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The Amblyopsidae are a fish family commonly referred to as cavefish, blindfish, or swampfish.They are small freshwater fish found in the dark environments of caves (underground lakes, pools, rivers and streams), springs and swamps in the eastern half of the United States.
Living in darkness, pigmentation and eyes are useless, or an actual disadvantage because of their energy requirements, and therefore typically reduced in cavefish. [ 14 ] [ 15 ] [ 16 ] Other examples of adaptations are larger fins for more energy-efficient swimming, and a loss of scales and swim bladder .
Eigengrau is perceived as lighter than a black object in normal lighting conditions, because contrast is more important to the visual system than absolute brightness. [4] For example, the night sky looks darker than Eigengrau because of the contrast provided by the stars.
At depths of 4,000–6,000 m (13,000–20,000 ft), [2] this zone remains in perpetual darkness. [ 3 ] [ 4 ] It covers 83% of the total area of the ocean and 60% of Earth's surface. [ 5 ] The abyssal zone has temperatures around 2–3 °C (36–37 °F) through the large majority of its mass. [ 3 ]
Absolute darkness 10 −4: 100 microlux 100 microlux: Starlight overcast moonless night sky [1] 140 microlux: Venus at brightest [1] 200 microlux: Starlight clear moonless night sky excluding airglow [1] 10 −3: 1 millilux: 2 millilux: Starlight clear moonless night sky including airglow [1] 10 −2: 1 centilux: 1 centilux: Quarter Moon 10 − ...
The term echolocation was coined by 1944 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. [1] [2] As Griffin described in his book, [3] the 18th century Italian scientist Lazzaro Spallanzani had, by means of a series of elaborate experiments, concluded that when bats fly at night, they rely on some sense besides vision, but he did ...
Darkness is the condition resulting from a lack of illumination, or an absence of visible light. Human vision is unable to distinguish colors in conditions of very low luminance because the hue -sensitive photoreceptor cells on the retina are inactive when light levels are insufficient, in the range of visual perception referred to as scotopic ...
streams flow through the darkness. To be attached to things is illusion; To encounter the absolute is not yet enlightenment. Each and all, the subjective and objective spheres are related, and at the same time, independent. Related, yet working differently, though each keeps its own place. Form makes the character and appearance different;