Vision is the sense by which we and other animals obtain most of our information about the world around us. Darwin appreciated that at first sight it seems absurd that the human eye could have evolved by natural selection. But we now know far more about vision, the many times it has independently evolved in nature, and the astonishing variety of ways to see. The human eye, with a lens forming an image on a sensitive retina, represents just one. Scallops, shrimps, and lobsters all use mirrors in different ways. Jumping spiders scan with their front-facing eyes to check whether the object in front is an insect to eat, another spider to mate with, or a predator to avoid. Mantis shrimps can even measure the polarization of light.Animal eyes are amazing structures, often involving precision optics and impressive information processing, mainly using wet protein - not the substance an engineer would choose for such tasks. In Eyes to See, Michael Land, one of the leading world experts on visio
