System Interactions: Population Dynamics Lab InstructionsLab Objectives Before doing this lab you should understand:

System Interactions: Population Dynamics Lab InstructionsLab Objectives

Before doing this lab you should understand:

• Type I, Type II, and Type III survivorship curves
• how to create a semi-log graph

Lab Objectives

After doing this lab you should be able to:

• analyze mortality data and extract information to create survivorship curves
• compare and contrast male and female survivorship
• evaluate data for validity and suggest improvements to data-collection method

Materials

This is a hands-on lab experience in which you will be analyzing survivorship based on data provided by a cemetery.

You will need:

• a cemetery (or access to cemetery records)
• a calculator
• a pencil or pen
• paper

Background Information

Age-structure information about a population can be very helpful in analyzing its potential to persist and grow. By recording data on mortality rates for different age groups, it is possible to construct a survivorship curve for a population.

Procedure

Note: For the calculations in your lab, remember to set up the problem correctly, using units of measurement and showing all steps of the work. Showing your steps for solving the problem is a requirement in an Advanced Placement course, and it will be a part of your exam process. Numerical answers must include units of measurement to be considered correct.

1. Visit a nearby cemetery (be sure to call ahead to ask permission first) and collect data from at least 100 different gravestones (find 50 males and 50 females). You should note the gender and the age at death. Organize your data into a table like this (it is easiest to use tally marks):

AgeNumber of males who died at this ageNumber of females who died at this age0 to 5 years old  5 to 10 years old  10 to 15 years old, etc., by five-year intervals up to your oldest data point  

1. If a cemetery is not near your home or you prefer not to visit a cemetery, use the data from the Cazenovia cemetery and randomly choose 100 different individuals (50 males and 50 females) to complete the data table.
2. Analyze your data in terms of survivorship, like this:

AgeNumber of males who died at this ageNumber of males surviving at this age = 50 - number of males who died up to this agePercent surviving at this age = number of males surviving divided by 50, times 100        

Prepare a table like this for the females also.

1.  Create survivorship curves by plotting percent surviving (on the y-axis) versus age (x-axis). Create a graph for males and a graph for females, or, if possible, you can graph the male and female curves on the same graph (be sure to include a legend or key).

Reflection Questions:

1. Compare the male and female survivorship curves. Discuss any differences or similarities.
2. How valid are these survivorship curves? What factors might affect their accuracy?
3. What type of survivorship does your curve show? Is this what you expected?
4. Discuss ways to explore the information obtained in more depth.
5. How do you think the data would change if we focused on individuals born now and followed their survivorship patterns into the future?

Title: including your name, teacher's name, date, and name of lab

Objective(s): What was the main purpose of the lab or what question(s) are you trying to answer?

Introduction: What background information is necessary to know before completing this lab? What scientific concepts are being examined? Include any preliminary observations about the subject.

Hypothesis: Write a possible solution for the question or problem being investigated. The hypothesis statement should be testable and is often in an if-then-because format to illustrate the manipulated variable, the expected results, and the reason(s) for those expectations.

Procedure: What steps did you take to complete the lab? Clearly define the dependent and independent variables and the control group.

Data: This section should include data tables, graphs, and observations from the lab.

Conclusion: Generally the conclusion will include a summary of the lab results, an interpretation of the results, and an analysis of the original hypothesis. Any experimental errors should be reported and analyzed, and possible limitations of, or improvements to, the lab procedure should be identified. There may also be lab reflection questions that need to be answered here

P Biology Lab Write-Up Format Checklist

Title

Each of the following is included:

• your name
• teacher's name
• date
• name of lab

Objective(s)

Main purpose of the lab or what question(s) you are trying to answer are clearly listed

Introduction

• Necessary background information is included
• It is clear what scientific concepts are being examined
• Preliminary observations about the subject are listed

Variables

• Identify:
• the independent variable
• the dependent variable
• the constants and your control group
• It is clear how contants are control group are controlled in your procedure.

Hypothesis

• A possible solution for the question or problem being investigated is included
• The hypothesis statement is testable
• The hypothesis statement is written in an if-then-because format to illustrate:
• the manipulated variable,
• the expected results,
• and the reason(s) for those expectations.

Materials

Necessary materialst are listed. (Hint: It is best to compile this list after writing the procedure to make sure you include everything that is needed.)

Procedure

• List your procedure in numbered steps that are easy for a reader to follow.
• Make sure you are specific about how to set up the experiment,
• how to control each of the controlled variables, and
• how and when to make measurements and observations. 

Data Analysis

• A data table and a written description of how to process and analyze the data is included
• If it is necessary to plot data in a graph, it is clear how the graph should be set up and what should be analyzed.

Conclusion

The expected results that would support your hypothesis are included.