I was curious as to what would happen if we were missing a single type of cone. It seems intuitive that we wouldn't see the colors that corresponds to that type of cone, and it looks like that is what happens. Dogs for example, only have cones that are receptive to blue and yellow, so dogs aren't able to distinguish red.
Individuals who are color blind are hypothesized to have faulty or missing cones or have a bad pathway between the cones in the eye and the brain.
I am confused why the eye responds more to the M cones than the L cones? since the average human eye can perceive wavelengths from 400-700.
^ I don't think it's necessarily that the eye responds more to the M cones, it's just that the M and L cones have significantly overlapping spectral responses - i.e. they both are used to perceive light from ~500-600 nm. Checkout this article http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html on the breakdown of the types/numbers/response functions of cones.