In Africa's Lake Victoria, researchers believe they've caught a fish population in the act of splitting into two distinct species. Researchers say this example of evolution-in-action is remarkable because the two sub-populations of fish aren't geographically isolated and could theoretically interbreed, but adaptations to their vision are causing them to diverge. Lead researcher Norihiro
Okada and his colleagues had previously shown that cichlid fish in Lake Victoria’s shallow waters are bathed in bluer light, while the turbid water of the lake predominantly lets redder light filter down to fish living in deeper water. The researchers showed that the fish’s eyes have adapted to this difference so that fish that live in deeper water have a pigment in their eyes that is more sensitive to red light, while shallow-water fish have a pigment that’s sensitive to blue [Science News].
Okada's new study, published in Nature [subscription required], shows that those eye ...
