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Dichromatic color vision is enabled by two types of cone cells with different spectral sensitivities and the neural framework to compare the excitation of the different cone cells. The resulting color vision is simpler than typical human trichromatic color vision, and much simpler than tetrachromatic color vision, typical of birds and fish. A ...
This theory supports the evidence showing that trichromatic color vision originated in Africa, as figs and palms are scarce in this environment thus increasing the need for this color vision selection. However, this theory does not explain the selection for trichromacy polymorphisms seen in dichromatic species that are not from Africa. [22]
Trichromatic color vision is the ability of humans and some other animals to see different colors, mediated by interactions among three types of color-sensing cone cells. The trichromatic color theory began in the 18th century, when Thomas Young proposed that color vision was a result of three different photoreceptor cells .
Honeybees and bumblebees have trichromatic color vision which is insensitive to red but sensitive to ultraviolet. Osmia rufa, for example, possess a trichromatic color system, which they use in foraging for pollen from flowers. [50]
Researchers studying the opsin genes responsible for color-vision pigments have long known that four photopigment opsins exist in birds, reptiles and teleost fish. [3] This indicates that the common ancestor of amphibians and amniotes (≈350 million years ago) had tetrachromatic vision — the ability to see four dimensions of color.
Color blindness is any deviation of color vision from normal trichromatic color vision (often as defined by the standard observer) that produces a reduced gamut. Mechanisms for color blindness are related to the functionality of cone cells , and often to the expression of photopsins , the photopigments that 'catch' photons and thereby convert ...
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Thomas Young and Hermann von Helmholtz assumed that the eye's retina consists of three different kinds of light receptors for red, green and blue.. The Young–Helmholtz theory (based on the work of Thomas Young and Hermann von Helmholtz in the 19th century), also known as the trichromatic theory, is a theory of trichromatic color vision – the manner in which the visual system gives rise to ...