After completing this exercise, you should be able to:
Compare and contrast the feet of several primates to identify bipedal abilities.
Bipedalism is the act of walking on two feet. This can be habitually or for brief periods of time. The ability to walk bipedally in an efficient manner depends on great changes to the structure of the body. One of those changes comes from the foot.
Anthropologists have argued about the bipedal abilities of our potential ancestors Australopithecus afarensis. Here you will compare your own foot to the foot of an Australopith and a chimpanzee to see where they fall. More human? More ape?
Determine whether A. afarensis had feet that more closely resembled modern humans or modern chimpanzees. (Remember that the primitive, or earliest, condition is expected to be more like that of a modern chimpanzee).
In this section of the activity, you will take three measurements: the distance between the hallux (big toe)
and the second toe, foot length (the length from the tip of the longest toe to the back of the heel), and foot width (the widest part of the foot usually around the toe area).
Actual size outlines of a chimpanzee foot and from an A. afarensis foot print preserved at Laetoli have
been provided for you.
1. Trace your bare foot on a clean sheet of paper (you can use the back of this lesson).
2. Using digital calipers or a ruler, measure in cm the distances according to the instructions.
Write your results in the space provided on the graph.
3. Calculate the hallux divergence index by dividing the foot width by the foot length.
4. Answer these questions based on your results:
What is bipedalism?
What are the earliest fossil hominins that show bipedalism?
What anatomical features are indicative of bipedalism?
Did Australopiths have a toe more similar to humans or apes? Give your reasoning.