Activity 4: Bipedal Adaptations

1. Recall that the human pelvis (show below right) looks very different from a chimpanzee pelvis (show below left). Examine the pelves below. Ont the chimpanzee and Australopithecus pelves, trace the orientation of the iliac blades, their width and height, and the width of the sacrum.  We have done this for you on the human pelvis, which you can use as a guide. Then, fill in the chart below and answer the questions.

     a. Does Australopithecus appear to have more chimpanzee-like or human-like pelvis           morphology?

     b. Based on your answer, what would you say about the locomotion of Lucy?

2. Recall that humans have a valgus knee as a result of a bicondylar angle that tilts the shaft of the femur toward the body's midline. We've drawn the human bicondylar angle on the image blow to illustrate this point.

a. Why is a bicondylar angle important for a biped?

b. Print out this image (left) and draw the bicondylar angles for A. afarensis and a chimpanzee. To draw the angle, first draw a line perpendicular to the blue line, starting at the green dot. Then, draw a line through the middle of the femur's shaft.

c. Based on your drawing, does the Australopithecus femur exhibit a more human-like or more chimp-like bicondylar angle?

d. What can you conclude about the locmotion of Lucy based on your answer?