A Human Population Study
Steven L. Brown
Air Academy High School
Colorado Springs, Colorado
May 5, 1995
Type of Activity: Hands on Activity, Inquiry Lab, Group/Cooperative Learning
Target Audience: Life Science, Biology, Environmental Science
Background Information Required of Students:
In class, students will individually compile part of a collection of one year's obituary data for the region served by the local newspaper. This could be in the form of a stack of obituary clippings, or if the teacher is more motivated, a printed section of computer database results for the year. Each student will break down his section of the data to show how many males and females died in each 10-year age class. When finished, each student will report his findings on a class chart, and totals for each age class will be calculated.
Once the whole set of local data has been displayed on the board, each pair of students will work together to graph a Survivorship Curve (for males and females), and bar graphs of Deaths per Age Group and Mortality Rate. Upon completion of the graphs, students determine the local life expectancy for males and females, answer questions about what demographics are and how they are used, and try to come up with some explanations for the findings they made about the local population.
Preparation Time Needed
This could vary. The length of time chosen to sample the death rate of the local population could be as short as one month to more than one year. I chose to collect data for one year, but first attempted this activity with nine months worth of data. This could be done on a day-by-day basis, or if the local library has the newspaper saved on microfilm, the obituaries could be researched, printed, and cut out on one long Saturday. I started collecting the obituaries on January 1, presented the data that I had by September 1, and filled the other months, (and missing days gleaned from library records) to complete a data set that I will use for several years. Make no mistake, depending on the size of your community, this can be a big pile of data. For Colorado Springs, and the surrounding region (population about 400,000) this amounted to roughly 2,700 deaths (and, collected as an afterthought, about 4,500 births).
Class Time Needed
Once the activity is prepared in a laboratory format, a class could complete the graphs, answer questions, and engage in discussion in less than ninety minutes.
Notes for the Teacher
This activity involves using data on age of death gleaned from obituaries from the local newspaper to determine the numbers of deaths in each age class, and differences between male and female mean life expectancy. You will need to have totals of males and females that die in each ten-year age class, totals of how many died from all age classes, and calculations of mortality rate for each age class.
Once this data is ready and totals calculated the actual graphing and analysis goes pretty quickly. Rather than have the students spend the time randomly leafing through piles of clippings to derive totals, I simplified the student experience by arranging all of the data on a computer database, printing it out, and distributing sheets of organized data for students to count the males and females listed for each age class. Each student then only had to count about 100 entries and determine the numbers of each in each age class. However, this required about twelve hours of computer time on my part to load all of the data into the database and print it out.
I divided the population into ten-year age classes (i.e. 0-9 years, 10-19, etc., to 100+ years.) The first step would be to total how many died in each age class, separated into male and female categories. Then a total of how many of each died during the year. This could be totaled on the blackboard as students shared the results of the portion they counted, then the whole class' data totaled.
To determine Survivorship (for a line graph), total the number that died from age 0-9 for each sex, and subtract this value from the total that died of all ages. This product would show how many survived into the next age class. Continue to subtract the number that died from each class from those that still survive, until all deaths are accounted for, and 0 survive. The line graph that results from this will start high in the upper left of the graph, and descend to the lower right until survivorship equals 0.
The Mortality Rate is calculated for each age class, and each sex, by dividing the number of deaths by the total number of individuals in the study. This is displayed on a bar graph and should show a higher rate for the advanced ages.
This activity involves analysis of local obituary data to determine population demographics and mean life expectancies for males and females. Once the large amount of data has been graphed and analyzed a wide range of discussion opportunities are made available on topics from causes for the discrepancies between male and female age of death, to local population characteristics, health maintenance, student mortality causes, disease, and much more.
The purpose of this activity was to make students aware how much data was available, how the data could be processed and analyzed, practice in different types of graphing, and to generate discussions on population characteristics, their causes, and ramifications for the students.
The only materials needed to perform this activity are pencils, graph paper, a blackboard, and the obituary data (which could be individual clippings, pages from the newspaper or microfilm printer, or database printouts of sorted data).
This could be evaluated as a graded activity if the students are given follow-up questions to work on, or it could be ungraded and used as jump-off point for discussion and open-ended problems. The discussions often lend themselves to opening avenues that you may not have considered and create possibilities for further study, extension, or position papers displaying student opinions and feelings.
A natural extension that is also readily available in most newspapers involves not mortality, but natality, the number of births in the population for the same time frame. This gives a better picture of how the local population is changing, and can be compared with national trends.
This lesson was modified by Steven Brown from ideas shared in sessions of the NABT Convention in Denver, Colorado, November, 1992.