In Unit II, you learned that the characteristics of a population at a given time can be represented graphically using birth and death rate data, among many other parameters. In Part I of this activity, you will work with a simple data set to create a human survivorship curve and answer questions about the results and the data itself. In Part II, you will work with interactive age structure diagrams (see unit lesson part II, Slide 22, Figure 3 for an example) in an online simulator to analyze population growth trends for both China and the United States. Part I: Constructing a Survivorship Curve
Survivorship curves are created by estimating the age of an organism at the time of its death and the number of deaths within each age bracket inside of a given population of organisms. Once constructed, survivorship curves create a general picture of the life history of that organism. The two biggest influences on the shape of a survivorship curve are predation and disease. There are three general survivorship curve types: Type III: Indicates a high mortality rate of the young.
Type II: Indicates a constant mortality rate throughout the life span of the organism.
Type I: Reflects a low mortality rate among the young with individuals dying at the end of their life span. Activity
In the United States, the current average life span of a human female is about 83 years of age, and the average life span of a human male is about 77 years. For this activity, we will assume that the average life span is 80 years of age. For Table 2a below, age brackets in five-year increments were created. Age data was collected randomly from 100 newspaper obituaries from around the United States and entered into the age bracket Table 2a. Using this data, you will complete the survivorship information in Table 2b and construct a survivorship curve using an Excel spreadsheet table. You will create a graph from the data and import it later in this assignment.
Completing the Survivorship Data Table Procedure (Table 2b) (10 points) 1. Enter the data from “Number of Deaths” column for each age bracket in Table 2a into the “Number of Deaths” column in Table 2b.
2. To calculate the data for the “Number of Survivors” column in Table 2b, start by subtracting the number of deaths in age bracket 1-5 from the number of survivors in age bracket 0. This number will be 100, of course. Continue subtracting the number of deaths in each age bracket from the number of survivors in the preceding age bracket. (Hint: The number of survivors will be 100 until you get to age bracket 21-25, where you will subtract 2, making the number for that bracket 98. Continue the process through the last age bracket. The number of survivors in age bracket 91-100 should be 0). 3. Create a line graph using Microsoft Excel and the data from Table 2b. The X-axis should reflect the Percent Life Span (%) and the Y-axis data should reflect the number of survivors data that you calculated.
Table 2a