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Moving one eye to the other side of the head |
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Written by Boldone
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Wednesday, 30 July 2008 |
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An apparent evolutionary conondrum has been recently solved by the study of some Eocene fossils related to the flatfishes. Matt Friedman of the Chicago University, an expert of fish evolution, has published in a Nature paper his work on the ancestors of Pleuronectiform fishes (plaices and the akin gastronomical delicatessen).
The origin of the exceptional asymmetry shown by flatfishes, acquired in the adult after moving during ontogeny one eye to the other side of the head, has fueled debates on the role of natural selection vs saltatory change on evolutionary theory. The study of Amphistium and Heteronectes now shows that intermediate forms have existed, giving credit to a slower natural selection than previously thought by advocates of the saltatory change.
References
Friedman M. 2008 - The evolutionary origin of flatfish asymmetry. Nature 454, 209-212.
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