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September 20, 2014
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Nature’s vision: the ‘eyes’ have it

Frogs and other vertebrates have single lens eyes with a lens or cornea, an iris that controls the amount of light entering the eye, and a retina composed of many rods and cones, or the vision cells. This green frog cannot turn her head, but the eye placement enables her to see close to a full 180 degrees.


October 20, 2011

If we see a bird or some other creature, and it is close enough, there is something that usually catches our eye early in our observation: the eyes. In nature, there are many adaptations of vision. Earthworms have simple eyes (ocelli) that are able to detect light and dark, while eagles and hawks have single lens eyes with visual acuity five times greater than a human. (An eagle has five times the density of vision cells at the central focus area of the retina than humans do.)

Each animal species in its habitat requires different vision adaptations in order to survive and reproduce. Look at the images to get an “eyeful” of these varied vision adaptations.