Natural selection is the gradual, non-random process by which biological traits become either more or less common in a population. Individuals with certain variants of the trait survive and reproduce more than individuals with other variants.
There are hundreds of species of animal which, living in total darkness in deep caves, have no need for eyes. They range from fish (eg the Mexican blind cave tetra Astyanax fasciatus mexicanus) to insects (eg the Hawaiian cave planthopper Oliarus polyphemus), spiders (eg the Tooth Cave Spider Neoleptoneta myopica), salamanders (eg Typhlomolge rathbuni) and crayfish (eg the Dougherty Plain cave crayfish Cambarus cryptodytes).
Yet, these creatures do in fact have eyes. The eyes are often tiny, lacking crucial parts, so they would not function even if there were light to see. But they are clearly eyes, set in skull apertures, on stalks etc as normal, nevertheless. Eyes that don't work in creatures that don't even need eyes?
© Oolon Colluphid 2003, 2009
Why would evolution produce such a thing
Why would those who have such a poor design not die off and
Why wouldn't those with a better design be selected instead?
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