17 movement slower than 30 images per second, some bees and flies can track motion at up to 200 images per second! That’s why when you try to swat a fly, it sees your hand clearly in extreme slow motion! The Compound Eye of Mantis Shrimps While mantis shrimps are a common seafood on our dinner table, did you know that they also have a compound eye with photoreceptors that detect 12 colors from ultraviolet to red [8]? Surprisingly, these marine creatures are not good at differentiating colors. Humans can perceive colors in the whole visible spectrum because we have a well-developed brain to analyze the raw signals received from three types of color cones (red, green, and blue). By comparing the relative intensities of those signals, our brain can “mix” the three primary colors to perceive the colors of the rainbow. However, mantis shrimps can barely do so with their small brains [9]. They can only see discrete colors directly detected by those 12 photoreceptors. Across the ommatidia in their compound eye, only a thin band of six rows of ommatidia in the middle is responsible for color vision. As a result, they must physically roll their eyes to see the color of an object. Conclusion Ultimately, the diversity of eyes shows that sight never evolved all at once, but rather sculpted over 600 million years by the relentless pressure of survival. What began as a humble cluster of light-sensitive cells gradually specialized into an astonishing array of optical tools, from high-speed insect 引言 視覺是我們的重要感官。人類的眼睛極其發達，卻容 易被比下去：蒼蠅的視覺反應速度是我們的六倍，而瀨 尿蝦的色彩感知範圍則是我們的四倍 [1]。在漫長的演 化歷史中，大多數物種都發展出獨特的方式去觀察世界。 我們將探索一些視覺領域的先鋒與皇者。 怎樣才算視覺？ 「視覺」可以定義為透過結合眼睛的感光作用，與神 經系統的資訊整理，將偵測到的光線轉化為有關周圍環 境有用資訊的能力。由於缺乏處理資訊的神經結構，植 物和細菌雖然能探測並對光線作出反應，但通常不被視 為擁有視覺。 compound systems to the detail-oriented eyes of humans. In the grand theater of evolution, nature has spent eons proving that there is always more than one way to look at this fascinating world.
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