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Posts Tagged ‘Darwin’
Eyes and Evolution: Why Do Some With Eyes See Not?
In the great satirical movie Duck Soup (first released 79 years ago to the date of this post), Mrs. Gloria Teasdale (Margaret Dumont), the financial underwriter of the nation of Freedonia, recruits Rufus T. Firefly (Groucho Marx) to be the insolvent country’s new president. The opposition then retains two spies, Chicolini (Chico Marx) and Pinky (Harpo Marx), to work for them. Toward the end of the film, in a bedroom scene with Teasdale, the spies both dress like Firefly in order to secure the combination to a safe. After she gives the combination to one Firefly (the disguised Pinky), Mrs. Teasdale watches him leave the room, but suddenly another Firefly (the disguised Chicolini) appears. Teasdale confronts Chicolini who denies leaving and blusters “Well, who you gonna believe, me or your own eyes?” He knew that Teasdale had convincing evidence against him. She was, after all, an eye-witness. And yet, she did not understand.
Perhaps more than on any other of our senses, humans rely on sight. Our camera eyes allow massive amounts of information to enter our brain, first through the lens at the exterior of the eye, and then from the inverted image on the retina at the back of the eye by way of the optic nerve. In the plains of Africa, our ancestors stood to gather information about their surroundings. Today we focus on ironically named smartphones, not so much to hear audio transmissions, but to stare at screens with text or other visual data.
So important is sight to us that over two-thirds of the sensory cells in our bodies are the light sensing cells in our eyes. So energy consuming is the human retina that it uses more oxygen per gram than does the brain. (Shubin, Your Inner Fish (Pantheon Books 2008), at 150; Lane, Life Ascending (W. W. Norton 2009) at 175.) read more