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BIOLUMINESCENCE. What is Bioluminescence?. The production of light by living organisms as a result of a chemical reaction either within certain cells or organs OR outside the cells in some form of excretion. Produced by the compound luciferin and the enzyme luciferase.
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What is Bioluminescence? • The production of light by living organisms as a result of a chemical reaction either within certain cells or organs OR outside the cells in some form of excretion. • Produced by the compound luciferin and the enzyme luciferase.
Who is lighting up in the ocean? • Bacteria • Dinoflagellates • Jellyfish • Squid & Octopus • Annelids (worms) • Krill & Shrimp • Seastars, Brittlestars, Sea Cucumber
In the deep ocean, where sunlight is absent, more than 90% of the animals are luminescent !!! Krill
Annelid (segmented worm). Lives 3000 m below surface. Ctenophore Deiopea Comb Jelly Dinoflagellates
Small Squid Enlargement of Photophores (light emitting organs)
Anglerfish Dragonfish Hatchetfish
So….why do they do it? Finding or attracting prey • Fish such as the anglerfish use a light organ filled with bacteria that dangles from their forehead. • Prey are attracted to the light in the same way that a fisherman might use a glowing lure for night fishing. • Some fish use bioluminescence as a flashlight. They use light, produced by symbiotic bacteria living in an organ below their eyes, to light up potential prey.
Defence against predators • Can serve as a decoy. Some squid and shrimp produce a luminescent glowing cloud. • When attacked by a predator, brittlestars sacrifice a part of the body that continues to flash as the animal makes its escape. • Where the sunlight is dim, it can be used as camouflage. • Many small plankton use flashes of light to startle their predators in an attempt to interrupt their feeding.
Communication / Mating • Attract opposite sex. • Bristle worms use bioluminescence during mating swarms, where the males will attract females to them. • Crustaceans send out coded messages when it is time to mate. This octopod uses its bioluminescence as a private signal for mating. Light is produced only at certain times, by a ring around the mouth of females.
Are bioluminescent animals found only in the ocean? • There are a few species on land. • Fireflies during the summer in North America. • Glow worms (actually fly larvae) in New Zealand. • Railroad worms (actually beetle larvae) in South and Central America. • But, bioluminescence is not found in freshwater lakes or rivers.
Copy these questions down, and answer in your notes Bioluminescence Questions • How is bioluminescence produced? • List six creatures that emit bioluminescence • Describe the three reasons why creatures in the ocean use bioluminescence. • What colour is most bioluminescence and what is an exception? • Why might creatures emit a bioluminescence liquid?