Visual pigments and environmental light

摘要: The visual pigments in the rods do not have a special absorption that gives them maximal sensitivity. of "deep sea" fish are an exception for these match environmental light to give maximum At low intensities at which operate, it is number photons go make up each element image limits ability eye discriminate detail and contrast. Chemically induced isomerisation pigment molecule may cause spurious signals limit detect contrasts very dim light. In bright become insignificant compared true photon-induced signals. Compared rods, cone spectral properties environment except there appear be no with beyond 625 nm porphyropsins cones. U.V. absorbing know invertebrates, birds live shallow water. Animals photoreceptors parts body other than eyes. vertebrates sites include pineal, chromatophores, brain, skin harderian gland. There evidence based on immunocytochemistry action spectra least some pineal receptors contain pigments, but like those quality