![]() This view is widely accepted, even though morphological support seems stronger for an African great apes clade: chimps and gorillas share numerous characters that are absent in modern humans, such as thin enamel on the teeth, an enlarged trigonid basin on the lower molars, six sacral vertebrae and ten adaptations for knuckle-walking (Andrews, 1992), but these are presumably convergences or were present in the last common ancestor. Within the great ape clade, the molecular evidence has shown repeatedly that chimps are closest to humans, then gorillas and then the orang-utan. ![]() In a cladogram of the apes (cladogram (a)), most anthropologists accept that Proconsulidae is the basal taxon, followed by the gibbons (Hylobatidae) and then the great apes and humans, Hominidae (Andrews, 1992 Delson et al., 2002). The relatively late split of humans and apes was confirmed in the 1980s and 1990s by restudy of existing ape fossils, and by collection of new specimens of Proconsul, Dryop-ithecusand Sivapithecus which showed they were side branches from the line to modern apes and humans. At first, these dates were regarded as gross underestimates by anthropologists, but tests of the phylogenies using a dozen different proteins and the nucleic acids (DNA, RNA) produced comparable results (Goodman et al., 1998). 34-5) in the 1960s and 1970s showed that humans were much more similar to chimps and gorillas than had been expected, and the branching point was dated at about 5 Myr ago (range of estimates, 9-4 Myr ago). Early attempts at protein sequencing (see pp. This view was challenged dramatically by the findings of molecular biologists. ![]() ![]() The split between apes and humans was dated at 15-25 Myr ago, thus in the late Oligocene or early Miocene. Until about 1980, most anthropologists assumed that humans formed a distinct lineage from the great apes, with forms such as Sivapithecus being placed on the direct line to humans. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |