Intraspecies Variation Lab
You have probably heard the expression, “As alike as two peas in a pod.” Well how alike are those two
peas? Or two beans, or two humans for that matter? Two sheep may look alike to us but are easily
distinguished from one another by other sheep. The differences by which individuals of a single species
are distinguishable are known as variations. In this investigation, we will measure some variations in
individuals and look for any patterns which might exist in these variations. Later, we will use this
information to determine ways in which organisms might change over time.
PROCEDURE #1: Bean Length Measurement
1. Collect 30 lima beans and a metric ruler and graph paper.
2. Measure the longest length for each of the beans in millimeters and record your data below.
Bean Length
1.
6.
11.
16.
21.
26.
2.
7.
12.
17.
22.
27.
3.
8.
13.
18
23.
28.
4.
9.
14.
19.
24.
29.
5,
10.
15.
20.
25.
30.
3. Calculate the mean (average), median (middle value), and mode (most commonly occurring
value), and range of values for your bean length data. Record your results below.
Mean ___________
Median ________
Mode ________
Range ________
4. Organize your data by length interval using the chart below.
Bean Length
(mm)
13-14
15-16
17-18
19-20
21-22
23-24
25-26
27-28
# of Beans in
Interval
% of Total
Beans
Class Raw Data List
Class Average
PROCEDURE #2: Graphing Data
1. Create a spreadsheet in Google Sheets which includes columns for both your group measurements
and class average.
2. Create a line graph using both your group and class data. The x-axis should represent the bean
length intervals and and the y-axis should represent the number of beans within the interval.
3. Label your axes and create a legend to distinguish the two different data sets.
4. Insert a vertical line for both your group and class data. NOTE: You may need to use an external
program to add this line.
DISCUSSION:
Write a 3-paragraph essay (as a word document) with the following information:
1. Measurement -- this is a discussion of what you learned about “Lima Beans” from your
measurements and calculations (mean, median, range), what you learned about variation, and what
you learned about the shape of this sort of graph. This is worth more credit than the other two
paragraphs.
2. Link to Evolution -- In this paragraph, using evolution concepts you have learned in class and from
your reading, discuss how it can be an advantage to be a big or little seed? A disadvantage?
Remember, this is a developed paragraph and not a series of bullet points.
3. Conclusion -- Discuss what is best and what that depends on. Hint: changing conditions in nature
Insert your graphs into your document, print your discussion, and
attach to the data sheet.