Re. Mr. Miles' letter, the Eye. Man on average is five to six feet tall, so many generally would be looking down to plant and to harvest. He would generally be looking ahead to hunt or take a walk, so he generally does not need to look great distances.
Of course if his bags are packed and headed south, generally he is looking down from say 10 to 200 feet. Let's say a red tail hawk is 200 feet up, looking for lunch.
Oh, there is a mouse sunning itself and of course it comes in against the sun (now shadow). Zoom, zoom, caught ya.
Now here's a blob sitting in a pool of water and it thinks, "I need to see." It has this ping pong ball sitting on it, and it says, "I'm going to make an eye." The complexity of that happening for me is mind-blowing.
"If we were to attempt to duplicate the computing power of the human eye, we would have to build the world's most advanced computer with a single enormous silicon chip (usually the size of a dime) that would cover 10,000 cubic inches and contain billions of transistors and hundreds of miles of circuit traces. The retina is so small - 0.0003 inches - that to build a device to mimic the eye, the chip would weigh at least 100 pounds. In comparison, the retina weighs less a gram. It operates on less than 0.0001 watts of electrical charge. To duplicate the retina's abilities, the imaginary computer would consume at least 300 watts of power. In other words, the retina is three million times more efficient in its power consumption." - John Stevens, Byte Computer Magazine, April 1985.
God and a scientist were talking about life in general when the scientist reached down and grabbed some dirt. God asked him, "What are you doing?" The scientist said he's going to make a man and God said, "Get your own dirt." Why would the mouse need the eye of a hawk or the other way around?