The stickleback fish did something in less than 10,000 years that would take other animals at least 100 times as long: It adapted its color vision to a new environment.
That was among the findings in a new study in the journal Proceedings of the Royal Society B by researchers from the University of British Columbia (UBC).
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The scientists compared the vision of two brands of stickleback – one ocean-faring, the other a freshwater relative.
They looked at each fish's sensitivity to different light wavelengths and found that while the marine sticklebacks were more sensitive to blue and ultraviolet light, the freshwater fish were more sensitive to wavelengths of light common in their murky lake-water environments, such as green and orange.
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Freshwater sticklebacks switched to lake life about 12,000 years ago, as the last ice age ended, meaning they put their vision adaptation into an evolutionary microwave oven, altering expression of a gene that handles light sensitivity in the eye.
"This is a very short time scale for large changes in color vision to evolve," said lead researcher Diana Rennison in a statement. "We'd typically expect species to adapt their vision over time spans in the millions of years."
That wasn't the end of the adaptive surprises, either. The scientists also noted that even within a given lake the sticklebacks were further modifying their vision to suit their localized light settings. That suggested to the team that they might be able to pull off the feat even faster than 10,000 years.
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How the stickleback sees colors impacts greatly its ability to see prey as well as predators. It also helps them find suitable mates.
"Color is hugely important in mate selection," said Rennison. "So these shifts in vision could play an important role in the generation of new species."
This is not the first time sticklebacks have been noted for their ability to adapt on the (relative) fly. Late last year a study found that the humble fish quickly changed its physical features in just 50 years, after a monster earthquake in Alaska in 1964 stranded some marine sticklebacks in freshwater ponds.