The navigational nose: a new hypothesis for the function of the human external pyramid
Autor: | Lucia F. Jacobs |
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Rok vydání: | 2019 |
Předmět: |
Physiology
Olfaction Nose Aquatic Science 03 medical and health sciences Human nose 0302 clinical medicine medicine External nose Animals Humans Pyramid (image processing) Olfactory navigation Molecular Biology Ecology Evolution Behavior and Systematics 030304 developmental biology 0303 health sciences Communication biology business.industry Hominidae biology.organism_classification Biological Evolution Smell medicine.anatomical_structure Insect Science Animal Science and Zoology Homo erectus business 030217 neurology & neurosurgery Function (biology) Spatial Navigation |
Zdroj: | Journal of Experimental Biology. 222 |
ISSN: | 1477-9145 0022-0949 |
Popis: | One of the outstanding questions in evolution is why Homo erectus became the first primate species to evolve the external pyramid, i.e. an external nose. The accepted hypothesis for this trait has been its role in respiration, to warm and humidify air as it is inspired. However, new studies testing the key assumptions of the conditioning hypothesis, such as the importance of turbulence to enhance heat and moisture exchange, have called this hypothesis into question. The human nose has two functions, however, respiration and olfaction. It is thus also possible that the external nose evolved in response to selection for olfaction. The genus Homo had many adaptations for long-distance locomotion, which allowed Homo erectus to greatly expand its species range, from Africa to Asia. Long-distance navigation in birds and other species is often accomplished by orientation to environmental odors. Such olfactory navigation, in turn, is enhanced by stereo olfaction, made possible by the separation of the olfactory sensors. By these principles, the human external nose could have evolved to separate olfactory inputs to enhance stereo olfaction. This could also explain why nose shape later became so variable: as humans became more sedentary in the Neolithic, a decreasing need for long-distance movements could have been replaced by selection for other olfactory functions, such as detecting disease, that would have been critical to survival in newly dense human settlements. |
Databáze: | OpenAIRE |
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