For the human eye the range of electromagnetic waves defined as visible light is approx. 380 to 770 nm, but the most pronounced and recognizable waves range between 520-565 nm, which is the range of the green colour. In these wavelengths we see the most detail and contrast as well as the biggest amount of visible shades. Could our humanoid ancestors develop this ability to better orient themselves in the dense forests in the course of evolution?
The human colour recognition mechanism is based on 3 types of cones, roughly responsible for responding to blue (short wave), green (medium wave) and red colour (long wave). However, this development is rather recent. The eyes of human predecessors were based on two cone types and only by duplicating and slight change of their genes responsible for the green responsive cone we can now see the red colour well. The ranges of the green and red responsive cones still differ very little and largely overlap, thus giving a double reading of various shades of green. Researchers argue that the development of the third, red responsive cone could have had a serious impact on the ability to distinguish ripe and unripe fruits (thus improving skills in gathering) and to facilitate the social life of our ancestors. Don’t the lovers get a red blushed face because they are “ripe” to love?