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
That’s not how evolution works. Evolution is a change in pattern, under reproductive pressure. The current anatomy distinctions, like eye and nerve, are retrospective analysis of the pattern, and don’t have anything to do with the pattern’s emergence.
Vision likely started with a light sensitive cell connected through a nerve into the brain. This is a “day vs night” detector pattern, which might sometimes provide reproductive advantage.
To use an incorrect camera analogy, because it’s ELI5 friendly, this likely changed from one-pixel daytime detection to many-pixel moving object detection to mega-pixel vision.
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