Anatomical features Essay Example | Topics and Well Written Essays - 500 words

Anatomical features - Essay Example Radiometric analysis gives ‘Ardi’’s age as 4.4 million years, making her the oldest known hominid species to date. Ardi’s skeleton suggests a unique versatility and provides evidence of both biped and quadruped locomotion. The study of Ardi’s feet shows the markedly splayed big toe which facilitates the grasping of tree limbs, marking her as a quadruped in the trees. However, the presence of a small bone inside a foot tendon, which is absent in both chimps and gorillas, increases the rigidity of the big toe. This feature, in combination with other toe modification, promotes biped locomotion on the ground. Similarly, the pelvis shows both the large flaring upper bones which facilitate steady bipedality, and the lower pelvis which accommodates the huge hind limb muscles used in climbing like an ape. Again, unlike the strictly rigid wrist bones of chimps and gorillas, which are geared towards hanging from trees and knuckle-walking on the ground, Ardiâ⠂¬â„¢s highly flexible wrists and finger joints indicate that Ardi walked on her palms on tree limbs – like primitive apes. (Shreeve. October 1, 2009. National Geographic News). The most famous fossil remains of Australopithecus afarensis are the skeleton, "Lucy" found at Hadar, Ethopia, in 1974, the infant found at Dikika, Ethiopia, in 2006, and the 3.7 million years old footprints found in volcanic ash plus fossil bones found at Laetoli, Tanzania in 1978. The anatomical features in all these cases suggest that Australopithecus afarensis was capable of both bipedal and quadruped locomotion. Lucy’s long arm bones, and the ridge formed by the tendons attached to the humerus, indicate the strong chest and upper arm muscles required for tree climbing. However, her short, broad pelvis supported her upright body and her angled-in thigh bones maintained her weight directly above her knees – both optimum features for walking. Likewise, while Lucy’s compact,