Question

1.Many of the traits we learned about in this lab have had a lasting effect on our lineage, and as a human, you still bear their consequences today. For example, humans are at high risk of knee injuries, such as tears in the ligaments that support the knee joint between the femur and tibia. What adaptation that traces back to australopiths, like Lucy, might put additional strain on your knee? Why would a trait with such negative consequences have evolved?

2.In this lab, we reviewed numerous fossil species and their defining characteristics. To help you make comparisons across these species and understand larger trends in our evolutionary history, review the species discussed in this lab and answer the following questions.

Part i. In what geographic region(s) have numerous early hominin discoveries been made? How do those regions relate to the locations of the pre-australopith species that came before them?

Part ii. Review the australopith and early Homo behaviors and compare them with what you know about pre-australopiths. What behaviors are documented in australopiths and Homo habilisthat are not seen in pre-australopiths? Why might these behaviors appear in the more recent species and not in the pre-australopith group?

Part iii. Choose one gracile australopith species and one robust australopith species, and list at least two traits that distinguish them. Also list at least two things they have in common. What do your answers suggest about their classification and relationship to each other?

Part iv. Choose any australopith species and compare it withHomo habilis. List at least two traits that distinguish these species. What do your answers suggest about their classification and relationship to each other? Which one are you more closely related to (with which do you have more in common)?

Answer 1

ANSWER 1 :-

1. First of all, the Australopithecus is the ancestor species of the modern humans (Homo sapiens). The humans are more susceptible to knee injuries. Lets make a comparison between a bent posture as can be seen in case of Gorillas and Chimpanzees and an erect posture which is stated to have originated in the Australopithecus. This posture is responsible for differences in terms of adding extra burden onto the knees.
2. The presence of three important ligaments namely the anterior and posterior cruciate ligaments aligning the condyles of the bones and the Middle collateral ligament are involved in restricting the movement of the knee in conjunction with the bones thereby bearing more stress and becoming susceptible to ligaments.
3. Apart from this, the most important conclusion to be noted that the human and Australopithecus limb bones shows characteristic feature and structural similarity mainly projecting the presence of the tibia bone being oriented perpendicular to the horizontal axis. Apart from this, due to less motion being mediated by the ligaments mentioned above, the angle of rotation is highly reduced and therefore becomes more prone to injuries thereby reflecting the answer to the query. This ability to walk on both the legs have enabled the humans to do a variety of movements and activities which include running, walking, etc at the expense of balancing the body. The skeleton that has been considered in this discussion is of Australopithecus afarensis and the name of the specimen is Lucy.

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