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The evolution of bioluminescence in the deep sea has roughly 40 origins. The selective pressures of the deep sea where there is a lack of light, allowed for bioluminescence to flourish. Adaptations that were also selected for was the detection of blue light wave lengths. Bioluminescence in fish is often the product of symbiosis of fish and bioluminescent bacteria.

Evolution
Davis et al (2016) proved that bioluminescence has evolved independently 27 times within 14 fish clades across ray-finned fishes. Bioluminescence is not only present in ray finned fishes but also bacteria, dinoflagellates, radiolarians, ctenophores, cnidarians, molluscs, crustaceans, echinoderms and tunicates. It is most common among fish, squid and zooplankton. Although, not every organism has its own innate ability to emit bioluminescence. Some organisms adapted alongside bioluminescent symbionts. These organisms evolved symbiotic relationships, usually with bacteria, to be able to utilize bioluminescence in the deep sea.

Attraction
Bioluminescence is used in a variety of ways and for different purposes. The cirrate octopod Stauroteuthis syrtensis uses emits bioluminescence from its sucker like structures. These structures are believed to have evolved from what are more commonly known as octopus suckers. They do not have the same function as the normal suckers because they no longer have any handling or grappling ability due its evolution of photophores. The placement of the photophores are within the animals oral reach, which leads researchers to suggest that it uses it bioluminescence to capture and lure prey.

Defense
The defense mechanisms for bioluminescent organisms can come in multiple forms; startling prey, counterillumination, smoke screen or misdirection, distractive body parts, burglar alarm, sacrificial tag or waning coloration. The shrimp family Oplophoridae Dana use their bioluminescence as a way of startling the predator that is after them. Acanthephyra purpurea, within the Oplophoridae family, uses its photophores to emit bioluminescence and also is able to secrete it when in the presence of a predator. This secretory mechanism is common among fish who are more often prey rather than predators.