![]() In more recent humans, the transition from being hunter-gatherers to settlers also coincides with changes in the face, specifically the face becoming smaller. For instance, some early hominins had bony structures that suggested the presence of powerful muscles for mastication, or chewing, and they had very large chewing teeth, indicating that they were likely adapted for processing harder objects. Compared to our closest living relatives, the chimpanzees, our faces are more retracted and are integrated within the skull rather than being sort of pushed in front of it.ĭiet has been considered as an important factor, especially when it comes to the mechanical properties of foods consumed-soft versus hard objects. We also have less prominent brow ridges, and our facial skeletons have more topography. In broad terms, our faces are positioned below the forehead, and lack the forward projection that many of our fossil relatives had. How does the human face differ from that of our predecessors-and our closest living relatives? Journal reference: PLoS Computational Biology, DOI: 10.1371/ News asked Lacruz to describe how we came to look the way we do. “If you don’t assume that were cold-adapted, the shape of the aperture isn’t confusing, because that was simply inherited unchanged from their common ancestor,” Rae says. But Rae and his colleagues have argued that this might be because Neanderthals actually evolved and adapted in relatively warm and humid conditions before later moving into Europe. The Neanderthals are an apparently glaring exception to this rule – they lived in cold Europe yet had large wide noses. Narrow nostrils, the thinking goes, create more turbulence in the inhaled air, which increases the level of heat and moisture exchange between the air and the tissue covering the wall of the nasal cavity. “Europeans, on the other hand, have a narrower aperture, which has been assumed to be an adaptation for living in colder climates.” “There is a general trend for people in the tropics to have a wide nasal aperture,” he says. Our long pharynx is often linked to our ability to talk, but Nishimura says that it also plays an important role in conditioning inhaled air.ĭespite the new findings, Todd Rae at the University of Roehampton, UK, says we shouldn’t write off the idea that noses adapted to the climate that their owners inhabited. In particular, the pharyngeal region of the throat – which is much longer in humans than in other primates – may have begun to lengthen at this time. This may have made up for any inefficiency in the nose and nasal cavity, allowing humans to fully condition the air they inhaled. Brains grew and faces became relatively smaller to make room – and it is possible that the nose and nasal cavity were forced into their current shape to accommodate these changes.įortunately, given that the climate fluctuated in Africa around the time that true humans first appeared, making good air conditioning vital, other parts of the human airways changed too. The hominin skull underwent a dramatic reorganisation with the appearance of true humans from our Homo genus between 2 and 3 million years ago. He thinks we may have gained our protruding noses and poorly performing nasal passages simply by chance. “This indicates our protruding nose has few contributions to air-conditioning in the nose and nasal cavity,” says Nishimura. In fact, even when the researchers artificially manipulated the computer-generated human noses to look more like the flat ones of chimpanzee, the air-conditioning performance didn’t improve. The results suggest that the nasal passages of chimps and macaques condition inhaled air much more effectively than our nasal passages do. Then, using computers, they modelled the flow of inhaled air through the nasal passages.įinally, they calculated how efficiently these flow patterns would condition three different air types: cold and dry, hot and dry, and warm and wet. ![]() They took scans of the nose and nasal cavity of six human volunteers, four chimpanzees and six macaques. But Takeshi Nishimura at Kyoto University, Japan, and his colleagues argue that the human nose performs this job poorly. ![]()
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