WKU Anth 450 Lab 1

Anth 450 Modern Human Biological Variation
Dr. Darlene Applegate
Fall 2007
Lab 1: Anthropometry and Dermatoglyphics

INTRODUCTION

One approach to measuring modern human biological variation is anthropometry, which is the "physical measurement of human body form" (Molnar 2002:8). Historically, anthropometry focused on metric cranial measurements (eye width, nose length, head circumference, cranial capacity) because it was believed the skull changed little over time and because the brain was associated with human intelligence (see Molnar 2002:8-12; Gould 1996:20). But anthropometry includes measurement of other metric body traits, such as arm length, skin fold thicknesses, and standing height (France 2004).

Besides measuring different aspects of the human body, anthropometry also involves the statistical manipulation of the resulting data. Such calculations are done to detect patterns in the data that may be explained by genetic and/or environmental factors.

Dermatoglyphics refers to "[t]he study of patterns of dermal ridges present on the fingers and palms of the hands and toes and soles of the feet of humans and other primates" (France 2004:205). It includes the study of metric and nonmetric characteristics of dermal ridges. An example of a metric measurement of dermal ridges is ridge count. Dermal ridge pattern is an example of a nonmetric characteristic of dermal ridges.

OBJECTIVES

Upon successful completion of this lab, students will

learn to measure common anthropometric traits.

practice using anthropometric measuring devices.

practice statistically manipulating anthropometric data.

know how to produce a frequency distribution.

assess human variation between males and females.

learn to identify basic patterns of dermal ridges.

READINGS

Read Chapter 11 in France (2004). We won't be doing any exercises related to osteometry (pages 193-204) since this topic is covered in Anth 300 Forensic Anthropology, but it is important that you read this section as it is relevant to understanding the Gould text.

Be sure to bring the France reading and this lab overview to lab.

USING ANTHROPOMETRIC MEASURING DEVICES

We will be using several anthropometric measuring devices to complete this lab: sliding caliper (digital), sliding caliper (non-digital), spreading caliper, folding rule and fiberglass tape. We will also be using hand lenses for magnification of fingerprints. Carefully follow the directions for using these devices to insure that the instruments are not damaged. Pieces of anthropometric equipment are expensive because of the precision with which they are manufactured; special care in using the equipment must be exercised at all times.

The sliding caliper is used to make linear measurements. We are using digital sliding calipers that run on batteries and non-digital (manual) calipers. The level of accuracy for the calipers is 0.01 cm and your measurements must be recorded to that level of accuracy. The spreading caliper is used to make linear measurements around the protrusions on the body. The level of accuracy is 0.1 cm but you should estimate to 0.01 cm. The folding rule is used to make linear measurements larger than those that can be measured by a sliding caliper. The level of accuracy is 0.1 cm. The fiberglass tape is used to make nonlinear measurements. The level of accuracy is 0.1 cm. The hand lens is used to examine fingerprint patterns under low magnification of 10x.

MANUAL SLIDING CALIPER

1. Depress and hold the release button on the bottom part of the caliper.

2. Slide the right half of the caliper to the right to open it up. Open it beyond the size of the body part being measured.

3. Place the body part between the two lower pinchers.

4. Gently slide the right half of the caliper back to the left to close the lower pinchers.

5. Read the measurement from the top line of measures. (Metric along the top, English along the bottom.) The numbers correspond to centimeters. The tick lines between the numbers correspond to millimeters. Select the closest millimeter reading without going over. The small scale is for tenths of a millimeter; find the number along this scale that best lines up with a number of the main centimeters scale. Your answer should read, for example, 2.35 cm.

6. Depress and hold the release button and slide the right half of the caliper to the right again to open it up.

7. Remove the caliper.

8. Close the caliper.

DIGITAL SLIDING CALIPER

1. Close the caliper completely.

2. Press the ON/ZERO button to turn on the caliper.

3. Make sure the caliper is set on metric (millimeters) instead of English (inches). Press the MM/IN button to change from English to metric if needed.

4. Press the ON/ZERO again to reset the caliper to zero.

5. Slide the right half of the caliper to the right to open it up. Open it beyond the size of the body part being measured.

