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UVlight
onic development they are in the possession of a notochord and pharyngeal
clefts. After metamorphosis the notocord is lost and the nerve cord degenerates. The main characteristic is that the body is enclosed in a strong thick
protective skin, the tunica. The main internal part of the body is a large perforated branchial sac, that is used for sieving water to collect food. This subphylum is divided in three classes: Ascidiacea, Thaliacea, and Larvacea (syn.
Appendicularia), which are all marine.
US Exploring Expeditions ~Wilkes Expedition.
UV light ultraviolet light, the part of the electromagnetic spectrum with wavelengths of 200 to 400 nm. Depending on the physiological effects, ultraviolet
light is classified as UV-A (320-400 nm), UV-B (280-320 nm) and UV-C
(200-280 nm). The shorter wavelengths, with higher energy, are more harmful to living organisms. Ultraviolet light, especially the wavelengths shorter
than 290 nm, is absorbed and reflected in the atmosphere. The ozone layer
in the stratosphere is responsible for the absorption of short-wave UV light;
it is therefore of fundamental importance to life on earth. Due to human
activities, the ozone layer above the polar regions is gradually eroding
(ozone holes) and more and more UV-B radiation reaches the earth's surface.
UVlight
onic development they are in the possession of a notochord and pharyngeal
clefts. After metamorphosis the notocord is lost and the nerve cord degenerates. The main characteristic is that the body is enclosed in a strong thick
protective skin, the tunica. The main internal part of the body is a large perforated branchial sac, that is used for sieving water to collect food. This subphylum is divided in three classes: Ascidiacea, Thaliacea, and Larvacea (syn.
Appendicularia), which are all marine.
US Exploring Expeditions ~Wilkes Expedition.
UV light ultraviolet light, the part of the electromagnetic spectrum with wavelengths of 200 to 400 nm. Depending on the physiological effects, ultraviolet
light is classified as UV-A (320-400 nm), UV-B (280-320 nm) and UV-C
(200-280 nm). The shorter wavelengths, with higher energy, are more harmful to living organisms. Ultraviolet light, especially the wavelengths shorter
than 290 nm, is absorbed and reflected in the atmosphere. The ozone layer
in the stratosphere is responsible for the absorption of short-wave UV light;
it is therefore of fundamental importance to life on earth. Due to human
activities, the ozone layer above the polar regions is gradually eroding
(ozone holes) and more and more UV-B radiation reaches the earth's surface.