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Vision itself relies on a basic biochemistry which is common to all eyes. However, how this biochemical toolkit is used to interpret an organism's environment varies widely: eyes have a wide range of structures and forms, all of which have evolved quite late relative to the underlying proteins and molecules. [24]
Night vision is of lower quality than day vision because it is limited in resolution and colors cannot be discerned; only shades of gray are seen. [1] In order for humans to transition from day to night vision they must undergo a dark adaptation period of up to two hours [ 2 ] in which each eye adjusts from a high to a low luminescence "setting ...
The gene-centered view of evolution, gene's eye view, gene selection theory, or selfish gene theory holds that adaptive evolution occurs through the differential survival of competing genes, increasing the allele frequency of those alleles whose phenotypic trait effects successfully promote their own propagation.
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.
The early writers discussed here treated vision more as a geometrical than as a physical, physiological, or psychological problem. The first known author of a treatise on geometrical optics was the geometer Euclid (c. 325 BC–265 BC).
While color vision is dependent on many factors, discussion of the evolution of color vision is typically simplified to two factors: the breadth of the visible spectrum (which wavelengths of light can be detected), and; the dimensionality of the color gamut (e.g. dichromacy vs. tetrachromacy).
According to the Snake Detection Hypothesis, venomous and life-threatening snakes, including asp vipers, were crucial for the evolution of primates' visual systems.. The snake detection theory, [1] [2] [3] also sometimes called the snake detection hypothesis, suggests that snakes have contributed to the evolution of primates' visual system.
Microsaccades are a kind of fixational eye movement.They are small, jerk-like, involuntary eye movements, similar to miniature versions of voluntary saccades.They typically occur during prolonged visual fixation (of at least several seconds), not only in humans, but also in animals with foveal vision (primates, cats, dogs etc.).