Given that all five of our special senses are built around cilia, how might we think about this fact from a teleological perspective? Well, all I can say is that this fits quite well within two primary themes that I have been fleshing out over the last couple of years.
First, if we wanted to front-load evolution such that the sense of sight and hearing are more likely to emerge when metazoan-type life emerges, then we would expect cilia to be quite ancient. And in fact they are – they are as old as eukaryotes themselves. In fact, the last common ancestor of all eukaryotes not only had cilia (or flagella), but probably had the complex system for ciliogenesis (a process known as intraflagellar transport).
Of course, I have long known about the ancient state of cilia, so let’s push it some more. Let us propose the original core function of cilia has always been sensory. In other words, while most people think of cilia as motility structures, this may be more of a secondary function. If the original function for cilia has always been sensory, then “the business end” of our five senses have always been there from the start of eukaryote existence.
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