6. Gently slide the right half of the caliper back to the left to close it against the edge of the body part.

7. Read the measurement, which is expressed as 000.0 mm.

8. Slide the right half of the caliper to the right again to open it up.

9. Remove the caliper.

10. Close the caliper.

11. Press the OFF button when you are done measuring.

12. Divide the measurement by 10 to convert from mm to cm.

SPREADING CALIPER

1. Place one end of the spreading caliper on the first body landmark, supporting the end of the caliper with your finger if needed.

2. Place the other end of the spreading caliper on the second body landmark, supporting the end of the caliper with your finger if needed.

3. Read the measurement. The numbers on the scale are centimeters, and the tick lines between the numbers are millimeters. You'll have to estimate the measurement of tenths of a centimeter. For example, 35.73 cm might be the reading.

4. Open the spreading caliper away from the body landmarks.

5. Remove the spreading caliper.

6. Close the spreading caliper.

FOLDING RULE

1. Carefully unfold the rule. Do this slowly or you risk snapping the wood.

2. Place one end of the rule on one body landmark.

3. Read the measurement, which is expressed as 0.0 cm, at the other body landmark.

4. Slowly and carefully refold the rule when finished.

FIBERGLASS TAPE

1. Carefully draw out a portion of the tape.

2. Place the end of the tape on one body landmark.

3. Place the tape on the other body landmark.

4. Read the measurement, which is expressed as 0.0 cm.

5. Slowly rewind the tape (in the correct direction) when finished.

HAND LENS

1. Don't scratch the surface of the lens while using it.

2. Avoid touching the lens as this leaves fingerprints.

LAB SESSION 1:
ANTHROPOMETRY, FREQUENCY DISTRIBUTIONS, DESCRIPTIVE STATISTICS, AND CORRELATION

Our class members represent a sample of humans. During the first lab session we will be taking anthropometric measurements on our sample, assessing interobserver error in anthropometry, sharing data, graphing a frequency distribution for the sample, and calculating descriptive statistics to numerically describe the sample.

Review pages 185-190 in France (2004).

Step 1 will be completed in lab using the answer sheet provided in class.

Step 2 will be completed on your own using the answer sheet provided in class.

STEP 1: DATA COLLECTION

1. Using the appropriate measuring device, measure your partner's metric traits listed in the Measurement Record on page 191 in France.

Record the data clearly and legibly on the answer sheet provided.

We are doing all traits except the last two skinfold traits, for a total of 13 traits.

For middle finger length, arm length, and upper arm circumference, measure both the right and left finger/arm.

Note that all these measurements must be expressed in cm and must be accurate to the level given for the specific measuring instrument used (as explained previously). Don't simply add a "0" at the end of your measurement in order to achieve the appropriate level of accuracy.

Refer to France's directions (pages 189-190) for measuring these traits.

2. When everyone is finished with the measurements, we will tally everyone's data on the answer sheet.

Everyone must record the data accurately as it will be used to answer other questions in this lab assignment.

3. All students will measure the instructor's middle finger length on both hands.

Record your measurements on the answer sheet.

4. When everyone is finished with the measurements, we will tally the instructor's finger data on the answer sheet.

Everyone must record the data accurately as it will be used to answer other questions in this lab assignment.

STEP 2: STATISTICAL CALCULATIONS AND DATA INTERPRETATION

1. Calculate averages/means for each of the 13 traits you recorded for the class members.

For each trait, calculate three averages: males only, females only, and total sample. So you'll have a total of 39 average calculations.

Record all averages neatly on the answer sheet, along with the sample sizes for males, females, and the total group.

The formula for calculating averages/means is on page 186 of the France workbook, or use Excel on your computer.

Be sure to round the averages to the nearest hundredth. You do not need units for these data, as the units are included already on the answer sheet.

2. What differences do you observe between males and females in the average measurements for the traits?

3. What possible explanations are there for differences between males and females in the average measurements for the traits?

4. Calculate standard deviations for each of the 13 traits you recorded for the class members.

For each trait, calculate three standard deviations: males only, females only, and total sample. So you'll have a total of 39 standard deviation calculations.

