ancestors the humankind odyssey walking on two legs

During Miocene evolution, there appeared several fossil primates showing, to various degrees, adaptations for an orthograde posture (Nakatsukasa et al. Moreover, neither dinosaurs nor ostriches or any other sauropsid or marsupial moving on their hind feet show an orthograde spine in locomotion (Niemitz 2004). Even among all land-dwelling vertebrates, human bipedalism is unparalleled, since erect-walking penguins, with their short rudder-like feet, have a completely different functional anatomy and biomechanics (cf. The habitual orthograde human posture and locomotion using harmonic cycles of anatomical pendulums are unique among all mammals (e.g., Gebo 1996 Schmitt 2003 Vaughan 2003). The new synthesis presented here is able to harmonise many of the hitherto competing theories. This is consistent with paleoanthropological findings and with functional anatomy as well as with energetic calculations, and not least, with evolutionary psychology. So far, this is the only scenario suitable to overcome the considerable anatomical and functional threshold from quadrupedalism to bipedalism. In contrast to all other theories, wading behaviour not only triggers an upright posture, but also forces the individual to maintain this position and to walk bipedally. The forests were not far from a shore, where our early ancestor, along with its arboreal habits, walked and waded in shallow water finding rich food with little investment. The Amphibian Generalist Theory, presented first in the year 2000, suggests that bipedalism began in a wooded habitat. Moreover, the fossil remains revealed increasing evidence that this part of human evolution took place in a more humid environment than previously assumed. During the 1990s, the fossil record allowed the reconstruction of emerging bipedalism more precisely in a forested habitat (e.g., as reported by Clarke and Tobias (Science 269:521–524, 1995) and WoldeGabriel et al.

Secondly, they were all placed into a savannah scenario. Meanwhile, it has been established that all main hypotheses published until the last decade of the past century are outdated, at least with respect to some of their main ideas: Firstly, they were focused on only one cause for the evolution of bipedality, whereas the evolutionary process was much more complex. The most important and recent ones are discussed here. Ardipithecus inhabited woodland environments feeding on fruits, nuts, roots and small animals.During the last century, approximately 30 hypotheses have been constructed to explain the evolution of the human upright posture and locomotion. The apes discovery, along with other Miocene apes. Ardi, unlike modern hominids, had adaptations for both walking on two legs (bipedality) and life in the trees (arboreality). They evolved around 4.4 million years ago million years ago. Īrdipithecus ramidus is a species of australopithecine from the Afar region of Early Pliocene Ethiopia. This contradicts the open savanna theory for the origin of bipedalism, which states that humans learned to walk upright as climates became drier and environments became more open and grassy.Īlong with Ardipithecus, Ardi's wooded habitat also including some animals that weren't featured in Ancestors such as Dinofelids, gompatheres and chalicotheres. A good sample of canine teeth of this species indicates very little difference in size between males and females in this species.Īrdi’s fossils were found alongside faunal remains indicating she lived in a wooded environment.

The discoverers argue that the ‘Ardi’ skeleton reflects a human-African ape common ancestor that was not chimpanzee-like. The pelvis, reconstructed from a crushed specimen, is said to show adaptations that combine tree-climbing and bipedal activity. The foot bones in this skeleton indicate a divergent large toe combined with a rigid foot – it's still unclear what this means concerning bipedal behavior. Ardipithecus ramidus was first reported in 1994 in 2009, scientists announced a partial skeleton, nicknamed ‘Ardi’.

Ancestors the humankind odyssey walking on two legs