“Imagine You’re a Giraffe…” Barb Lamb
Activity adapted from Biology with TI-83 Plus
“Imagine You’re a Giraffe…”
Today we are going to pretend that we’re giraffes in the
wilds of
In this activity we will: Gather the heights of our “herd”
Use our TI-83 calculators to store and analyze data
Answer some questions about our data
Discuss our herd’s biological variation and “survival of the fittest” within our herd
Use the attached sheets for data collection and data analysis.
DATA COLLECTION
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Number in herd |
Height in inches |
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1 |
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2 |
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3 |
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4 |
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5 |
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6 |
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7 |
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8 |
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9 |
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10 |
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11 |
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12 |
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13 |
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14 |
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15 |
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16 |
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17 |
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18 |
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19 |
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20 |
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21 |
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22 |
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23 |
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24 |
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25 |
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26 |
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27 |
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28 |
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29 |
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PROCEDURE
After you have collected all the heights of our herd, take your TI-83 and:
1. Press STAT ENTER . Enter all of our herd’s data in L1.
2. Determine the average for all of the data by pressing 2ND [LIST] . Press > > to go to MATH, and then press 3: mean( Press 2ND [L1]
) and then press ENTER .
Answer question 1 on the Analysis page.
3. Determine the median of the herd’s data. Press 2ND [LIST] . Press > > to go to MATH and press 4: median( Press 2ND [L1] ) and then press ENTER .
Answer question 2 on the Analysis page.
4. Arrange the data in ascending order in L1. Press STAT 2: SortA( Press 2ND [L1] ) and then press ENTER .
Press STAT ENTER to go back to the list screen.
Answer question 3 on the Analysis page.
5. Represent your data graphically by producing a Boxplot. Press 2ND [STAT PLOT] . Press ENTER to select 1:Plot1. Set your TI-83 as shown below.
6. Press WINDOW . Enter these settings:
Xmin: slightly smaller than your smallest data value from #4 above Xmax: slightly larger than your largest data value from #4 above
Xscl: 0 Ymin: 0 Ymax: 0 Yscl: 0 Xres: 1
7. Press GRAPH.
Sketch your graph under question 4 on the Analysis page.
8. Press TRACE . The cursor will be at the median value for the data. Does this value match the value you recorded in #3 above? Press < and > to locate the five-number summary of your data.
Answer question 5 on the Analysis page.
ANALYSIS SHEET
1. Record the mean value _____________ In mathematics, what is meant by the mean?
2. Record the median value ______________ What is meant by the median of the data?
3. Record the smallest _____________ and the largest _______________ entries from L1. (Include units!)
4. Sketch your graph on the grid below:
5. Record the five-number summary of your date here, and then try to describe what these values mean.
MinX: ____________ What does this mean?
Q1: ______________ What does this mean?
Median: _____________ What does this mean?
Q3: ______________ What does this mean?
MaxX:____________ What does this mean?
6. How was variation shown in our herd?
7. What is meant by survival of the fittest?
8. Fitness does not always mean bigger, stronger, or faster. Think of some examples where being best fit may not mean being the biggest, strongest, or fastest.
9. Describe the relationship between fitness and natural selection.
10. What might happen to some of our herd whose heights are between MinX and Q1 ?
TEACHER NOTES
I plan to buy seamstress measuring tapes to use in class and place a few pieces of masking tape vertically on the walls for students mark off their height upon.
ANSWER KEY
1. The mean is the average of the data.
2. The median is the middle data point.
3. Answers will vary from class to class.
4. Graphs will vary.
5. Values will vary.
MinX is the smallest measurement.
Q1 means 25% of the data is less than or equal to this value.
Median means 50% of the data is less than or equal to this value.
Q3 means 75% of the data is less than or equal to this value.
MaxX is the largest measurement.
6. Heights vary among the herd.
7. Animals that are best suited to live in their environment are more likely to survive and reproduce.
8. Suggestions include camouflage (zebras), being smarter, adapting to climatic changes, etc.
9. The best fit to survive normally to survive (and also reproduce).
10. In the beginning of the activity, the height of the leaves was mentioned. Perhaps the smaller members of our herd might not be able to eat enough to survive.