Record all standard deviations neatly on the answer sheet, along with the sample sizes for males, females, and the total group.

The formula for calculating standard deviations is on page 186 of the France workbook, but please note that there is an error in the formula. We will discuss this in class. Or, use Excel on your computer to do the calculations.

Be sure to round to the nearest hundredth. You do not need units for these data, as the units are included already on the answer sheet.

5. What differences do you observe between males and females in the standard deviations for the traits?

6. What possible explanations are there for differences between males and females in the standard deviations for the traits?

7. Using one piece of graph paper provided, plot a frequency distribution of standing height for the entire sample.

We're using seven intervals to plot standing height: 130.0 to 139.9 cm, 140.0 to 149.9 cm, 150.0 to 159.9 cm, 160.0 to 169.9 cm, 170.0 to 179.9 cm, 180.0 to 189.9 cm, and 190.0 to 199.9 cm. These intervals correspond to the x-axis of the chart.

Count up how many people fall into each of these intervals. These numbers are frequencies, which correspond to the y-axis of the chart. You will need to add an appropriate scale to the y-axis.

For each interval with a frequency of at least one person, draw a bar as high as that frequency for that interval. This will result in a bar graph showing the frequency distribution for your sample.

Then make a small dot at the midpoint at the top of the interval bar and the corresponding frequency and connect the dots; note that if there are no individuals for a particular interval, your dot should be placed at 0 on the chart. This is a line graph showing the frequency distribution for your sample.

Add a title to the frequency distribution.

Click here for an example of a frequency distribution.

8. In a few sentences, describe the frequency distribution of standing height for the entire sample.

Is the frequency distribution unimodal or bimodal or trimodal?

Does the mode (the most frequently occurring height) correspond with the average/mean?

Are the data normally distributed or skewed?

Is the range of heights broad (corresponding to a large standard deviation) or narrow (corresponding to a small standard deviation)?

9. Using another piece of graph paper provided, plot frequency distributions of standing height for males and females on the same graph.

Add an appropriate scale to the y-axis.

Use two different colors for graphing the data for each sex.

Fill in the key for the graph, indicating which color is the male data and which color is the female data.

Add a title to the frequency distribution.

10. In a few sentences, describe the frequency distributions of standing height for the male and female samples.

Are the frequency distributions unimodal or bimodal or trimodal?

Do the modes correspond with the averages/means for the two data sets?

Are the data sets for each group normally distributed or skewed?

Is the range of heights for each group broad or narrow?

11. Calculate the ranges, averages, and standard deviations for the data on the instructor's left and right middle finger lengths.

You should have a range, an average, and a standard deviation for each hand.

Use all student data (the entire sample) in your calculations.

Round your answers to hundredths place.

12. Evaluate inter-observer error in the instructor's finger data.

Which set of data (right or left hand) has the most inter-observer error? How did you determine this?

Why is there inter-observer error in this measurement?

13. Answer question number 2 on page 191, assuming that the longer finger is on the side/hand used primarily by the subject.

In calculating differences, substract Left from Right using the formula (difference = right - left).

Positive differences mean right is larger than left, while negative differences mean left is larger than right.

14. Assuming the data are not faulty, answer question 7 on page 192.

Among other factors, consider the type of variation (phylogenetic, geographic, ontogenetic, sexual dimorphism, idiosyncratic) and the four forces of evolution in composing your answer.

15. Answer this modified version of question 7: If you had a large sample of one age for maximum height, and you found that the range of measurements was SMALL, what would you expect some of the explanations for this variability to be?

Among other factors, consider the type of variation (phylogenetic, geographic, ontogenetic, sexual dimorphism, idiosyncratic) and the four forces of evolution in composing your answer.

Your answer to question #15 should be different from your answer to the previous question #14.

16. Answer question number 8 on page 192, then do the actual correlation calculations to see if your prediction is correct and interpret the results.

The correlation coefficient formula is on page 186-187. You may also do the calculations with Excel.

In the formula, note that n refers to the number of pairs of measurements (or the number of subjects), not the total number of measurements.

