This member of the hydra family is a distant descendant of the very first animal to gain the ability to detect light.
This member of the hydra family is a distant descendant of the very first animal to gain the ability to detect light. David Plachetzki / University of California - San Diego/
This member of the hydra family is a distant descendant of the very first animal to gain the ability to detect light. David Plachetzki / University of California - San Diego/

National

November 06, 2007 7:00 AM

Scientists track early evolution of sight

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