![]() 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.Microevolution – Evolution within a population.Mechanisms: the processes of evolution – Selection, mutation, migration, and more. ![]() The history of life: looking at the patterns – Change over time and shared ancestors.An introduction to evolution: what is evolution and how does it work?.Thus differences between humans and other apes in occipital morphology result from the intersection of three evolutionary trends in the hominin lineage: 1) brain size expansion, 2) reduction of the masticatory apparatus, and 3) upright posture and bipedal locomotion. The greater cerebral volume of humans results in vertically set parietotemporal walls, the greatest breadth of the cranial vault is positioned high on the parietals, and the mastoid region appears considerably less prominent. In apes the sides of the cranial vault (the parietotemporal walls) slope upwards and inwards from this wide base towards the top of the cranium. Second, in apes the greatest breadth of the cranial vault is found across the temporal bones near the base of the vault, giving the appearance of an inflated mastoid region. Humans have relatively small temporal and nuchal muscles (the former reflecting an overall reduction in the size of the masticatory apparatus, the latter related to upright posture that reduces the need for large neck muscles to counterbalance the head), whose attachments on the cranial vault do not form pronounced crests, and which do not share a compound line of attachment on the occipital. ![]() In most individuals, the temporal crest meets the nuchal crest, either at two locations on either side of the midline (as in most chimps) or continuously across the back of the cranium (as in gorillas), to form a prominent compound temporal/nuchal crest. First, apes tend to have prominent temporal and nuchal crests (although these features may be reduced in females of all species, or in bonobo males) that result from large chewing muscles and neck muscles (the latter important in maintaining head posture in a quadrupedal position) attaching to a relatively small neurocranium. Humans differ from other apes in the overall architecture of the occipital bone (the bone forming the posterior portion of the cranial vault), as evident when the skull is viewed from the back or side. ![]()
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