Ep 80: When eyes are a problem



When eyes are a problem

Sometimes, evolution can take it back. Many cave dwelling animals have lost their eyes. Theories as to why this happen range from genetic drift, to mutations that improve other senses interfering with the proper development of eyes, to the energy cost of growing and maintaining vision. I suspect that it has to do with how easily injured eyes are when they don’t work. I’ve never seen that brought up by scientists; maybe you have to go blind to get it.

Here’s an article on the kiwi bird and how it may be losing its sight as a species. Special thanks to @seeingwithsound for the article and pointing me to this topic.

New Zealand’s iconic kiwi birds may be losing their sight

Here’s an article on changes in the brains of sightless animals.

Thanks to evolution, blind cave-dwellers are rapidly losing the visual parts of their brains

Here’s a paper on animals that have given up eyes, and how and why they may have done so.

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

Here’s an article on blind cave fish that includes a video.

How This Cave-Dwelling Fish Lost Its Eyes to Evolution

And an article on how the offspring of blind cave fish can regain their sight.

Blind Cavefish Can Produce Sighted Offspring


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