| Using the Scientific Method |  |
Introduction:
Humans are classified as a separate species because of all the special characteristics that they possess. These characteristics are controlled by strands of DNA located deep inside their cells. This DNA contains the code for every protein that an organism has the ability to produce. These proteins combine with other chemicals, within the body, to produce the cells, tissues, organs, organ systems, and finally the organism itself. The appearance of these organs, such as the shape of ones nose, length of the fingers, or the color of the eyes is called the phenotype.
Even though humans contain hands with five fingers, two ears, or one nose, there are subtle differences that separate these organs from another. There are subtle differences in a person’s genes that allows for these different phenotypes. In this lab, we are going to observe some of these differences in phenotype. All human hands look pretty much alike, but there are genes on your chromosomes that code for the characteristics making up your hand. We are going to examine two of these characteristics (hand width and hand length) and try to determine why these phenotypic differences occurred.
Materials:
- metric ruler (see end of lab)
- pencil
- calculator
Procedures:
Day 1
- Choose a partner and have them measure the length of your right hand in centimeters. (Measure from the tip of your middle finger to the beginning of your wrist as shown in figure 1.) Record your measurements in Table 1.
- Now measure and record the length in centimeters of your partners hand.
- Have your partner measure the width of your right hand, straight across the palm, and record the data in Table 1. (see figure 1.)
- Now measure & record the width of your partner’s hand.
Figure 1.
Table 1
| Group Data on Right Hand Width and Length | ||
| Student Name | Length of Hand (cm) | Width of Palm (cm) |
- After the entire class has completed Table 1, record your group data on the Class Data Table at the front of the room
- Record the Class Data Table information on your lab sheet’s Table 2.
Table 2
Class Data on Right hand Width and Length (cm) |
|||
Class Period: |
|||
| Student | Gender (M / F) |
Hand Length (cm) | Hand Width (cm) |
| 1. | M / F | ||
| 2. | M / F | ||
| 3. | M / F | ||
| 4. | M / F | ||
| 5. | M / F | ||
| 6. | M / F | ||
| 7. | M / F | ||
| 8. | M / F | ||
| 9. | M / F | ||
| 10. | M / F | ||
| 11. | M / F | ||
| 12. | M / F | ||
| 13. | M / F | ||
| 14. | M / F | ||
| 15. | M / F | ||
| 16. | M / F | ||
| 17. | M / F | ||
| 18. | M / F | ||
| 19. | M / F | ||
| 20. | M / F | ||
| 21. | M / F | ||
| 22. | M / F | ||
| 23. | M / F | ||
| 24. | M / F | ||
Click for Class Data Table
Day 2
- In order to form a more accurate conclusion, the collection of additional data is necessary. Using the Class
. The teacher has the option to include the data from all the classes running this experiment. Below find tables that will allow the tabulation of several classes of data.
Table 3: All Classes Hand Length
| Measurement of Hand length in cm. | # of Males | # of Females | Total # ( Male + Female ) |
| 1.—————— | ——————– | ——————- | —————— |
| 2.—————— | ——————- | ——————- | ——————- |
| 3.—————— | ——————- | ——————- | ——————- |
| 4.—————— | ——————- | ——————- | ——————- |
| 5.—————— | ——————- | ——————- | ——————- |
| 6.—————— | ——————- | ——————- | ——————- |
| 7.—————— | ——————- | ——————- | ——————- |
| 8.—————— | ——————- | ——————- | ——————- |
| 9.—————— | ——————- | ——————- | ——————- |
Table 4: All Classes Hand Width
| Measurement of Hand width in cm. | # of Males | # of Females | Total # ( Male + Female ) |
| 1.—————— | ——————– | ——————- | —————— |
| 2.—————— | ——————- | ——————- | ——————- |
| 3,—————- | ——————- | ——————- | ——————- |
| 4.—————— | ——————- | ——————- | ——————- |
| 5.—————— | ——————- | ——————- | ——————- |
| 6.—————— | ——————- | ——————- | ——————- |
| 7.—————— | ——————- | ——————- | ——————- |
| 8.—————— | ——————- | ——————- | ——————- |
| 9.—————— | ——————- | ——————- | ——————- |
Line Graph the data from Tables 3 and 4. and then answer the questions that follow. Use the measurements of the width and length as your independent variable and the number of times that measurement appeared as your dependent variable.
Graph Tile: ___________________________________________________________
Analysis:
1. Examine the above graph. What is the shape of the line for hand length? _____________
________________________________________________________________________
2. What is the most abundant measurement for hand length? __________________.
3. What is (are) the least abundant measurement(s)? _________________________.
4. If we are to assign letters to represent the various lengths, what value(s) would we assign to the dominant genotype (HH)? ________________; the recessive genotype (hh)? ___________, and he heterozygous genotype (Hh)? _________________.
5. What would be the phenotypic name for the ( HH ) genotype? ___________________.
6. What would be the phenotypic name for the ( Hh ) genotype? ___________________.
7. What would be the phenotypic name for the ( hh ) genotype? ____________________.
8. Examine the above graph. What is the shape of the line for hand width ? ____________
________________________________________________________________________
9. What is the most abundant measurement for hand width? __________________.
10. What is (are) the least abundant measurement(s)? _________________________.
11. If we are to assign letters to represent the various lengths, what value(s) would we assign to the dominant genotype (WW)? ________________; the recessive genotype (ww)? ___________, and he heterozygous genotype (Ww)? _________________.
12. What would be the phenotypic name for the ( WW ) genotype? __________________.
13. What would be the phenotypic name for the ( Ww ) genotype? ___________________.
14. What would be the phenotypic name for the ( ww ) genotype? ___________________.
15. Are there any similarities in the graph of the above two characteristics? ____________.
16. If so, what are they? ____________________________________________________
17. Are there any differences in the graph of the above two characteristics? ____________.
18. If so, what are they? ____________________________________________________
19. Is there a difference in the length and width of the male and female hand? ___________.
20. Does the gender of a person have an effect on the phenotype of a trait? _____________.
Explain _________________________________________________________________
_______________________________________________________________________
________________________________________________________________________
Cut and use:
________________________________________________________________________
