In a new study published Wednesday in the journal PLOS ONE, it is said that bioluminescent marine ray-finned fishes have independently evolved their light at least 27 times. Therefore meaning that bioluminescence-the ability that has a living organism to produce and emit light is more widely spread among marine creatures than scientist had previously thought.
According to PLOS, the findings represent a new way of thinking about the evolution of glowing creatures in the deep sea. Previous research has calculated that the trait that makes this fish’ light had evolved only 40 times in the animal tree of life, which also includes the fireflies and fungi. With this new study, scientists consider that they have underestimated the marine life evolution.
These creatures are called bioluminescent animals because of their ability to create their light. Some of these creatures produce bioluminescence by myriad chemical reactions. While others animals have developed symbiotic relationships with bioluminescent bacteria, others have done just fine without it.
This new study reveals that the glow fish have evolved certain mechanisms in their bodies that allow them to control the light produced by the bacteria. It is said that the species studied by Roje and Smith have the ability to turn on or off the bacteria’s light as they need it. In a nuclear and mitochondrial gene fragments analysis taken from over 300 taxa, researchers found out more about the independent evolutionary origins of bioluminescence.
How did bioluminescent fish evolve?
According to Sparks, a curator at the American Museum of Natural History’s Department of Ichthyology and a co-author on the paper, in the ocean there are no physical barriers to keep different groups from reproducing with one another. This made the team of researchers questions how did reproductive isolation happened since isolated groups are needed to become new species. The researchers found out bioluminescence may have a lot to do with the development of deep-sea diversity
Previously, scientist considered that bioluminescence had evolved only 40t times in the entire animal tree; however, this new study unveils that this ability has arisen independently over 27 times in deep sea creatures, 150 million years ago. The findings state that this ability to produce its light not only help fish to camouflage but also to communicate with other animals and to attract prey. For example, some deep-sea anglerfish of the bathypelagic zone emit light from their esca as a way to lure their victims. He says that this evolution has branched off into many more species that scientist would have expected.
“If they’re able to use that light to communicate, they can be using that as a genetic isolating mechanism for sexual selection or species recognition,” Sparks said.
To this moment, available cameras cannot capture the exact colors emitted by fish, therefore their research was based on trawled up fishes from the depths.
He complains that studying fish glow in the lab is not the same as studying it in real live. Many fish have the sophisticated light mechanism that is linked to their organs, so in certain situations, they have the ability to turn them on or off. For Sparks studying these creatures in their natural environment would give him a better insight to understand how bioluminescence evolved so many times.
Building up a new camera to study glow-in-the-dark
Nevertheless, in April 2016, researchers have developed a new camera to simulate the way some species look at each other in blue light. To study these species such as the inflorescent Chain Catshark, researchers used a unique lens to see how the glow grows stronger and more distinct in a shark’s movements.
“We’ve already shown that Catsharks are brightly fluorescent, and this work takes that research a step further, making the case that fluorescence makes them easier to see by members of the same species. This is one of the first papers on fluorescence to show a connection between visual capability and fluorescence emission, and a big step toward a functional explanation for fluorescence in fishes” said Spark.
Since it is impossible for the human eye to appreciate the real colors of fluorescent deep-sea creatures, this new camera had a color filter to mimic fishy vision that allowed researchers understand how the fluorescence pooped in animals. David Gruber, a researcher at Baruch College, City University of New York and the American Museum of Natural History, told National Geographic that these sharks have a unique ability to attract prey that the human eye cannot see it.
“Imagine being at a disco party with only blue lighting, so everything looks blue. Suddenly, someone jumps onto the dance floor with an outfit covered in patterned fluorescent paint that converts blue light into green. They would stand out like a sore thumb. That’s what these sharks are doing.” he said.
Source: Washington Post