Monday, August 03, 2009


Living things which are capable of creating their own light are called 'bioluminescent'. Science has known ever since William Beebe explored the darkness of the deep ocean that many deep sea marine species have glowing spots in strategic places or patterns on their bodies. Terrestrial species with similar abilities continue to be discovered. Many of these are small invertebrates and fungi, usually hidden from view in the dense rainforest vegetation, leaf litter or in the soil. Finding new species during the light of day is difficult enough. Finding a newly discovered species with abilities that can only be seen in the dark can be even more difficult.

How does a living thing create light?
Presented as simply as possible, bioluminescence occurs when the luciferase enzyme and the chemical luciferin react. A third element needs to be present for this reaction to take place which varies according to the type of animal or fungus. For example, in fireflies and glow worms, ATP is required; for jellyfish, calcium would be needed; and peroxide for earthworms. Oxygen is also sometimes required. Whatever the exact reactants are for each animal or fungus, the end result is the release of energy in the form of light.

Why would a living thing want or need to create light?
The chemical reaction described above and the resultant unstable by-product are often referred to by the experts as 'an excited state'. In some cases, this may be a clue as to why an animal might be bioluminescent but the situation is different for each type of animal that has the ability to glow. For fireflies, the ability to glow is useful for attracting mates. The glow worm has a better chance at a full dinner because it uses its pale green light to draw in a curious, unsuspecting meal.


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