A questions regarding evolution from watching the excellent new BBC documentary Planet Earth. There are caves where organisms in complete darkness have evolved new ways of sensing their environment. It seems that as well as evolving new ways of sensing their environment, they have also lost their sense of sight, literally it would seem, losing their eyes.
How does this occur, eyes are redundant in the caves, but I’m not sure how they evolve out of a creature (for want of a better way of putting it). Does their creation involve the use of so much food/energy that those without do better and survive longer?
Didn’t see the show so don’t know what you mean by “new ways of sensing their environment,” but in terms of developing eyelessness, one way to think of it is that complex & relatively delicate things like eyes need selection to keep in the species. So many thing can go wrong. If through random mutations the eyes are messed up, but don’t harm the fish, then fish with messed up eyes will survive. If a mutation occurs that prevents full development of the eye and it doesn’t harm the fish, then it will continue. IANAGod, but not having something that can be damaged or infected may be an advantage and may have place selective pressure for it’s ‘removal.’
YMMV
Yeah, I should put “rely on their other senses in a way they didn’t before.” For example, an amphibian that is now eyeless uses a finely honed sense of touch that it wouldn’t otherwise have in its previous environment.