Also note that the correlation coefficient has no units.

In the first set of calculations, make head length the x variable and head width the y variable.

In the second set of calculations, make head length the x variable and right arm circumference the y variable.

LAB SESSION 2:
DERMATOGLYPHICS

In this part of the lab we will assess a nonmetric dermatoglyphic trait: dermal pattern type of the fingers. Note that an individual may have several different dermal patterns on the digits. We'll use the six dermal pattern types described and illustrated by France.

Review pages 205-208 in France (2004).

Everyone will ink his/her partner's fingerprints on the charts provided in lab. Note on page 208 of France that in inking fingerprints, first roll the finger from side to side on the ink pad and then side to side on the paper. You'll also use the instructor's fingerprints to answer questions.

Ink your partner's fingerprints on the chart provided in lab. Do both hands. Be sure to put the individual's name on the chart. Allow the ink to dry before shuffling the paper.

We will work as a group to answer questions 1-4 of Exercise 11.4 on pages 207-208 in France (2004).

17. On your fingerprint chart, clearly indicate which type of dermal pattern you have on each digit. Use the six types defined and illustrated by France on page 206.

18. On the instructor's fingerprint chart, clearly indicate which type of dermal pattern she has on each digit. Use the six types defined and illustrated by France on page 206.

DUE DATE

Submit your completed answer sheet at the beginning of class on Wednesday, September 26.

Use a paperclip to attach your hand-written calculations or your Excel spreadsheet to your answer sheet.

GLOSSARY

allele - multiple/alternate expressions of a gene

anthropometry - the "physical measurement of human body form" (Molnar 1998)

chromosome - threadlike structures of DNA found in cell nuclei and bearing genes

congenital - a trait that is inborn

correlation - the relationship between two variables

correlation coefficient - "a measure of linear dependence or mutual relationship between two random variables, x and y" (France 1996:65)

dermal count - the number of dermal ridges

dermal ridge - a raised surface on the skin of fingers, toes, palms, and soles of the hands and feet

dermal ridge pattern - the shape of dermal ridges

dermatoglyphics - "[t]he study of patterns of dermal ridges present on the fingers and palms of the hands and toes and soles of the feet of humans and other primates" (France 1996:85)

descriptive statistics - numerical data that describe the character of a sample; includes measures of central tendency (mean, median, mode), standard deviation, and frequency distributions

frequency - the number of times a measurement occurs in a sample

gene - part of a chromosome that codes for a particular trait

landmark - a point on the body that can be located consistently by different people and is used in measuring metric body traits

mean - "the average of a set of measurements, calculated by adding the terms and dividing their sum by the number of terms" (France 1996:64)

metric trait - a characteristic of the human body that can be quantified; quantitative trait; measured with numbers

metacarpal - bones of the palm of the hand

nonmetric trait - a characteristic of the human body that cannot be quantified; qualitative trait; documented by presence or absence or type

normal distribution - "a probability distribution depicted graphically by a bell-shaped curve symmetrical about the mean" (France 1996:63); usually based on a minimum of 25 measurements

phalanges - bones of the fingers and toes

polygenic - traits controlled by more than one gene

population - total number of individuals in a group defined by some characteristic(s)

sample - a portion of a population

sliding caliper - a device for making linear measurements

spreading caliper - a device for making linear measurements around body protuberances

standard deviation - "a gauge of variation or spread within a set of measurements" (France 1996:64); the distribution of measurements around the mean

REFERENCES

France, Diane L.
2004 Lab Manual and Workbook for Physical Anthropology (5th ed.). West/Wadsworth, Belmont, CA.

Gould, Stephen Jay
1996 The Mismeasure of Man. W. W. Norton, New York.

Molnar, Stephen
2002 Human Variation: Races, Types and Ethnic Groups (5th ed.). Prentice Hall, Upper Saddle River, NJ.

Return to Modern Human Biological Variation Home Page

Visit the Western Kentucky University Home Page, Western Online
Page composed by Darlene Applegate, darlene.applegate@wku.edu
Last updated on September 7, 2007
All contents copyright (c) 2007. Western Kentucky University.