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Adaptation (eye) In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher ...
Cold and heat adaptations in humans are a part of the broad adaptability of Homo sapiens. Adaptations in humans can be physiological, genetic, or cultural, which allow people to live in a wide variety of climates. There has been a great deal of research done on developmental adjustment, acclimatization, and cultural practices, but less research ...
Human skin color. Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics (inherited from one's biological parents), exposure to the sun, disorders, or some combination thereof.
Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vision compared to many animals such as cats, dogs, foxes and rabbits, in part because the human eye lacks ...
An animated sequence of simulated appearances of a red flower (of a zonal geranium) and background foliage under photopic, mesopic, and scotopic conditions. The Purkinje effect or Purkinje phenomenon (Czech: [ˈpurkɪɲɛ] ⓘ; sometimes called the Purkinje shift, often pronounced / p ər ˈ k ɪ n dʒ i /) [1] is the tendency for the peak luminance sensitivity of the eye to shift toward the ...
Visual phototransduction is the sensory transduction process of the visual system by which light is detected by photoreceptor cells (rods and cones) in the vertebrate retina.A photon is absorbed by a retinal chromophore (each bound to an opsin), which initiates a signal cascade through several intermediate cells, then through the retinal ganglion cells (RGCs) comprising the optic nerve.
Dark skin. Dark skin is a type of human skin color that is rich in melanin pigments. [1][2][3] People with dark skin are often referred to as black people, [4] although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations. [5][6][7][8] The evolution of dark skin is ...
Light skin. Light skin is a human skin color that has a low level of eumelanin pigmentation as an adaptation to environments of low UV radiation. [1][2] Due to migrations of people in recent centuries, light-skinned populations today are found all over the world. [2][3] Light skin is most commonly found amongst the native populations of Europe ...