Lab 4 Hominins.pdf - ANT2511C Lab 4 | Hominins Harrison...

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Unformatted text preview: ANT2511C Lab 4 | Hominins Harrison Glover 6/21/20 Name _________________________________________________________ Date _____________________________ In this lab, you will evaluate the differences between early hominins through assessment of dentition, cranial features, and probable locomotion patterns. Exercise 1: Dentition ​30 points STEP 1: ​Measure the length and width of each tooth in specimens a-c in ​millimeters a ​ nd enter the data into the chart provided. STEP 2:​  Calculate the surface area for each tooth. Multiply the length by the width, and note the result in the space provided on the chart. STEP 3​  Calculate the surface area for all three teeth. For each mystery specimen, add the surface areas of all three teeth together and enter the result in the chart (on the next page). STEP 4​  Interpret the data. Use your completed chart (and the general dentition patterns discussed in this lab) to answer the following questions. Specimen Last Premolar First Molar Second Molar Total (all surface areas added together) in mm​2 2.6cm Length 1.4m Length 1.4cm Width 1.5cm Width 1.0cm Width 1.2cm Surface Area (length x width) 3.75 Surface Area (length x width) 1.4 Surface Area (length x width) 1.68 3.cm Length 2.0cm Length 2.7cm Width 2.8cm Width 1.5cm Width 2.0cm Surface Area (length x width) 8.4cm Surface Area (length x width) 3cm Surface Area (length x width) 5.4 2.7cm Length 2.0cm Length 2.3 Width 1.8cm Width 1.2 Width 1.4 Surface Area (length x width) 4.86 Surface Area (length x width) 2.4 Surface Area (length x width) 3.22 Specimen A Length Specimen B Length Specimen C Length 6.83 16.8 10.48 1. Which of the mystery specimens is a human? What evidence indicates this? Specimen B is a human because the dental formula matches that of modern day humans 2. Which of the mystery specimens is a gracile australopith? What evidence indicates this? Specimen A is a gracile australopith because their dental formulas match up and they have 3. Which of the mystery specimens is a robust australopith? What evidence indicates this? Specimen C is a robust australopith because their dental formulas and coloring match up. more teeth. Exercise 1 Specimen A Specimen B Specimen C ANT2511C Lab 4 | Hominins Exercise 2: Australopithecine Variation ​5 points 4. Which of these mystery australopiths is a later, more robust form? B 5. Describe at least two facial or cranial traits you used to make this determination. Be sure to describe how each trait appears in the two fossils. The two facial or cranial issues that helped me make the determination is the fact that the skull is patched with different colorings, and because it is longer Exercise 3: Australopithecus V H ​ omo sapiens ​5 points 6. Examine the Lucy (​ Australopithecus afarensis​) skeleton (left) Describe at least two postcranial (below the head) traits that indicate that Au. afarensis was adapted for bipedalism. One postcranial trait that indicates that Au. afarensis was adapted for bipedalism is the wideness of the pelvis bone, and the growth of the legs. 7. Compare the Lucy (​Au. afarensis​) skeleton with the human (Homo sapiens - right) skeleton. Describe at least two postcranial traits that differ between these species. Homo sapiens have longer arms than the Au. aferensis, they also have a less wide pelvis. 8. What do your answers suggest about the kind of bipedalism practiced by ​Au. afarensis​? The Au. aferensis would not be as good at commuting bipedally as Homo sapiens. Exercise 4: A ​ u. sediba​ V other A ​ u. ​5 points 9. Examine the A ​ ustralopithecus sediba​ skeleton (on separate page). Describe at least two traits that ​Au. sediba​ shares with other australopiths (such as​ Au. africanus​ or ​Au. afarensis​). Austalopithecus shares similar leg length with the Au. africanus, and similar pelvis width as the Au. afarensis. The 10. What do your answers suggest about the evolutionary relationship between these species? The Au. Sediba would be the oldest skeleton. Exercise 5: Stone Tools ​5 points 11. What type of tool is this? A stone tool 12. Describe the features of this tool that led you to identify it as this tool type. The material of the stone tool is bone, which is what most stone tools 13. What tool technology does this tool belong to? Oldowan technology 14. Name one fossil species that may have made this stone tool. Au. Gahri may have used that stone tool. are made of Exercise 2 Exercise 3 Au. afarensis Homo sapiens Exercise 4 Exercise 5 Au. afarensis Au. sediba ANT2511C Lab 4 | Hominins Exercise 7 ​25 points Foot Measurements: ​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). Scaled illustrations of a chimpanzee foot and an A ​ . afarensis​ footprint from Laetoli are provided below. 15. Trace your bare foot on a clean sheet of paper. 16. Using the provided scale, measure in cm the distances according to the instructions. Use the graph and record your results in the appropriate spaces. 17. Calculate the hallux divergence index by dividing the foot width by the foot length. Answer these questions based on your results. a. Did A ​ . afarensis​ have a divergent big toe? Yes b. Did A ​ . afarensis​ have a derived foot similar to modern humans, or a primitive foot more like that of an extant chimpanzee? Give a reason for your answer. No, its foot was similar to that of an extant chimpanzee because it had tree gripping capabilities. Cranial Measurements​: Determine whether the relative brain size of A ​ . afarensis​ was more similar to modern humans or modern chimpanzees. (Remember that the primitive condition is expected to be more like that of a modern chimpanzee). In this section of the activity, you will take 3 measurements: cranial width (the widest part of the skull), cranial length (the distance from the forehead just behind the eyebrows to the bac of the skull), and cranial height (the distance from the top of the cranium to just below the ear). Use the images in the chart as a guide. Estimate the cranial width, length, and height using the scale provided in the top right corner of the images. Record your results in the appropriate spaces. Calculate the cranial volume for the three specimens by multiplying the cranial width, cranial length, and cranial height by 1.333 x 3.14, then divide your answer by 10. 2 ​ 5 points 18. Was the brain size of ​A. afarensis​ more similar to modern humans or modern chimpanzees? What are you basing this on? The brain size of the A. afarensis is more similar to modern chimpanzees than it is to modern humans, because they are more similar in size. The size of the A. afarensis's brain is 500 cubic centimeters, which is 1/3 the size of a modern human brain. Exercise 6 Trace your foot (use a different sheet of paper if this page does not have enough room: Taxon modern human (you) Distance between hallux & 2nd toe 0.5cm Hallux Divergence Index Foot length Foot width Foot width/Foot length 26.5cm 9.0cm 0.339 24.0cm 9.0cm 0.375 22.0cm 11.5cm 0.522 A. afarensis 0.8cm modern chimp 3.2cm Taxon Cranial Width Cranial Length Cranial Height Multiply by Cranial Volume (cc) modern human (you) 14.2 17.6cm 12.5 x ​1.33 x 3.14 10 18.5 modern chimp 9.5cm 12.0cm 8.0cm x ​1.33 x 3.14 10 12.3 14.5cm 10.5cm x ​1.33 x 3.14 10 14.8 A. afarensis 10.5 ...
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