ancestors the humankind odyssey walking on two legs

On this basis, gibbons and siamangs are generally accepted to form a clade very distinct from all other living crown hominoids, whose members fall into the family-level taxon Hylobatidae. But, genetic distances and branching sequences are usually regarded as equivalent, although few studies have sought to establish concordances between the two approaches (Lockwood et al. Even so, relationships within the crown hominoids are not easy to establish unequivocally on shared-derived morphological characters. This means that several higher taxa of fossil apes, such as the Proconsulidae, are root-hominoids, not closely related to the living apes or to fossil crown hominoids of similar age, such as Morotopithecus. a transversely broad, not dorsoventrally deep thorax. The living apes and their fossil relatives are all members of an informal group, the crown hominoids, conservative in craniodental features but readily defined by shared-derived characters of the postcranium, e.g. It would be next to impossible to find any scientist who is not a creationist who would regard that implication as correct. Since grade-based systematics are now almost universally rejected, under phylogenetic systematics this would imply that humans and their fossil relatives are members of one daughter lineage of the last common ancestor (LCA) we share with other apes, and that all other apes belong to another. 2014) have been guilty of contrasting ‘human’ with ‘ape’ anatomy, with the (however inadvertent) implication that human anatomy is so distinct from that of all other living apes that they can all be lumped together on a different, lower rung of the ‘scala naturae’. Nevertheless, the very Victorian philosophy of progress at the heart of the ‘scala naturae’ concept, which itself underlies grade-based approaches, is still all too pervasive: most of us at one time or the other (e.g. It has replaced older approaches based on perceived shifts in ‘levels of organization’ (grades) which were dominant in the 1950s and 1960s. Phylogenetic systematics, which identifies biological groups (clades) by shared-derived (synapomorphic) characters, is now the accepted method for analysing mammalian relationships. However, selection for ecological plasticity and morphological conservatism is a core characteristic of Hominidae as a whole, including Hominini. The late split date of the panins, corresponding to dates for separation of Homo and Australopithecus, leads to the speculation that competition with chimpanzees, as appears to exist today with gorillas, may have driven ecological changes in hominins and perhaps cladogenesis. These data, together with evidence for continued arboreal competence in humans, mesh well with an increasing weight of fossil evidence suggesting that a mix of orang-utan and gorilla-like arboreal locomotion and upright terrestrial bipedalism characterized most australopiths. It now appears that the dominance of terrestrial knuckle-walking in mountain gorillas is an artefact seen only in the extremes of their range, and that both mountain and lowland gorillas have a generalized orthogrady similar to that seen in orang-utans. However, evidence that neither the knuckle-walking or vertical climbing of these apes is mechanically similar to human bipedalism, as well as the hand-assisted bipedality and orthograde clambering of orang-utans, has cast doubt on this paradigm.

This paradigm has been popular, if not universally dominant, until very recently. In the 1960s, however, with recognition of the close genetic relationship of humans, chimpanzees and bonobos, and with the first field studies of mountain gorillas and common chimpanzees, it was assumed that locomotion similar to that of common chimpanzees and mountain gorillas, which appeared to be dominated by terrestrial knuckle-walking, must have given rise to human bipedality. In the early 20th century the dominant paradigm for the ecological context of the origins of human bipedalism was arboreal suspension.

Ancestors the humankind odyssey walking on two legs