Anna Wu
Source: Science Daily
Author: Monash University
Date: January 9, 2015
Link to article
Summary: In many wild and domestic animal species, several physical differences including color variations can be observed. Thus the prominent question of why certain colors don't replace others through the evolutionary process of natural selection. Will Sowersby, a PhD student at Monash University and his research group agrees upon the fact that although color morphs signify biological variation, the adaptive significance and the evolutionary processes that maintain them still remains unknown. To find an answer, the Monash research group looked at the red devil cichlid, a Central American freshwater fish which is found in two colors: gold and grey. The grey fish can alter its body color and camouflage into its specific environment, and is also more commonly found than the gold fish. To test if this camouflage ability is linked to color variation, researchers filmed the two colors of the red devil cichlid over light and dark surfaces. Screenshots were taken and analyzed to measure the amount of change in the fishs' body color. The researches discovered that only the grey fish have the ability to change color, and the gold fish cannot. From these results it was concluded that the ability to camouflage could be a potential factor in maintaining color frequencies within species.
Connection: This article pertains to Unit 1 and our current unit, Unit 7. The dark grey fish are at an advantage because of their camouflage ability, which connects to ecology and the relations between an organism and its environment. Because they are able to camouflage, it is a possibility that there is a increased chance in survival and decreased chance in getting consumed compared to the brighter gold fish. This is when natural selection, which we have studied in Unit 7, comes into play. It is given to us in this species of red devil cichlid, there are more grey fish found in the wild than gold fish. This could possibly be because not as many grey fish are being consumed as they are not as easily spotted. If this trend continues, it is possible that one day there will only be grey-colored fish in the red devil cichlid species because it contains the desirable traits for its enviornment. In other words, the natural selection will lead to adaptation, which will therefore lead to the evolution of an entire species.
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ReplyDeleteIs the gene/genes which allow the darker fish to alter their brightness present in the gold fish as well, and if so why would it be turned off?
ReplyDeleteThe gene is most likely present in the gold fish as they are one species of fish. There are two potential responses to why they cannot camoflauge.
ReplyDelete1) The gold fish may possess the gene and even have the ability of alter brightness, but because of their bright color, the camoflauge might not be as evident.
2) Again, the gold fish have the gene but the amount of color change may not be as high as the dark fish.
If the genes were in fact turned off, it is unlikely that it was because of natural selection as dark fish have a higher rate of survival. Rather, it may have been because of artificial selection. Locals may have been attracted to the gold fish ahd the intensity of their scales, so they bred them.