incisors and canines) than posterior teeth (i.e. The extant species of Pan, like other extant apes, are distinguished by their pronounced supraorbital tori and long projecting lower faces that house relatively larger anterior teeth (i.e. The facial skeletons of Homo sapiens and its closest living relatives in the genus Pan differ considerably. The major evolutionary trends in the hominin lineage subsequent to the LCA are discussed in relation to the dental arcade and dentition, subnasal morphology and the size, position and prognathism of the facial skeleton. It is not possible to determine with any confidence whether the facial morphology of any of the current candidate LCA taxa ( Ardipithecus kadabba, Ardipithecus ramidus, Orrorin tugenensis and Sahelanthropus tchadensis) is representative of the LCA, or a stem hominin, or a stem panin or, in some cases, a hominid predating the emergence of the hominin lineage. Consequently the list of hypothetical features expected in the face of the LCA is very limited beyond its hypothesized similarity to extant Pan. These include the prevalence of homoplasy and poor phylogenetic resolution due to a lack of defining derived features. Some of the problems involved in reconstructing ancestral morphologies so close to the formation of a lineage are discussed. boisei also outdoes us in that department.This review uses the current morphological evidence to evaluate the facial morphology of the hypothetical last common ancestor (LCA) of the chimpanzee/bonobo (panin) and human (hominin) lineages. Our teeth are dwarfed by those of our close relatives - and though we have thicker enamel than some of our relatives, Au. Where do modern humans fit in? Well, we seem to be the geeky cousin in need of braces. Whatever this species was eating must have been pretty tough! Furthermore, its skull was configured to provide attachments for huge chewing muscles. boisei had massive grinding teeth with a thick coating of enamel and diminutive front teeth. Australopithecus boisei, on the other hand, lived 1.7 million years ago and seems to have done something unusual with its teeth.anamensis individuals still had large canines. They could have eaten a more varied diet than ramidus. Reprinted by permission from Macmillan Publishers Ltd.įour million year old Australopithecus anamensis had larger, sturdier molars and much thicker enamel than Ard. Reprinted by permission from Macmillan Publishers Ltd.Īrdipithecus ramidus, who walked the Earth 4.5 million years ago, sported relatively small molars (though still bigger than ours), with enamel intermediate in thickness between chimps and later hominids, and large (though not apelike) canines. How did the teeth of our close relatives measure up? Here’s a rundown of some our relatives with distinct dentitions: Human and chimp dentition photos provided by the eSkeletons Project.īut modern humans and chimps are just two surviving branches on what was once a more diverse family tree. Human teeth (left) and chimpanzee teeth (right). Human molars are covered by a thick layer of enamel (much thicker than that of a chimp), which lets us grind up tough foods and protects our teeth from unpleasant (and hard) surprises in our diet - like un-popped popcorn kernels. But at least we have them beat in the enamel department. Information on controversies in the public arena relating to evolutionĬompared to our evolutionary cousins, the chimpanzees, humans have wimpy teeth - our tiny spade-shaped canines, small incisors, and reduced premolars and molars are very different from a chimp’s dentition.Alignment with the Next Generation Science Standards.The big issues – Pacing, diversity, complexity, and trends.Macroevolution – Evolution above the species level.
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