LOL, good snark, JL, keeps me on my toes! But in this particular case, the explanation is remarkably simple. That which is more important is the thing that appeared first in evolution, and has been preserved in each and every single case of a nasal passage occurance. Pretty obvious really. In each and every instance of nasal passages, we have a sense of smell. From the earliest examples. That is not true for many of the other functions, such as connected to lungs, since nasal passages exist even when there are no lungs present - such as in fish. Which I already highlighted, thus showing my work. That said, you are absolutely right, in different animals, the different functions of nasal passages are emphasized, possibly even surpassing the sense of smell(?). Thus in human beings, maybe other functions are more important than the sense of smell - I don’t know, though the sense of smell seems key even here, as the paper below states. But that wasn’t my point. My point was strictly focused on evolution - the claim that the nose evolution preserved those other functions preferetially - that obviously is not the case, as the most important function evolutionarily has been the sense of smell, as I showed above (being first, and present always).
Here is an interesting paper looking at the interplay of these very issues, and the olfactory aspect even in the human nose looks pretty robust, so my confidence in this is boosted (not that I have a deficit of self-confidence, as you note, lol):
https://journals.biologists.com/jeb/article/222/Suppl_1/jeb186924/2802/The-navigational-nose-a-new-hypothesis-for-the
Quote:
" If nose shape is under positive selection, then, barring the hypothesis of Dr Pangloss that the human nose evolved to hold up spectacles (Gould and Lewontin, 1979), we must consider the hypothesis that it could function in olfaction. Subtle changes in nasal anatomy can be associated with significant differences in olfactory function (Zhao, 2004). For example, the shape of the tissue immediately past the nostrils (i.e. nasal vestibule) can have a significant effect on the flow of air to the olfactory epithelium (Zhao and Jiang, 2014). There are large individual differences in this area, with some individuals showing a distinctive notch (Ramprasad and Frank-Ito, 2016). Because the perception of intensity for soluble odorants increases when airflow is lower (Sobel et al., 1999), Li et al. (2018) hypothesized that the notch would produce a vortex that would increase sensitivity to more soluble odors, which their results confirmed. Moreover, narrower noses had larger notches, more intense vortices and higher sensitivity to soluble odorants (Li et al., 2018). Thus, there may be local turbulence in specific regions in the nasal chamber that can influence olfactory as well as respiratory function (Zhao and Jiang, 2014).
An olfactory hypothesis
If structure influences sensory function, then this structure may be adapted to a specific use. In humans, the shape of the external ear can be predicted from the statistics of the auditory landscape (Parise et al., 2014). The relative size of the eye in birds and mammals scales with the speed of movement (Heard-Booth and Kirk, 2012). If human nose shape has an olfactory function, it may have been similarly shaped by its olfactory landscape.
One reason why there should be a relationship between olfaction, nose morphology and climate is that the conditions supporting olfaction are also climactic. Odorants may become easier to detect with increased absolute humidity because water molecules compete with odorant molecules for substrate positions (Igue et al., 1972; Vander Wall, 2003), although the exact relationship between humidity and the behavior of molecules can vary in complex ways (Emanuelsson et al., 2013). Laboratory studies of olfactory threshold in humans confirm that odors are easier to detect in conditions of higher humidity and temperature and lower barometric pressure (Kuehn et al., 2008). Thus, one might predict that using olfaction would be favored in hot, humid climates but not in climates that are cold, dry or found at high altitude. In fact, there is a positive association between nasal breadth and absolute humidity (Zaidi et al., 2017; Maddux et al., 2016).
The observation that nasal breadth associates with a climate conducive to olfaction may be a clue to an olfactory function for the human external nose: the use of odors in spatial orientation. The reason is that the use of olfaction in orientation makes specific demands on the external morphology of the olfactory sensors. This is because olfactory navigation is enhanced by using stereo olfaction, where paired olfactory sensors (antennae, nares) that can compare independent samples increase the accuracy of orientation to an odor source, as I will review below. Perhaps the evolution of the external pyramid in Homo is an adaptation for spatial olfaction and hence is another contribution to the integrated suite of adaptations for efficient long-distance travel that has been characteristic of the genus since Homo erectus."
