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. 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) Vampire Squid (Vampyroteuthis infernalis) 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. • http://www.youtube.com/watch?v=9frgs8lU Nac Copy these questions down, and answer in your notes Bioluminescence Questions 1. How is bioluminescence produced? 2. List six creatures that emit bioluminescence 3. Describe the three reasons why creatures in the ocean use bioluminescence. 4. What colour is most bioluminescence and what is an exception? 5. Why might creatures emit a bioluminescence liquid?