Lab Exercise #3: Life Tables

Lab Objectives

Construct life tables based on gender and mortality to determine correlations of the population in a given area
Introduction

My grandmother, Coby, when she was in her twenties in the 1930s.When our grandparents or great-grandparents were young, a common question asked when meeting someone for the first time was, “Where are you from?”. My grandmother (who was born in 1911) always asked someone new, “and where are your origins?”. As she suffered from dementia in the last few years of her life, she would ask my husband about twenty-five times a day what his origins were! Today, that is not usually one of the first questions we ask someone we are meeting for the first time. To some, it might even seem impolite and nosey. But where you “come from” can tell us a lot about whom and what we are. Certainly our southern accents can give us away, but aren’t they just about the most pleasant accent around! Our origins are something important to consider and even study because they can help scientists examine the correlations in populations and possible environmental trends that might be occurring due to these relationships.

My grandmother, Coby, when
she was in her twenties in
the 1930s.

Populations are always changing because alterations in the environment will occur across different areas and regions. Because it can be difficult to actually measure environmental changes, often changes in the population are measured instead because they can indicate environmental fluctuations. Plus measuring population changes can be easier for all involved. Some specific things that can be examined when measuring population changes include the number of births, deaths, immigration (moving into or entering another area/region/country), emigration (leaving your native place of origin), and the population in a certain area/region.

One method to help examine some of these fluctuations is to use a life table. A life table examines correlations (if any) between mortality and age of an individual within a specific environment. Life tables can help determine the interactions between human mortality (death) and sex (gender) of a given age in our region of Southwest Georgia or other surrounding areas. The goal for this lab is to make a life table that looks at life expectancy within our population. We will calculate mortality based on age and sex. Be thinking about what you expect the relationship between mortality and age and mortality and sex might be for our region.

We previously learned that population is measured based on numerical values for certain organisms within a given area. We looked at different ways to sample populations and obtain empirical data that provided us with the numbers we needed in order to make population calculations. For this lab, we will look for all the information we need to construct our life tables based on obituaries in the newspaper or online. Obituaries will tell us the sex and age (usually) of the deceased person. This will be all the information we will need for the construction of our life tables.

photo of newborn babyphoto of cemetary

Life tables can help determine correlations between environmental trends and populations.
Lab Supplies

This week your supplies will be very basic and hopefully easy for you to obtain. You will need to go online or to the library and access 28 straight days of obituaries in order. You will probably be most successful if you look at the obituaries of a larger city like Tallahassee, Atlanta, Albany or Dothan because the population is larger in these areas and will therefore have more deaths to use as data for your life table. Just make sure you use only one of these cities and record your information in sequence.

Procedures

Record the deaths from obituaries (either online or from the newspaper) from one of the cities listed above in the lab supplies for a four-week period (28 days).
For each individual, record their age and sex.
Finally, make an X-Y axis graph that illustrates the outcome of this information. On the graph, you should make age groups for every five years (0-4, 5-9, 10-14, 15-19, 20-24, 25-29, etc.). Count the total number of males and females that died for each age group. On the x-axis plot the age of death and on the y-axis plot the number of deaths for each age group. You can generate a line or bar graph to show your data. You will need to have two graphs, one for females and one for males. Use Excel or any other graphing tool of your choosing to make the graphs. However, these cannot be made by hand!
Lab Report

Describe the experimental design you carried out for constructing your life tables.
Provide your results by including your graphs.
In the introduction you were asked to think about what you thought the relationship between mortality and age and mortality and sex might be for our region. What did you think the relationship might be initially? Did the data support your expectations? Why or why not? If not, then what do you think the reason(s) might have been?
Were you surprised by any of the results? Why or why not?
Do you think your results represent our local region accurately? The national averages? Explain why you think what you think.