugerties.k12.ny.us



Environmental ScienceName: _________________________________Demographics Computer LabGo to the website called “Habitable Planet: A Systems Approach to Environmental Science” #5 Human PopulationChoose Interactive LabsChoose Demographics LabOverview: Before civilization began to impact the human life cycle approximately 10,000 years ago, human beings had high birth and death rates. Today the world is in the midst of a demographic transition—a transition to low birth and death rates—as the ability to control both disease and reproduction increases. Along the way, between these extremes, populations go through an intermediate period of continued high birth rates, combined with low death rates, resulting in a population explosion. Because countries span a continuum along this transition, looking at the present demographics of countries around the world provides an opportunity to look forward or backwards in time: a post-transition country can get a glimpse of a situation resembling its own past from countries still in transition, and a transitional country may get a hint of its demographic future from countries that are further along the continuum.At the most basic level, the increase or decrease in population can be calculated by following the simple formula:GROWTH RATE = BIRTH RATE - DEATH RATEPlease note that this computer simulation does not take immigration or emigration into account, so we are looking at birth and death rates only. The birth or death rate is the total number of births or deaths per year. However, as you’ll see in the simulator, birth rates are normally expressed as number of births per woman (over her whole life) and death rates as a percentage of people who die in each age group.The overall population growth rate is only one of the differences among countries in different stages of the transition. The age-based population structure is also greatly affected. Note that the average fertility rate for women in the United States, for example, is 2.06, which is a replacement rate, i.e., enough children are born to replace their parents, with the additional small percentage representing those who die before reaching adulthood. The death rate likewise remains a constant percentage for each age group. The Simulator:Click to open the simulator in the upper right corner of the overview page. Look at the following control options on the simulator:Across the top: Lesson – drop down menu for three choicesCountry – drop down menu for seven choicesNext row:Simulator controlsSimulator parameters – drop down menus for avg. birth rate and avg. death rate where you can change the rate and shift the age distribution; pop. growth is given as a % for the year you finished the runGraphs: Population size, over time Population by age group, year in upper right cornerGo on to next page….Lesson 1: The Demographic TransitionIn this lesson, you will collect data on the growth of the populations in seven different countries from the year 2005 to the year 2050. Start with the U.S. Record the birth rate, death rate and % pop growth for the U.S. for 2005. Then click “Run” and allow the program to run until it stops on the year 2050. Then record the % pop growth for 2050 and notice how it has changed. Then sketch the graph called “population by age group” that is shown for 2050. (This is also called a population pyramid or age structure diagram.) Then collect data on all of the other countries in the drop down menu. Be sure to hit reset before every run.CountryBirthrate (2005)Death Rate (2005)% Pop. Growth 2005 (start of run)% Pop. Growth 2050 (end of run)Population by age group 2050 (end of run)USAChinaEgyptIndiaItalyMexicoNigeriaNumber the countries by growth rate from highest (earliest in the demographic transition) to lowest.Ranking of countries (list the seven in order)Name of Country1. Highest % pop. growth 2050Earliest in demographic transition Farthest in transition2. Next3. Next4. Next5. Next6. Next7. Lowest pop. growth 2050Answer the following questions.How do you suppose living conditions differ between the country furthest along in the demographic transition compared to the country earliest in the transition? How would living conditions in these two countries affect both birth and death rates?Think of three social factors that contribute to lower birth rates in the countries farther along. How might these social conditions be encouraged to emerge in less developed countries?How does the shape of the population pyramid differ from most developed to least developed country? Lesson 2, Population Momentum (IMPORTANT! Set lesson name at top of simulator to Population Momentum)In this lesson, we explore population momentum (the time lag between a change in birth/death rates and the slowing of population growth). Select Nigeria from the country pull down menu, run the simulator with the default settings to 2050, and record the results for pop growth in your Data Table. Then click “reset” to clear your run. Predict what will happen when the average age of childbearing women is increased by 5 years (fewer teenage pregnancies) and record your prediction as “increase”, “decrease” or “no change”. Now collect the data. Change the age of childbearing women by clicking on “avg birth rate,” selecting “Use rates from Nigeria” and then adding 5 years by clicking on “+5 years.” Click “ok.” Then run the simulator and record your results. Then predict the effect of subtracting 5 years and record on the data table. Again, click on “avg birth rate,” and again select “Use rates from Nigeria” (actually click on it to clear the previous change) and then subtract 5 years by clicking on “-5 years.” Click “ok” and run the simulator. Record your results.NigeriaDefault, run to 2050Predicted 2050 adding 5 yearsAfter running simulation to 2050 with +5yrsPredicted 2050 subtracting 5 yearsAfter running simulation to 2050 with -5yrsPop. GrowthHow does an increase in the average childbearing age group change the population? ________________How does a decrease in the average childbearing age group change the population? _________________Why do "first world" (= developed) countries tend to have older childbearing women than "third world" (= developing) countries? ____________________________________________________________________________________. ................
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