Question
1.What evolutionary advantage is there for rods & cones to have multiple, stacked layers of membranes containing photopigments?
2.Foveal cones are spaced about 30 arc sec apart, and the optics of the eye actually spread a spot of light over an array almost 5 cones in diameter. However, position discrimination in humans (vernier acuity, two line separation acuity) is accurate to about 5.0 arc sec. How is this possible?
3.Why are there about 9 times more P ganglion cells than M ganglion cells? Does this mean, as David Hubel once claimed, that M cells are less important for vision?
