Please answer the questions in the handout below

Please answer the questions in the handout below. You can earn up to 10 extra credit points, which will be added to your midterm II score. Please note that you can not exceed 100 points on the exam. Even if you do not want to turn it in for extra credit, I strongly urge all of you to do it as it will be helpful in identifying what anatomical traits defines a hominin. Use the lecture from this week as your guide to help answer the questions. 

• To earn the 10 points, please turn it in by Sunday, November 15th at 11 pm - I will post a key for the assignment the following week.
• Access document here: Extra Credit, Midterm II.pdf

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  Extra Credit, Midterm II A hominin is a taxonomic term used to describe bipedal primates within the family Hominidae. The earliest hominins had anatomical traits that resembled humans in some ways, but they also retained many primitive traits. How can we tell if a hominin is truly a hominin? We know that humans and our extinct hominin ancestors are the only habitually bipedal primates to have existed. We can therefore use the feature of bipedality as one of the most significant characteristics of the hominin family when looking at some of the many trait’s fossils can provide for us. Exercise 1: Bipedal locomotion and defining characteristics of the hominins – fill in the correct answers in the tables Part A Feature: The Foot Ape Hominin Curved or flattened phalanges? Convergent (in-line) or divergent big toe? Longer or shorter phalanges? Arche under foot? Part B Feature: Pelvis & Femur Ape Hominin Iliac blade? (short/wide or long/narrow) Bowl shaped pelvis (yes or no) Femur: Bicondylar angle? (angled or straight?) Part C Feature: Skull & Spine Ape Hominin Foramen magnum position? (anterior, centralized or posterior) Canine size? (big or small) Apical wear (tip wear) on canine? Diastema? (yes or no) Exercise 2 Sahelanthropus tchadensis is a 6-7 mya fossil skull found in Chad and may be the oldest known hominin fossil. Using your knowledge of defining hominin characteristics, evaluate the fossil specimen for hominin features and answer the questions that follow. Please indicate unknown if the information is not known. Feature Sahelanthropus tchadensis Brain size? 350 cc Position of foramen magnum? Canine size? Diastema? Double arched foot? Curves in spine? Bowl shaped pelvis? Angled femur? a. Based on the information above, why has Sahelanthropus tchadensis been classified as a hominin? b. Do you see any complications with the classification? Concept Review 1. How do we define a hominin? 2. Why is it important for a hominin to have a more centralized/ anterior foramen magnum position? 3. What does the shape of the pelvis indicate about its function in hominins? 4. Why is the shape of the hominin foot different from that of the apes? 5. The dentition of the earliest hominins is relatively primitive and mostly ape-like, but their post-crania is distinctly human-like. What does this tell you about the rates of evolution in various parts of the body? 6. Which evolved first: the hominin brain, the bipedal hindlimb, or the human dentition?