![]() ![]() They point forward when the fish is feeding. ![]() The eyes point upward (as shown here) when the fish is looking for food overhead. The fish’s tubular eyes are capped by bright green lenses. ![]() With this information we can begin to trace the variation within the system, including the possibility of uncovering how this system evolved.The barreleye ( Macropinna microstoma) has extremely light-sensitive eyes that can rotate within a transparent, fluid-filled shield on its head. In the groups that produce their own light, we want to get the mRNA from the light organs themselves. “We’ll catch fishes and look at their mRNA to see what genes are being expressed. “We need fresh specimens for modern genetic approaches,” he says. In May, Smith and his two colleagues returned after taking a chartered vessel to sea from the West Coast to collect samples of bioluminescent fish for analysis. To follow this line of inquiry, Smith and his coauthors now are working with a grant from the National Science Foundation to identify specific genes associated with the production of bioluminescence in fish. “When they start using bioluminescence for species recognition, they diversify into a lot more species.” Skin lets these fish do a vanishing act “In the ocean, there are no physical barriers to separate groups of deep sea fishes, so why are there so many species of anglerfishes, for example? “Many fish proliferate species when they evolve this trait-they differentiate, but we don’t know why,” Smith says. Sparks of the American Museum of Natural History found all fish they examined evolved bioluminescence between the Early Cretaceous, some 150 million years ago, and the Cenozoic Era.įurther, the team shows that once an evolutionary line of fish developed the ability to produce light, it tended soon thereafter to branch into many new species. “Estimates of the size are thousands of trillions of bristlemouth fish in the world’s oceans.” An evolutionary advantage? “The bristlemouth is the most abundant vertebrate on Earth,” Smith says. The most common vertebrate species on the planet lives within this habitat and is bioluminescent. “So this tells us bioluminescence is almost a requirement for fishes to be successful.” “You have this whole habitat where everything that’s not living at the top or bottom of the ocean or along the edges-nearly every vertebrate living in the open water-around 80 percent of those fish species are bioluminescent. “When things evolve independently multiples times, we can infer that the feature is useful,” Smith says. Smith says the huge variety in ways bony fish can deploy bioluminescence-such as leveraging bioluminescent bacteria, channeling light though fiber-optic-like systems or using specialized light-producing organs-underlines the importance of bioluminescence to vertebrate fish in a major swath of the world’s deep seas called the “deep scattering layer.” Different squid evolved to glow in similar way He added that some fish also are thought to use bioluminescence as camouflage. Leo Smith, assistant curator with the University of Kansas Biodiversity Institute, who coauthored the study in PLOS ONE. “Bioluminescence is a way of signaling between fishes, the same way that people might dance or wear bright colors at a nightclub,” says W. Indeed, the authors show with genetic analysis that bioluminescence has evolved independently 27 times in 14 major fish clades-groups of fish that come from a common ancestor. Most people are familiar with bioluminescence in fireflies, but the phenomenon is found throughout the ocean, including in fishes. And it seems they have a variety of ways to glow.īut how bioluminescence evolved in fishes is still a bit of a mystery. Scientists say bioluminescence-the production of light from a living organism-is more widespread among marine fishes than they thought. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |