User:Ochampsi

Wikipedia Article Selections
The first article that requires reviewing is the one on Mantis Shrimp. This article lacks information on the specific way in which mantis shrimp see circular polarized light. Although the article mentions their ability to visualize this form of light, it does not describe the mechanisms used in visualizing it. The addition of this information will improve the understanding behind the way circular polarized light is visualized by these creatures.

The second article that I feel requires review is the article on Circular Polarization. This article lacks information regarding the species that are able to visualize circular polarized light. In this article, there is a section that mentions the Mantis Shrimps ability to produce circularly polarized light. The addition of information pertaining to their ability to visualize circular polarized light and its benefits would improve the understanding of the importance of this form of vision.

The third article that requires reviewing is the article on Ommatidium. This article lacks information on the ommatidiums ability to convert circular polarized light into a detectable visual signal. This update would be interesting, as it would compare the arrangement of the R cells in regular non-circular polarized viewing oomatidia to oomatidia capable of visualizing circular polarized light. The mantis shrimps ability to convert and view circular polarized light would be used as an example of this. This information will increase the breadth of knowledge currently covered in this Wikipedia article and will provide readers with insight into the complexity of the oomatidia.

Article to review: Mantis Shrimp
Wikipedia’s mantis shrimp page covers a broad range of topics spanning from the ecology of the species to their behavior in their respective environments. The topic page also touches on the complexity of the mantis shrimps eyes. In this section the authors describe the broad range of visual fields which the mantis shrimp can see, including one of their most recently discovered visual capacities—the ability to see circular polarized light. However, they do not touch on the mechanisms and structures within its eye responsible for according it this extraordinary visual capacity. The article simply mentions that species of mantis shrimp have been reported to have this visual capability. This is where I feel the Wikipedia article is lacking information. I believe that an explanation on the mechanisms and structures underlying this visual capacity will help readers understand and appreciate this new discovery. By describing these specific mechanisms and structures, readers will be able to learn the types of morphology grant these shrimp this form of vision. Furthermore, I feel that the addition of this information will place a greater emphasis on the mantis shrimps ability to view circular polarized light.

There are three resources I feel would be beneficial for this articles improvement.

Chiou et al. (2008) address the structural basis behind the mantis shrimps ability to visualize circular polarized light. Some key points were:
 * Photoreceptivity in stomatopod crustaceans in mantis shrimp requires specific alignment of microvilli
 * Stomatopods have visual units known as oomatidia
 * In each oomatidium a single retinular cell designated R8
 * The R8 cell is centrally positioned over and optically coupled to the R1-7 cells
 * The R1-7 cells in this region are intrinsically detect linear polarized light

Kleinlogel et al. (2008) describe the orientation and morphology of various components in the 5th and 6th mid-band oomatidia which contribute to the mantis shrimps ability to visualize circular polarized light.
 * The orientation and morphology of the R8 and R1-7 cells in oomatidia of the 5th and 6th row mid-band region are distinct from those in the other rows and regions of the mantis shrimps eye
 * R1-7 cells here are wider and more crystalline in appearance and their microvilli are thinner
 * The R8 cell, a four-lobed cell that surrounds a light guide which directs light at the R1-7 cells, is ovoid and extends substantially further down the light guide than the R8 cells in other oomatidia
 * The R8 cells in the 5th and 6th mid-band rows are oriented 45° about the axis of the R1-7 cells
 * These structural properties of the R8 cell induce a phase shift in the light passing through it

Cronin et al. (2009) discuss the significance of the phase shift caused by the R8 cell. Additionally, they describe the role of the R8 cell within the oomatidia of the 5th and 6th rows of the mid-band region in the mantis shrimps eye, as a quarter-wave retarder. Lastly they demonstrate the complexity of the R8 cell by describing its ultraviolet detecting features.


 * The R8 cell in this region of the mid-band acts as a quarter wave retarder
 * The significance of a quarter-wave retarder is that it induces a phase shift in the light and converts the circular polarized light into linear polarized light which can then be detected by the R1-7 cells
 * This retarder is made from a series of unidirectional, parallel microvilli that are birefringent and sit above linear polarization receptor cells R1-7
 * The R8 cell also contains an ultraviolet-sensitive visual pigment, this gives it the capability to function as an ultraviolet photoreceptor