I’ve always wondered how eyes evolved.
You need an optic nerve to transmit the info to the brain, but why would we evolve eyes without that, or an optic nerve without eyes. What purpose would it serve?
Maybe a random mutation led to eyes that were useless till then a nerve evolved like a million years later?
Or they both happened at the same time over a million years or so?
In: Biology
They evolved alongside each other, but essentially all you need is a nerve if the light detection is simple. Imagine a simple organism that has a single cell cluster that detects light. The output of this cluster is basically a binary “yes” or “no” to the question “is there light touching this cluster?” That would be the proto eye. That is whaf develops into a more complex eye. Insect eyes are kind of like this where instead of a single eye with an optical nerve it’s a bunch of simple photo receptors with a bunch of nerves that send signals to the brain.
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