Design of Life

It's tempting to call it the "big bang" of colour vision.

Colour vision may not be a recent development. Working with jawless fishes, which are believed to most closely resemble the earliest vertebrates of the Lower Cambrian period 540 million years ago, O. S. E. Gustafsson, S. P. Collin and R. H. H. Kröger recently concluded that "the last common ancestor of all vertebrate lineages possessed a complex colour vision system" and that the system evolved "very early."

The history of photography and television shows a long stage of black and white images prior to the development of colour. It would be interesting to know whether that history influenced some researchers to think that colour vision would appear later, rather than early in life's history.

Citation and abstract:

Citation: Early evolution of multifocal optics for well-focused colour vision in vertebrates O. S. E. Gustafsson, S. P. Collin and R. H. H. Kröger Journal of Experimental Biology 211, 1559-1564 (2008) | doi: 10.1242/jeb.016048 http://jeb.biologists.org/cgi/content/abstract/211/10/1559

Abstract: Jawless fishes (Agnatha; lampreys and hagfishes) most closely resemble the earliest stage in vertebrate evolution and lamprey-like animals already existed in the Lower Cambrian [about 540 million years ago (MYA)]. Agnathans are thought to have separated from the main vertebrate lineage at least 500 MYA. Hagfishes have primitive eyes, but the eyes of adult lampreys are well-developed. The southern hemisphere lamprey, Geotria australis, possesses five types of opsin genes, three of which are clearly orthologous to the opsin genes of jawed vertebrates. This suggests that the last common ancestor of all vertebrate lineages possessed a complex colour vision system. In the eyes of many bony fishes and tetrapods, well-focused colour images are created by multifocal crystalline lenses that compensate for longitudinal chromatic aberration. To trace the evolutionary origins of multifocal lenses, we studied the optical properties of the lenses in four species of lamprey (Geotria australis, Mordacia praecox, Lampetra fluviatilis and Petromyzon marinus), with representatives from all three of the extant lamprey families. Multifocal lenses are present in all lampreys studied. This suggests that the ability to create well-focused colour images with multifocal optical systems also evolved very early.