1. Compare the position of the ischium to the acetabulum in Homo sapiens, Pan troglodytes, and Australopithecus, shown in Figure 10.1. Also, describe the length of the iliac crest, general shape of the coxal bone, and curvature in the sciatic notch for each of the three specimens. Is the Australopithecus specimen more like that of humans or chimps? Why?
2. What differences exist between the coxal bones of Australopithecus afarensis and Australopithecus africanus pictured in Figure 10.2? How might bipedalism differ between these two early bipeds?
3. Compare the femur and humerus of Homo sapiens and Pan troglodytes in Figure 10.3. What differences do you observe? How might these differences relate to locomotion? Why are humans described as ‘knock-kneed' compared to the apes?
4. What differences exist between the sacral bones of Homo erectus and Australopithecus afarensis shown in Figure 10.4? Which species arrived first? What can we determine about the nature of bipedalism by comparing these two?
5. Compare the proximal tibiae of Pan troglodytes and Homo sapiens pictured in Figure 10.5. Which knee joint is absolutely larger and why? How might this relate to bipedalism?
6. Observe the foramen magnum in Pan troglodytes and Homo sapiens shown in Figure 10. 6. Which species has a relatively larger foramen magnum? What does the position and form of the foramen magnum suggest about the locomotion of these two species? Look, also at the shape of the jaws of both specimens. What distinguishes the two?
7. Identify and describe the distinguishing aspects of the cranium of Sahelanthropus tchadensis (Figure 10. 7). Are the supraorbital tori (brow ridges), facial shape and cranium size apelike (Compare to figures 10. 8, 10.9), humanlike, or neither? What are some implications of your answer, for hominin evolution?
8. Classification
A. Explain the difference between a ‘traditional' system of classification, vs. a system based on cladistics.
B. Now, arrange the bones from 10.7, 10.8, 10.9 and 10.10, using a traditional system, then arrange them using a cladistics system. Depending on where you place the different items, what does this tell you about the nature of relationships between the different specimens?
Pictures- https://www.dropbox.com/s/hopi3ws5qm6ll25/Assgn.zip?dl=0