15 Do You See What I See? A Guide to Nature's Wildest Eyes 看到我所見的嗎？ 大自然最神奇的眼睛指南 By Daria Zaitseva Introduction Vision is an important sense we have. The human eye is often regarded as highly advanced, yet we are easily outperformed: A fly's visual response is sixfold faster than ours, and a mantis shrimp's range of color vision is quadruple our own [1]. Along the long history of evolution, most species developed their unique ways of looking at this world. We will explore some pioneers and champions of vision. What Counts as Vision? “Vision” can be defined as the biological ability to detect and convert light into meaningful information about the environment by combining photoreception in the eye with neural processing in the nervous system. Because of the lack of neural processing element, plants and bacteria are not generally considered to have vision, although they can perceive and react to light. How Did Vision Come About? Before we delve into how vision first came about, we must consider cells that are sensitive to light. These simple photoreceptors can only sense whether light is present; they cannot “see” clear images without a lens and a sufficiently complex nervous system to process visual information [2]. These light sensors can drive basic functions like phototaxis, the movement toward or away from light, and circadian rhythm, the internal biological clock of an organism. Along the evolution to a more complicated eye, the flat neural tissue containing photoreceptors sinks inward, creating a small dip called a pigment cup [2, 3]. This indentation changes the physics of light collection: On a flat surface, light from all directions can reach the photoreceptors simultaneously, but once the patch curves
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