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Simple Eyes of Only Two Cells Guide Marine Zooplankton to the Light
piggy submitted, created time 1 month 2 weeks (www.sciencedaily.com)
Researchers unravel how the very first eyes in evolution might have worked and how they guide the swimming of marine plankton towards light.
Larvae of marine invertebrates – worms, sponges, jellyfish - have the simplest eyes that exist. They consist of no more than two cells: a photoreceptor cell and a pigment cell. These minimal eyes, called eyespots, resemble the "proto-eyes" suggested by Charles Darwin as the first eyes to appear in animal evolution. They cannot form images but allow the animal to sense the direction of light 
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