Honors Bellringer 1/10

The Galapagos Island of Santiago experienced a year long drought. This resulted in much fewer small seeds with thin seed coats. The number of large seeds with thick seed coats was unaffected. How did this phenomenon change the population of seed eating birds? What type of beaks would you expect would be predominant in the next generation of offspring?

Physical Anthropology: Calculating an index

PART I (Practice calculating and using an index)The general method of calculating an index is to divide one measurement by another. When comparing two objects, you must measure the same distances on each object. Often one measurement is multiplied by 100 first, in order to provide a larger number. Then this number is divided by the other measurement.

1.Calculate an index of width to length of the rectangle below by following the steps a, b, and c below. Record your measurements and calculations on the student data sheet.a. Using the metric ruler, measure side “a”—record length in data chart!!b. Measure side “b”—record length in data chart!!!c. Calculate the index of width to length by dividing (a x 100) divided by b.

Show work: (a x 100) = Write this number in b your data chart

2.Now calculate the width to length index for the rectangle below by following rectangle using the same steps as in #1.a. Using the metric ruler, measure side “a”—record length in data chart!!b. Measure side “b”—record length in data chart!!!c. Calculate the index of width to length by dividing (a x 100) divided by b.

Show work: (a x 100) = Write this number in b your data chart

3. Compare the three objects below. Which two have the similar shape? Check your answer by calculating the index of width to length for the three objects. Record your measurements in the student data sheet Part I.a. Using the metric ruler, measure side “a”—record length in data chart!!b. Measure side “b”—record length in data chart!!!c. Calculate the index of width to length by dividing (a x 100) divided by b.

Show work: (a x 100) = Write this number in b your data chart for each Figure

REPEAT steps (a), (b) and (c) for all three Figures!!

PART II. PHYSICAL ANTHROPOLOGY: COMPARING FOSSIL HOMINIDS

(Calculating a cranial index)

• Indices can also be calculated for objects with irregular shapes, like skulls.

• This activity involves looking at several different skulls and measuring different features that anthropologists use to compare modern humans to earlier humans.

• Anthropologists compare skull features of cranial height to cranial length. You will make this same comparison in this investigation by measuring the cranial height and then dividing this measurement by the cranial length. The result is an index.

PROCEDURE – PART II• Examine each skull, then use the calipers and metric rulers to

measure the cranial height and cranial length of each skull. • Measure the cranial height from the posterior side of the

foramen magnum to the highest point on the top of the skull. *• Measure the cranial length from the most protruding point

above the eyes to the most protruding point on the backside of the skull *

4. Record your measurements for each skull in the student data table.

5. Calculate the index for each skull and record it in the student data table.

Cranial Index = Cranial Height x 100 Cranial Length

Final Questions!!!

At this point you are finished with the lab!! However…You must now analyze your data!

Please finish the last five questions about the lab on your student data sheet. Glue this lab sheet onto page 4 when it is complete.