Visão de polarização circular em um crustáceo estomatópode: mero acaso, fortuita necessidade ou design inteligente?

segunda-feira, novembro 29, 2010

Current Biology 18, 429–434, March 25, 2008

Circular Polarization Vision in a Stomatopod Crustacean

Tsyr-Huei Chiou,1,4 Sonja Kleinlogel,2,4,5 Tom Cronin,1 Roy Caldwell,3 Birte Loeffler,2,6 Afsheen Siddiqi,1 Alan Goldizen,2 and Justin Marshall2,*

1Department of Biological Sciences
University of Maryland Baltimore County
1000 Hilltop Circle
Baltimore, Maryland 21250

2Sensory Neurobiology Group
Vision Touch and Hearing Research Centre
School of Biomedical Sciences and Queensland Brain Institute
The University of Queensland
Brisbane, Queensland 4072
Australia

3Department of Integrative Biology
University of California, Berkeley
3060 Valley Life Sciences Building #3140
Berkeley, California 94720-3140


Summary

We describe the addition of a fourth visual modality in the animal kingdom, the perception of circular polarized light. Animals are sensitive to various characteristics of light, such as intensity, color, and linear polarization [1, 2]. This latter capability can be used for object identification, contrast enhancement, navigation, and communication through polarizing reflections [2–4]. Circularly polarized reflections from a few animal species have also been known for some time [5, 6]. Although optically interesting [7, 8], their signal function or use (if any) was obscure because no visual system was known to detect circularly polarized light. Here, in stomatopod crustaceans, we describe for the first time a visual system capable of detecting and analyzing circularly polarized light. Four lines of evidence—behavior, electrophysiology, optical anatomy, and details of signal design—are presented to describe this new visual function. We suggest that this remarkable ability mediates sexual signaling and mate choice, although other potential functions of circular polarization vision, such as enhanced contrast in turbid environments, are also possible [7, 8]. The ability to differentiate the handedness of circularly polarized light, a visual feat never expected in the animal kingdom, is demonstrated behaviorally here for the first time.

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NOTA DESTE BLOGGER:

A seleção natural, o mecanismo evolucionário importante de Charles Darwin, mas não o único (tem de A a Z), é cego, aleatório e não teleológico nas suas proezas criativas quando lida com quaisquer formas vivas. Ué, e aqui no caso do sistema visual deste crustáceo estomatópode: object identification, contrast enhancement, navigation, and communication through polarizing reflections são todas funções télicas e, eu não pude resistir, sinais de inteligência detectados na natureza pelos pesquisadores através de QUATRO LINHAS DE EVIDÊNCIAS: behavior, electrophysiology, optical anatomy, and details of signal design.


Darwin, limitações teóricas e tecnológicas, à parte, já sentia calafrios com a visão humana, imagine se soubesse desta visão de polarização circular em um simples camarão.

Fui, nem sei por que pensando: o design é real na natureza, mas tem cegos como Richard Dawkins que são mais cegos do que os demais...